Lifetime Direct Medical Costs of Treating Type 2 Diabetes and Diabetic Complications

      Background

      Lifetime direct medical cost of treating type 2 diabetes and diabetic complications in the U.S. is unknown.

      Purpose

      This study provides nationally representative estimates of lifetime direct medical costs of treating type 2 diabetes and diabetic complications in people newly diagnosed with type 2 diabetes, by gender and by age at diagnosis.

      Methods

      A type 2 diabetes simulation model was used to simulate the disease progression and direct medical costs among a cohort of newly diagnosed type 2 diabetes patients. The study sample used for the simulation was based on data from the 2009–2010 National Health and Nutritional Examination Survey. The costs of treating type 2 diabetes and diabetic complications were derived from published literature. Annual medical costs were accumulated over the life span of type 2 diabetes to determine the lifetime medical costs. All costs were calculated from a healthcare system perspective, and expressed in 2012 dollars.

      Results

      In men diagnosed with type 2 diabetes at ages 25–44 years, 45–54 years, 55–64 years, and ≥65 years, the lifetime direct medical costs of treating type 2 diabetes and diabetic complications were $124,700, $106,200, $84,000, and $54,700, respectively. In women, the costs were $130,800, $110,400, $85,500, and $56,600, respectively. The age–gender weighted average of the lifetime medical costs was $85,200, of which 53% was due to treating diabetic complications. The cost of managing macrovascular complications accounted for 57% of the total complication cost.

      Conclusions

      Over the lifetime, type 2 diabetes imposes a substantial economic burden on healthcare systems. Effective interventions that prevent or delay type 2 diabetes and diabetic complications might result in substantial long-term savings in healthcare costs.

      Introduction

      Nearly 26 million Americans currently live with diabetes. The disease imposes large and growing economic burdens on the healthcare system and society. The estimated total economic cost of diabetes in 2012 was $245 billion, including $176 billion in direct medical costs and $69 billion in reduced productivity.
      American Diabetes Association
      Economic costs of diabetes in the U.S. in 2012.
      The number of people in the U.S. with diabetes is projected to nearly double by 2034, with medical costs nearly tripling, to $336 billion.
      • Huang E.S.
      • Basu A.
      • O'Grady M.J.
      • Capretta J.C.
      Using clinical information to project federal health care spending.
      The economic burden of diabetes can be measured on the basis of prevalent cases or incident cases. The prevalence-based approach, which is used in most existing cost-of-diabetes studies, assesses the costs associated with diabetes in a given year, regardless of the length of time since diabetes became evident.
      American Diabetes Association
      Economic costs of diabetes in the U.S. in 2007.
      • Chen Y.
      • Quick W.W.
      • Yang W.
      • et al.
      Cost of gestational diabetes mellitus in the U.S. in 2007.
      • Ettaro L.
      • Songer T.J.
      • Zhang P.
      • Engelgau M.M.
      Cost-of-illness studies in diabetes mellitus.
      • Songer T.J.
      Studies on the cost of diabetes.
      A recent prevalence-based study, conducted by the American Diabetes Association, estimated that people with diabetes incur an average medical cost of ~$13,700 per year, of which ~$7900 is attributed to diabetes.
      American Diabetes Association
      Economic costs of diabetes in the U.S. in 2012.
      Although the prevalence-based cost studies provide useful measurement on the economic burden of the disease for a given period of time, they do not reveal the long-term economic consequences associated with a new incident case of type 2 diabetes.
      In contrast, the incidence-based costing method measures the cumulative costs of an incident case of diabetes from onset or diagnosis to death. Compared with the prevalence-based costs, such a method is more useful for understanding the long-term fiscal impact of type 2 diabetes on individual and healthcare systems. Incidence-based costs are also critical for public health officials and private insurers in evaluating the potential long-term financial return and cost effectiveness of type 2 diabetes prevention programs. Despite the relevance, few studies have assessed the lifetime medical cost of type 2 diabetes. To our knowledge, no national-level estimates of the lifetime cost of diabetes are yet available in the U.S.
      Estimating incidence-based costs is challenging, because it usually requires a longitudinal follow-up of patients. Such longitudinal data are relatively scarce and expensive to collect. Without empirical data, incidence-based estimates can be calculated using a disease simulation model that simulates the natural progression of diseases and the associated costs. In the present study, a validated type 2 diabetes simulation model was used to estimate the lifetime direct medical costs of treating type 2 diabetes and diabetic complications in people with newly diagnosed type 2 diabetes in the U.S.

