The Burden of Type 1 Diabetes

The Burden of Type 1 Diabetes

Epidemiology

Overall, type 1 diabetes (T1D) accounts for approximately 5% of diabetes and affects about 20 million individuals worldwide. Among those younger than 20 years of age, T1D accounts for the majority of T1D cases (1,2). The current U.S. prevalence estimate of 1-3 million T1D patients may triple by 2050 due to a rising incidence of T1D (3).

Worldwide, T1D incidence has been rising by approximately 3% per year (1,4), possibly in association with changes in the humoral autoimmune response to islet antigens (5). Other factors implicated in the rising incidence include early childhood infections, dietary protein makeup, insulin resistance, and inflammatory factors (6,7).

Morbidity and Mortality
Diabetic complications—retinopathy, nephropathy, neuropathy, and cardiovascular disease (CVD)—are the major causes of morbidity and mortality in persons with T1D, although severe hypoglycemia and diabetic ketoacidosis (DKA) are also associated with high mortality rates, particularly in younger patients (5-10).

Although the role of glucose control in reducing the risk of diabetes complications is well-established (11,12), real-world data show that rates of complications remain high, particularly in patients with suboptimal control. An analysis of the Diabetic Control and Complications Trial (DCCT) and Pittsburgh Epidemiology of Diabetes Complications (EDC) study populations revealed that the 30-year