      Methods

      Type 2 Diabetes Simulation Model

      The current simulation model is a Markov-based lifetime model that follows a cohort of people from the time of type 2 diabetes diagnosis to death.
      CDC Diabetes Cost-effectiveness Group
      Cost-effectiveness of intensive glycemic control, intensified hypertension control, and serum cholesterol level reduction for type 2 diabetes.
      • Hoerger T.J.
      • Segel J.E.
      • Zhang P.
      • Sorensen S.W.
      Validation of the CDC-RTI diabetes cost-effectiveness model.
      The model includes the annual transition probabilities between disease stages and death. The basic model structure has been described previously,
      CDC Diabetes Cost-effectiveness Group
      Cost-effectiveness of intensive glycemic control, intensified hypertension control, and serum cholesterol level reduction for type 2 diabetes.
      • Herman W.H.
      • Hoerger T.J.
      • Brandle M.
      • et al.
      The cost-effectiveness of lifestyle modification or metformin in preventing type 2 diabetes in adults with impaired glucose tolerance.
      • Hoerger T.J.
      • Harris R.
      • Hicks K.A.
      • Donahue K.
      • Sorensen S.
      • Engelgau M.
      Screening for type 2 diabetes mellitus: a cost-effectiveness analysis.
      and the technical details of the model have also been presented.
      • Herman W.H.
      • Hoerger T.J.
      • Brandle M.
      • et al.
      The cost-effectiveness of lifestyle modification or metformin in preventing type 2 diabetes in adults with impaired glucose tolerance.
      The model has been validated against major clinical trials and been found to accurately predict the progression of the disease and development of complications.
      • Hoerger T.J.
      • Segel J.E.
      • Zhang P.
      • Sorensen S.W.
      Validation of the CDC-RTI diabetes cost-effectiveness model.
      This model has previously been used to evaluate the cost effectiveness of interventions designed to prevent or delay type 2 diabetes or prevent diabetic complications.
      CDC Diabetes Cost-effectiveness Group
      Cost-effectiveness of intensive glycemic control, intensified hypertension control, and serum cholesterol level reduction for type 2 diabetes.
      • Herman W.H.
      • Hoerger T.J.
      • Brandle M.
      • et al.
      The cost-effectiveness of lifestyle modification or metformin in preventing type 2 diabetes in adults with impaired glucose tolerance.
      • Zhuo X.
      • Zhang P.
      • Gregg E.W.
      • et al.
      A nationwide community-based lifestyle program could delay or prevent type 2 diabetes cases and save $5.7 billion in 25 years.
      For this analysis, the model was used to simulate the disease progression among eight cohorts of newly diagnosed type 2 diabetes patients. They are women and men diagnosed with type 2 diabetes at ages 25–44 years, 45–54 years, 55–64 years, and ≥65 years in 2009–2010. Demographic characteristics and prevalence of hypertension, cholesterol level, and smoking status of the simulated cohorts are based on data of year 2009–2010 from the National Health and Nutritional Examination Survey.
      National Center for Health Statistics
      National Health and Nutrition Examination Survey Data.
      The most common diabetic complications are simulated by five separate modules, including nephropathy; neuropathy; and retinopathy (microvascular) and stroke and coronary heart diseases (macrovascular; Figure 1).
      • Fowler M.
      Microvascular and macrovascular complications of diabetes.
      Approximately 58% of patients with diabetes have at least one microvascular or macrovascular complication.
      • Mitka M.
      Report quantifies diabetes complications.
      These five diabetic complications were included in the model primarily because, first, the injurious effects of hyperglycemia on microvascular and macrovascular systems are well established by a large body of clinical evidence
      • Fowler M.
      Microvascular and macrovascular complications of diabetes.
      ; second, those complications are measured as the primary endpoint outcomes in the United Kingdom Prospective Diabetes Study (UKPDS) and most of the other major clinical trials.
      UK Prospective Diabetes Study Group
      Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38.
      Action to Control Cardiovascular Risk in Diabetes Study Group, Gerstein HC, Miller ME, Byington RP, et al
      Effects of intensive glucose lowering in type 2 diabetes.
      • Gazi I.F.
      • Mikhailidis D.P.
      Efficacy and safety of atorvastatin in the prevention of cardiovascular end points in subjects with type 2 diabetes: the Atorvastatin Study for Prevention of Coronary Heart Disease Endpoints in Non-Insulin-Dependent Diabetes Mellitus (ASPEN): response to Knopp.
      ADVANCE Collaborative Group
      Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes.
      • Hemmingsen B.
      • Lund S.S.
      • Gluud C.
      • et al.
      Intensive glycaemic control for patients with type 2 diabetes: systematic review with meta-analysis and trial sequential analysis of randomised clinical trials.
      Figure thumbnail gr1
      Figure 1Simulations of the development of diabetic complication.
      Note: The five diabetic complications are the most common complications among type 2 diabetic patients. It was estimated that 35% of diabetic patients had heart disease or stroke (www.cdc.gov/diabetes/statistics/cvd/fig3.htm); 29% of people with diabetes aged ≥40 years had diabetic retinopathy (diabetes.niddk.nih.gov/dm/pubs/statistics/#Blindness); about 60%–70% of people with diabetes had mild to severe forms of neuropathy. About 40% of diabetic patients have chronic renal disease (www.ncbi.nlm.nih.gov/pubmed/20338960).CA, cardiac arrest; CHD, coronary heart disease; ESRD, end-stage renal disease; LEA, lower-extremity amputation; MI, myocardial infarction
      The clinical progression of the five disease pathways was primarily based on data from the UKPDS,
      UK Prospective Diabetes Study Group
      Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38.
      • Adler A.I.
      • Stevens R.J.
      • Manley S.E.
      • Bilous R.W.
      • Cull C.A.
      • Holman R.R.
      Development and progression of nephropathy in type 2 diabetes: the United Kingdom Prospective Diabetes Study (UKPDS 64).
      • Haak T.
      Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group.
      UK Prospective Diabetes Study (UKPDS) Group
      Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34).
      • Stevens R.J.
      • Kothari V.
      • Adler A.I.
      • Stratton I.M.
      The UKPDS risk engine: a model for the risk of coronary heart disease in Type II diabetes (UKPDS 56).
      which is the largest and longest clinical study concerning the effect of intensive glycemic control on diabetes-related microvascular and macrovascular complications among newly diagnosed type 2 diabetic patients. Patients in the intensive intervention arm of the UKPDS received an intensive glycemic control with a treatment goal of a hemoglobin A1c level of 7.0%. Patients who had hypertension or hyperlipidemia also received intensive blood pressure control and intensive cholesterol control, respectively.
      UK Prospective Diabetes Study (UKPDS) Group
      Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33).
      Such treatment regimens have been part of the treatment standard recommended by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD).
      • Nathan D.M.
      • Buse J.B.
      • Davidson M.B.
      • et al.
      Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes.
      In the model, the deaths of the people with diabetes could be attributed to end-stage renal disease; lower extremity amputation (LEA); coronary heart disease; stroke; and other causes. In addition to the increased mortalities due to type 2 diabetes–related complications, higher mortalities were assumed for people with type 2 diabetes than for those without.
      • Gregg E.W.
      • Gu Q.
      • Cheng Y.J.
      • Narayan K.M.
      • Cowie C.C.
      Mortality trends in men and women with diabetes, 1971 to 2000.

      Direct Medical Costs

      Direct medical costs were defined as the medical cost of managing type 2 diabetes and medical costs of treating diabetic complications. Lifetime direct medical costs were calculated in two steps. First, annual direct medical costs of diabetes management and treating diabetes-related complications were estimated based on published literature. Second, these annual estimates were assigned to the life-years in which an individual had diabetes, and life-years in which patients had complications, respectively.
      Annual medical costs were accumulated from the diagnosis of type 2 diabetes in 2010 to death to determine the per capita lifetime direct medical costs for each of the eight age- and gender-specific cohorts. After calculating the per capita costs of the people in the eight cohorts, the national weighted average lifetime cost per person was calculated by the sum of the products of the per capita costs of each cohort by the proportions of the populations they represented. The weighted average represents the lifetime direct medical cost for an average person who was diagnosed with type 2 diabetes in 2010. All costs were rounded to the nearest $100 and expressed in 2012 U.S. dollars. Future costs were discounted at a 3% annual discount rate.

      Medical Costs of Diabetes Management

      The cost of managing type 2 diabetes included the cost of medications, physician visits, and self-testing devices (Table 1). Based on a treatment algorithm recommended by the ADA and the EASD,
      • Nathan D.M.
      • Buse J.B.
      • Davidson M.B.
      • et al.
      Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes.
      newly diagnosed diabetic patients received, at diagnosis, both metformin and a lifestyle intervention. Other drugs (e.g., sulfonylureas, glitazones, and insulin) would be added if needed to achieve/maintain a hemoglobin A1c level of <7.0%. Metformin was used in 54% of treatments, sulfonylureas in 34%, glitazones in 28%, and insulin in 28%.
      • Alexander G.C.
      • Sehgal N.L.
      • Moloney R.M.
      • Stafford R.S.
      National trends in treatment of type 2 diabetes mellitus, 1994-2007.
      Total medication costs were calculated by multiplying the total quantity of each drug used by the price for that drug. Price data were obtained from Red Book 2010: Pharmacy’s Fundamental Reference (hereafter simply Red Book 2010).

      Red book: pharmacy’s fundamental reference, 2010 edition. New York: Thomson Reuters, 2010

      Table 1Direct medical costs of type 2 diabetic care and diabetic complications
      Cost of one-time incidence ($)Annual medical cost ($)Study/source
      TYPE 2 DIABETES CARE
      Medications148–597
      The estimated annual cost increases from $148 in the year of diagnosis to $597 in the year of death or up to age 94 years. A detailed calculation has been presented previously.9
      Nathan (2009)
      • Nathan D.M.
      • Buse J.B.
      • Davidson M.B.
      • et al.
      Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes.
      Alexander (2008)
      • Alexander G.C.
      • Sehgal N.L.
      • Moloney R.M.
      • Stafford R.S.
      National trends in treatment of type 2 diabetes mellitus, 1994-2007.
      Red Book 2010

      Red book: pharmacy’s fundamental reference, 2010 edition. New York: Thomson Reuters, 2010

      Physician visits
       Non–insulin users477National Health Interview Survey data
      National Center for Health Statistics
      National Health Interview Survey diabetes supplement.
       Insulin users522Medicare Fee Schedule 2012
      Self-testing device
       Non–insulin users90National Health Interview Survey data
      National Center for Health Statistics
      National Health Interview Survey diabetes supplement.
       Insulin users278Red Book 2010

      Red book: pharmacy’s fundamental reference, 2010 edition. New York: Thomson Reuters, 2010

      DIABETIC COMPLICATIONS
      Nephropathy
       Microalbuminuria430Nichols (2011)
      • Nichols G.A.
      • Vupputuri S.
      • Lau H.
      Medical care costs associated with progression of diabetic nephropathy.
       Macroalbuminuria/Clinical  nephropathy3,936Nichols (2011)
      • Nichols G.A.
      • Vupputuri S.
      • Lau H.
      Medical care costs associated with progression of diabetic nephropathy.
       End-stage renal disease78,795USRDS 2012
      NIH, National Institute of Diabetes and Digestive and Kidney Diseases
      USRDS 2012 annual data report: atlas of chronic kidney disease and end-stage renal disease in the U.S.
      Neuropathy
       Peripheral neuropathy523
       Diabetic foot ulcer17,959
       Initial lower-extremity  amputationFatalNonfatal78,48057,032O’Brien (2003)
      • O'Brien J.A.
      • Patrick A.R.
      • Caro J.J.
      Cost of managing complications resulting from type 2 diabetes mellitus in Canada.
       Subsequent lower-extremity  amputationFatalNonfatal78,48057,032
      Retinopathy
       Photocoagulation
        Aged <65 years1850686
        Aged ≥65 years1850649Rein (2006)
      • Rein D.B.
      • Zhang P.
      • Wirth K.E.
      • et al.
      The economic burden of major adult visual disorders in the U.S.
       Glaucoma/blindness
        Aged <64 years3654
        Aged ≥65 years6101
      Coronary heart disease
       Angina8,4642187
       Death from cardiac arrest or  myocardial infarction without hospitalization1,186O'Brien (2003)
      • O'Brien J.A.
      • Patrick A.R.
      • Caro J.J.
      Cost of managing complications resulting from type 2 diabetes mellitus in Canada.
       Death from cardiac arrest or  myocardial infarction within 30 days of hospitalization24,414
       Nonfatal cardiac arrest or  myocardial infarction42,662
       History of cardiac arrest or  myocardial infarction2,358
      Stroke, by age in years
       ≤4481,85015,682
       45–5481,8508,952
       55–6481,85028,943O’Brien (2003)
      • O'Brien J.A.
      • Patrick A.R.
      • Caro J.J.
      Cost of managing complications resulting from type 2 diabetes mellitus in Canada.
       65–7463,37423,139Taylor (1996)
      • Taylor T.N.
      • Davis P.H.
      • Torner J.C.
      • Holmes J.
      • Meyer J.W.
      • Jacobson M.F.
      Lifetime cost of stroke in the U.S.
       75–8460,19920,084
       ≥8546,8408,788
      Cost of death, by age in years
       ≤7419,870
       75–8417,307Hogan (2001)
      • Hogan C.
      • Lunney J.
      • Gabel J.
      • Lynn J.
      Medicare beneficiaries’ costs of care in the last year of life.
       ≥8511,747
      Note: All costs are in 2012 dollars.
      USRDS, U.S. Renal Data System
      a The estimated annual cost increases from $148 in the year of diagnosis to $597 in the year of death or up to age 94 years. A detailed calculation has been presented previously.
      • Herman W.H.
      • Hoerger T.J.
      • Brandle M.
      • et al.
      The cost-effectiveness of lifestyle modification or metformin in preventing type 2 diabetes in adults with impaired glucose tolerance.
      The frequencies of physician office visits were derived from data of the National Health Interview Survey Diabetes Supplement.
      National Center for Health Statistics
      National Health Interview Survey diabetes supplement.
      The data suggest that people with type 2 diabetes who were not using insulin made an average of seven physician office visits per year; those using insulin made an average of eight office visits per year. During a regular office visit, patients were assumed to receive a hemoglobin A1c test and 25 minutes of counseling. In addition to regular visits, patients received a more comprehensive visit per year, in which patients would receive 35 minutes of counseling, a hemoglobin A1c test, a urinalysis, an albumin and creatinine test, and a lipid test.
      Based on the 2012 Medicare fee schedule, the cost of a regular visit was estimated at $50 and the cost of an annual visit at $110. The number of visits was multiplied by their respective unit cost by visit type to determine the annual total cost for physician office visits. To calculate the annual cost of self-testing, the level of use of self-testing was first estimated based on data from the National Health Interview Survey Diabetes Supplement.
      National Center for Health Statistics
      National Health Interview Survey diabetes supplement.
      On average, insulin users conducted self-testing three times daily; those not using insulin conducted self-testing once daily. The self-testing devices included glucose test strips, lancets, glucose meters, and glucagon. The total number of each device used per year was multiplied by the unit cost of that device (based on Red Book 2010) to determine the annual cost of self-testing.

      Medical Costs of Diabetic Complications

      Annual costs of diabetic complications were defined as the cost of a one-time event in the year it first occurred and the annual treatment cost in subsequent years. A comprehensive literature review was conducted to obtain the up-to-date estimates on the medical costs of the disease states simulated in the diabetic complication model (Table 1).
      Medical costs of nephropathy include the costs of microalbuminuria, macroalbuminuria/clinical nephropathy, and end-stage renal disease. The costs came from a study of Kaiser Permanente patients
      National Center for Health Statistics
      National Health Interview Survey diabetes supplement.
      and the U.S. Renal Data System.
      • Hogan C.
      • Lunney J.
      • Gabel J.
      • Lynn J.
      Medicare beneficiaries’ costs of care in the last year of life.
      The costs of diabetic neuropathy, including peripheral neuropathy, diabetic foot ulcer and LEA, are based on a study by O’Brien et al.
      • O'Brien J.A.
      • Patrick A.R.
      • Caro J.J.
      Cost of managing complications resulting from type 2 diabetes mellitus in Canada.
      Fatal and nonfatal LEA were reported separately. Medical costs of diabetic retinopathy were separated into the cost of photocoagulation and blindness, taken from Rein and colleagues’ study
      • Rein D.B.
      • Zhang P.
      • Wirth K.E.
      • et al.
      The economic burden of major adult visual disorders in the U.S.
      based on private insurance and Medicare claims data. The medical costs of coronary heart diseases and stroke were primarily based on a study by O’Brien et al.
      • O'Brien J.A.
      • Patrick A.R.
      • Caro J.J.
      Cost of managing complications resulting from type 2 diabetes mellitus in Canada.
      and a study by Taylor et al.
      • Taylor T.N.
      • Davis P.H.
      • Torner J.C.
      • Holmes J.
      • Meyer J.W.
      • Jacobson M.F.
      Lifetime cost of stroke in the U.S.
      The medical costs of death caused by complications other than neuropathy and coronary heart disease were based on a study of Medicare data.
      • Hogan C.
      • Lunney J.
      • Gabel J.
      • Lynn J.
      Medicare beneficiaries’ costs of care in the last year of life.

      Sensitivity Analyses

      The uncertainties of the lifetime cost estimates were examined by varying each of the cost parameters used in the model. The baseline value of the cost parameters was varied from the lower value to the upper value of the 95% CIs. If CIs were not available, the parameter was varied from 50% and 150% of the baseline values. In addition, an alternative method for calculating costs from diabetic complications was used. In the base-case analysis, the cost of diabetic complications was computed using an additive costing method. Therefore, medical costs other than the modeled diabetic complications (e.g., hypoglycemia and stomach nerve damage) were not included in the cost calculation. In the alternative costing method, complication costs were estimated using a regression-based multiplicative model based on data from an employer-based insurance plan.
      • Brandle M.
      • Zhou H.
      • Smith B.R.
      • et al.
      The direct medical cost of type 2 diabetes.
      The annual medical cost of complications was calculated as the product of the estimated baseline cost and the multipliers corresponding to cohort characteristics and all the possible diabetic complications.

      Results

      Table 2 presents the lifetime direct medical costs (in 2012 dollars) in women and men who were diagnosed with type 2 diabetes in 2010. The lifetime medical cost of treating diabetes and diabetic complications in men who were diagnosed at ages 25–44 years was $124,700. The lifetime direct medical cost was lower in patients who were diagnosed when older: $106,200 for men diagnosed with type 2 diabetes at ages 45–54 years, $84,000 when diagnosed at 55–64 years, and $54,700 when diagnosed at aged ≥65 years. Women with type 2 diabetes had slightly higher lifetime medical cost. The costs were $130,800 when diagnosed at ages 25–44 years, $110,400 when diagnosed at ages 45–54 years, $85,500 when diagnosed at ages 55–64 years, and $56,600 when diagnosed at ages ≥65 years. The overall gender- and age-weighted average lifetime medical cost of treating diabetes and its related complications was $85,200.
      Table 2Lifetime direct medical costs in patients with type 2 diabetes
      Age at diagnosis, years
      25–4445–5455–64≥65
      MEN
      Total, $ (%)124,700106,20084,00054,700
       Diabetes management61,800 (50)49,100 (46)35,600 (42)19,700 (36)
       Nephropathy10,600 (9)7,100 (7)4,000 (5)1,600 (3)
       Neuropathy13,400 (11)6,600 (6)4,200 (5)2,000 (4)
       Retinopathy5,900 (5)8,400 (8)5,400 (6)2,700 (5)
       Coronary heart disease19,200 (15)15,400 (15)14,800 (18)13,000 (24)
       Stroke13,800 (11)19,600 (18)20,000 (24)15,700 (29)
      WOMEN
      Total, $ (%)130,800110,40085,50056,600
       Diabetes management67,600 (52)52,800 (48)39,700 (46)25,300 (45)
       Nephropathy16,200 (12)9,100 (8)5,200 (6)2,400 (4)
       Neuropathy12,200 (9)8,100 (7)5,400 (6)2,800 (5)
       Retinopathy9,400 (7)10,300 (9)6,900 (8)3,800 (7)
       Coronary heart disease6,600 (5)10,100 (9)9,700 (11)7,600 (13)
       Stroke18,800 (14)20,000 (18)18,600 (22)14,700 (26)
      Note: All costs are in 2012 U.S. dollars (discounted at 3% per year for any costs beyond 2012). Percentage values in parentheses indicate percentage of total.
      Diabetic complications account for 48%–64% of the lifetime medical cost. Of the medical costs of diabetic complications, 57% were spent on treating stroke and coronary heart disease. Patients diagnosed at older ages spent a greater proportion of their expenses on diabetic complications than younger patients. For example, men diagnosed with type 2 diabetes when aged ≥65 years spent about 64% on treating diabetic complications, compared with 50% in men diagnosed when aged 25–44 years.

      Sensitivity Analyses

      Figure 2 shows the results of the sensitivity analyses in men who were diagnosed at ages 45–54 years. Results from other cohorts were similar. The annual treatment cost of stroke and the cost of incident cases of nonfatal cardiac arrest or myocardial infarction were most influential on the lifetime cost estimates. The lifetime medical cost would be reduced by up to $10,000 or increased by up to $8100 if either of the two parameters changed. Varying any of the other individual cost components resulted in a change of no more than $3000 from the base-case estimates. Adopting an alternative multiplicative costing method for the costs of diabetic complications increased the total lifetime cost by up to $3200.
      Figure thumbnail gr2
      Figure 2Univariate sensitivity analyses in diabetic men diagnosed at age 45–54 years.
      Note: The horizontal axis is the difference of the lifetime cost from the estimate in base-case analysis. For example, varying the cost of new incident stroke to the upper limit of its estimate increased the lifetime cost estimate by more than $4000.CA, cardiac arrest; ESRD, end-stage renal disease; LEA, lower-extremity amputation; MI, myocardial infarction

      Discussion

      Type 2 diabetes imposes a persistent economic burden over the life span. However, no estimates of lifetime medical costs of type 2 diabetes are available in the U.S. The present study provides estimates of the lifetime costs of treating type 2 diabetes and diabetic complications, stratified by gender and the age of diagnosis. The current estimates indicate that the financial burden of a new case of type 2 diabetes imposed on the healthcare system is substantial, and this financial burden is particularly high in people diagnosed with type 2 diabetes at younger ages, primarily because of the longer cumulative exposure to diabetes. Women were found to have greater lifetime medical costs than men. This is primarily because even though women have fewer complications, on average, they live longer than men.
      • Adler A.I.
      • Stevens R.J.
      • Manley S.E.
      • Bilous R.W.
      • Cull C.A.
      • Holman R.R.
      Development and progression of nephropathy in type 2 diabetes: the United Kingdom Prospective Diabetes Study (UKPDS 64).
      • Nathan D.M.
      • Buse J.B.
      • Davidson M.B.
      • et al.
      Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes.
      The current estimated lifetime medical costs of diabetic complications were in line with the estimates previously reported by Caro and colleagues (an estimated lifetime medical cost of diabetic complications to be $47,000 over 30 years).
      • Caro J.J.
      • Ward A.J.
      • O'Brien J.A.
      Lifetime costs of complications resulting from type 2 diabetes in the U.S.
      Among the few lifetime cost studies, Birnbaum and colleagues estimated the lifetime incremental medical cost among diabetic women using data from an employer-based insurance claims.
      • Birnbaum H.
      • Leong S.
      • Kabra A.
      Lifetime medical costs for women: cardiovascular disease, diabetes, and stress urinary incontinence.
      However, the Birnbaum estimates are different than those reported in the present study, because the Birnbaum study estimated the incremental cost by comparing the costs of people with and without diabetes.
      In addition, the authors also included both direct and indirect medical costs among women with diabetes (type 1 and type 2). In contrast, the present study examined direct medical costs among type 2 diabetes patients only. No comparison was made of the cost with that of the people without diabetes. A study by Goldman and colleagues assessed the lifetime medical spending among the elderly under hypothetic scenarios of diabetes prevention.
      • Goldman D.P.
      • Zheng Y.
      • Girosi F.
      • et al.
      The benefits of risk factor prevention in Americans aged 51 years and older.
      However, their estimate represents the medical cost of average people (i.e., people with or without diabetes) and is therefore not comparable.
      The substantial lifetime medical cost highlights the potential economic return of diabetes prevention. Policymakers have called for additional efforts to prevent type 2 diabetes, particularly among people who are at high risk for developing type 2 diabetes.

      CDC. National Diabetes Prevention Program. 2011 11/04/2011 [cited 2012 06/01/2012]. www.cdc.gov/diabetes/prevention/index.htm.

      Major clinical trials from the U.S. and other countries have established that, among those with elevated glucose levels, structured lifestyle modifications can reduce the risk of developing diabetes by 40%–60%.
      • Knowler W.C.
      • Barrett-Connor E.
      • Fowler S.E.
      • et al.
      Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.
      • Pan X.R.
      • Li G.W.
      • Hu Y.H.
      • et al.
      Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. The Da Qing IGT and Diabetes Study.
      • Tuomilehto J.
      • Lindstrom J.
      • Eriksson J.G.
      • et al.
      Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance.
      A recent study further suggests that the reduction in the risk of diabetes can be achieved at a relatively low cost.
      • Ali M.K.
      • Echouffo-Tcheugui J.
      • Williamson D.F.
      How effective were lifestyle interventions in real-world settings that were modeled on the Diabetes Prevention Program?.
      However, the cost effectiveness of such prevention efforts depends on the magnitude of the downstream costs that ultimately would be saved. The current lifetime cost estimates clearly show that, if type 2 diabetes and diabetic complications could be prevented, a substantial downstream cost could be potentially saved. This finding reinforces earlier evidence that clinical and community-based interventions to prevent type 2 diabetes could be highly cost effective.
      • Li R.
      • Zhang P.
      • Barker L.E.
      • Chowdhury F.M.
      • Zhang X.
      Cost-effectiveness of interventions to prevent and control diabetes mellitus: a systematic review.
      The present study also indicates the economic importance of glycemic management to prevent diabetic complications in type 2 diabetes patients. Diabetic complications accounted for more than half of the lifetime direct medical costs among patients with type 2 diabetes, and the majority of those costs were associated with macrovascular diseases. Poor adherence to recognized standards of management care in glycemic, blood pressure, and cholesterol control is a primary cause of increased risk for diabetic complications.
      • De Geest S.
      • Sabate E.
      Adherence to long-term therapies: evidence for action.
      Among people with diabetes, only 3% of insulin users and 1% of nonusers met all five of the ADA’s recommended standards for risk factor management and complication prevention.
      • Beckles G.L.
      • Engelgau M.M.
      • Narayan K.M.
      • Herman W.H.
      • Aubert R.E.
      • Williamson D.F.
      Population-based assessment of the level of care among adults with diabetes in the U.S.
      The present study suggests that decreasing the incidence of complications could have a major cost impact. Therefore, from a cost perspective, it is important that people with diabetes achieve appropriate treatment targets of diabetes management care to reduce the risk of complications.
      The current lifetime cost estimates provide a basis for public or private healthcare systems to assess the long-term fiscal impact of type 2 diabetes. Currently, there are about 26 million American adults who have diagnosed diabetes; 90%–95% of those have type 2 diabetes,

      CDC. National diabetes fact sheet. 2011. www.cdc.gov/diabetes/pubs/pdf/ndfs_2011.pdf.

      and given the lifetime cost of medical treatment, the total economic resources used for caring for this population in the next several decades would be enormous. For example, the current population aged ≥65 years would be expected to create about $170 billion in lifetime medical spending. Further, given that prevalence of type 2 diabetes increases in younger people,
      • Koopman R.J.
      • Mainous 3rd, A.G.
      • Diaz V.A.
      • Geesey M.E.
      Changes in age at diagnosis of type 2 diabetes mellitus in the United States, 1988 to 2000.
      lifetime medical costs in future cohorts of patients would likely increase.
      Because of the large degree of uncertainty with extant estimates of the indirect costs of type 2 diabetes, the lifetime indirect costs were not considered in the present study. A large body of literature has suggested that type 2 diabetes is associated with reduced workforce participation, workday absence, and reduced productivity at work. In fact, a recent prevalence-based study estimated that the annual productivity loss per person with diabetes (including type 1 and type 2) was nearly half that of direct medical costs.
      American Diabetes Association
      Economic costs of diabetes in the U.S. in 2012.
      If this estimate is similar for incidence-based costs, people with diabetes would also incur considerable indirect costs over their lifetime.

      Limitations

      The study has several limitations. First, as in other modeling studies, it was assumed that current treatment costs for type 2 diabetes and its complications would remain relatively stable. If any significant changes occur because of advances in medical technologies or other unforeseen factors, the current lifetime estimates would need revision. Second, the simulation model was developed based on data collected from multiple sources and thus was inevitably subject to the accuracy of the data sources and the assumptions employed by the researchers in source studies. In particular, because no U.S.-based data were available at the time of the analysis, the simulation of the progression of diabetes was primarily based on data from a UK-based clinical trial. However, because diabetic pathology is generally believed to be similar, UKPDS has been used as the clinical base for the ADA’s recommendation for the standard of diabetes care in the U.S.
      American Diabetes Association
      Implications of the United Kingdom Prospective Diabetes Study.
      American Diabetes Association
      Standards of medical care in diabetes—2010.
      Third, because of constraints on computation power, a full probabilistic sensitivity analysis could not be performed. Ideally, the model parameters would be sampled from the distributions simultaneously to determine the change of the lifetime cost estimate. Fourth, without a nondiabetic cohort as a comparison group, it was not possible to compare the costs for people with/without diabetes; thus, the incremental cost attributable to type 2 diabetes could not be calculated. Future models could examine the incremental cost if longitudinal data are available in both groups. Finally, the current model only simulated five of the most common diabetic complications. Because of lack of data, other complications such as hypoglycemia were not considered. Had those costs been included, the lifetime medical cost of diabetic complications would have been greater.

      Conclusion

      Type 2 diabetes imposes a substantial lifetime economic burden on healthcare systems. This high lifetime cost highlights the potential long-term fiscal return on investment of interventions to prevent or delay type 2 diabetes or diabetic complications. The current lifetime cost estimates can be used as one of the benefit measures to evaluate the economic efficiency of various type 2 diabetes prevention and control policies or programs.

      Acknowledgements

      The authors thank Lawrence Barker, PhD, and Barbara Bardenheier, PhD, of the CDC for helpful comments, and Tony Pearson-Clarke of the CDC for the excellent editing.
      The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the CDC.
      No financial disclosures were reported by the authors of this paper.

      References

        • American Diabetes Association
        Economic costs of diabetes in the U.S. in 2012.
        Diabetes Care. 2013; 36: 1033-1046
        • Huang E.S.
        • Basu A.
        • O'Grady M.J.
        • Capretta J.C.
        Using clinical information to project federal health care spending.
        Health Aff (Millwood). 2009; 28: w978-990
        • American Diabetes Association
        Economic costs of diabetes in the U.S. in 2007.
        Diabetes Care. 2008; 31: 596-615
        • Chen Y.
        • Quick W.W.
        • Yang W.
        • et al.
        Cost of gestational diabetes mellitus in the U.S. in 2007.
        Popul Health Manag. 2009; 12: 165-174
        • Ettaro L.
        • Songer T.J.
        • Zhang P.
        • Engelgau M.M.
        Cost-of-illness studies in diabetes mellitus.
        Pharmacoeconomics. 2004; 22: 149-164
        • Songer T.J.
        Studies on the cost of diabetes.
        Diabetes public health resource. 1998; (www.cdc.gov/diabetes/pubs/costs/intro.htm#references)
        • CDC Diabetes Cost-effectiveness Group
        Cost-effectiveness of intensive glycemic control, intensified hypertension control, and serum cholesterol level reduction for type 2 diabetes.
        JAMA. 2002; 287: 2542-2551
        • Hoerger T.J.
        • Segel J.E.
        • Zhang P.
        • Sorensen S.W.
        Validation of the CDC-RTI diabetes cost-effectiveness model.
        Research Triangle Park NC: RTI International. 2009;
        • Herman W.H.
        • Hoerger T.J.
        • Brandle M.
        • et al.
        The cost-effectiveness of lifestyle modification or metformin in preventing type 2 diabetes in adults with impaired glucose tolerance.
        Ann Intern Med. 2005; 142: 323-332
        • Hoerger T.J.
        • Harris R.
        • Hicks K.A.
        • Donahue K.
        • Sorensen S.
        • Engelgau M.
        Screening for type 2 diabetes mellitus: a cost-effectiveness analysis.
        Ann Intern Med. 2004; 140: 689-699
        • Zhuo X.
        • Zhang P.
        • Gregg E.W.
        • et al.
        A nationwide community-based lifestyle program could delay or prevent type 2 diabetes cases and save $5.7 billion in 25 years.
        Health Aff (Millwood). 2012; 31: 50-60
        • National Center for Health Statistics
        National Health and Nutrition Examination Survey Data.
        DHHS, CDC, Hyattsville MD2010
        • Fowler M.
        Microvascular and macrovascular complications of diabetes.
        Clin Diabetes. 2011; 29: 6
        • Mitka M.
        Report quantifies diabetes complications.
        JAMA. 2007; 297: 2337-2338
        • UK Prospective Diabetes Study Group
        Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38.
        BMJ. 1998; 317: 703-713
        • Action to Control Cardiovascular Risk in Diabetes Study Group, Gerstein HC, Miller ME, Byington RP, et al
        Effects of intensive glucose lowering in type 2 diabetes.
        N Engl J Med. 2008; 358: 2545-2559
        • Gazi I.F.
        • Mikhailidis D.P.
        Efficacy and safety of atorvastatin in the prevention of cardiovascular end points in subjects with type 2 diabetes: the Atorvastatin Study for Prevention of Coronary Heart Disease Endpoints in Non-Insulin-Dependent Diabetes Mellitus (ASPEN): response to Knopp.
        Diabetes Care. 2006; 29 (author reply 2561–2): 2561
        • ADVANCE Collaborative Group
        Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes.
        N Engl J Med. 2008; 358: 2560-2572
        • Hemmingsen B.
        • Lund S.S.
        • Gluud C.
        • et al.
        Intensive glycaemic control for patients with type 2 diabetes: systematic review with meta-analysis and trial sequential analysis of randomised clinical trials.
        BMJ. 2011; 343: d6898
        • Adler A.I.
        • Stevens R.J.
        • Manley S.E.
        • Bilous R.W.
        • Cull C.A.
        • Holman R.R.
        Development and progression of nephropathy in type 2 diabetes: the United Kingdom Prospective Diabetes Study (UKPDS 64).
        Kidney Int. 2003; 63: 225-232
        • Haak T.
        Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group.
        Lancet. 1998; 352: 837-853
        • UK Prospective Diabetes Study (UKPDS) Group
        Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34).
        Lancet. 1998; 352: 854-865
        • Stevens R.J.
        • Kothari V.
        • Adler A.I.
        • Stratton I.M.
        The UKPDS risk engine: a model for the risk of coronary heart disease in Type II diabetes (UKPDS 56).
        Clin Sci (Lond). 2001; 101: 671-679
        • UK Prospective Diabetes Study (UKPDS) Group
        Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33).
        Lancet. 1998; 352: 837-853
        • Nathan D.M.
        • Buse J.B.
        • Davidson M.B.
        • et al.
        Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes.
        Diabetes Care. 2009; 32: 193-203
        • Gregg E.W.
        • Gu Q.
        • Cheng Y.J.
        • Narayan K.M.
        • Cowie C.C.
        Mortality trends in men and women with diabetes, 1971 to 2000.
        Ann Intern Med. 2007; 147: 149-155
        • Alexander G.C.
        • Sehgal N.L.
        • Moloney R.M.
        • Stafford R.S.
        National trends in treatment of type 2 diabetes mellitus, 1994-2007.
        Arch Intern Med. 2008; 168: 2088-2094
      1. Red book: pharmacy’s fundamental reference, 2010 edition. New York: Thomson Reuters, 2010

        • National Center for Health Statistics
        National Health Interview Survey diabetes supplement.
        NCHS, Hyattsville MD2006
        • Nichols G.A.
        • Vupputuri S.
        • Lau H.
        Medical care costs associated with progression of diabetic nephropathy.
        Diabetes Care. 2011; 34: 2374-2378
        • NIH, National Institute of Diabetes and Digestive and Kidney Diseases
        USRDS 2012 annual data report: atlas of chronic kidney disease and end-stage renal disease in the U.S.
        US Renal Data System, Bethesda MD2012
        • O'Brien J.A.
        • Patrick A.R.
        • Caro J.J.
        Cost of managing complications resulting from type 2 diabetes mellitus in Canada.
        BMC Health Serv Res. 2003; 3: 7
        • Rein D.B.
        • Zhang P.
        • Wirth K.E.
        • et al.
        The economic burden of major adult visual disorders in the U.S.
        Arch Ophthalmol. 2006; 124: 1754-1760
        • Taylor T.N.
        • Davis P.H.
        • Torner J.C.
        • Holmes J.
        • Meyer J.W.
        • Jacobson M.F.
        Lifetime cost of stroke in the U.S.
        Stroke. 1996; 27: 1459-1466
        • Hogan C.
        • Lunney J.
        • Gabel J.
        • Lynn J.
        Medicare beneficiaries’ costs of care in the last year of life.
        Health Aff (Millwood). 2001; 20: 188-195
        • Brandle M.
        • Zhou H.
        • Smith B.R.
        • et al.
        The direct medical cost of type 2 diabetes.
        Diabetes Care. 2003; 26: 2300-2304
        • Caro J.J.
        • Ward A.J.
        • O'Brien J.A.
        Lifetime costs of complications resulting from type 2 diabetes in the U.S.
        Diabetes Care. 2002; 25: 476-481
        • Birnbaum H.
        • Leong S.
        • Kabra A.
        Lifetime medical costs for women: cardiovascular disease, diabetes, and stress urinary incontinence.
        Womens Health Issues. 2003; 13: 204-213
        • Goldman D.P.
        • Zheng Y.
        • Girosi F.
        • et al.
        The benefits of risk factor prevention in Americans aged 51 years and older.
        Am J Public Health. 2009; 99: 2096-2101
      2. CDC. National Diabetes Prevention Program. 2011 11/04/2011 [cited 2012 06/01/2012]. www.cdc.gov/diabetes/prevention/index.htm.

        • Knowler W.C.
        • Barrett-Connor E.
        • Fowler S.E.
        • et al.
        Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.
        N Engl J Med. 2002; 346: 393-403
        • Pan X.R.
        • Li G.W.
        • Hu Y.H.
        • et al.
        Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. The Da Qing IGT and Diabetes Study.
        Diabetes Care. 1997; 20: 537-544
        • Tuomilehto J.
        • Lindstrom J.
        • Eriksson J.G.
        • et al.
        Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance.
        N Engl J Med. 2001; 344: 1343-1350
        • Ali M.K.
        • Echouffo-Tcheugui J.
        • Williamson D.F.
        How effective were lifestyle interventions in real-world settings that were modeled on the Diabetes Prevention Program?.
        Health Aff (Millwood). 2012; 31: 67-75
        • Li R.
        • Zhang P.
        • Barker L.E.
        • Chowdhury F.M.
        • Zhang X.
        Cost-effectiveness of interventions to prevent and control diabetes mellitus: a systematic review.
        Diabetes Care. 2010; 33: 1872-1894
        • De Geest S.
        • Sabate E.
        Adherence to long-term therapies: evidence for action.
        Eur J Cardiovasc Nurs. 2003; 2: 323
        • Beckles G.L.
        • Engelgau M.M.
        • Narayan K.M.
        • Herman W.H.
        • Aubert R.E.
        • Williamson D.F.
        Population-based assessment of the level of care among adults with diabetes in the U.S.
        Diabetes Care. 1998; 21: 1432-1438
      3. CDC. National diabetes fact sheet. 2011. www.cdc.gov/diabetes/pubs/pdf/ndfs_2011.pdf.

        • Koopman R.J.
        • Mainous 3rd, A.G.
        • Diaz V.A.
        • Geesey M.E.
        Changes in age at diagnosis of type 2 diabetes mellitus in the United States, 1988 to 2000.
        Ann Fam Med. 2005; 3: 60-63
        • American Diabetes Association
        Implications of the United Kingdom Prospective Diabetes Study.
        Diabetes Care. 1998; 21: 2180-2184
        • American Diabetes Association
        Standards of medical care in diabetes—2010.
        Diabetes Care. 2010; 33: S11-61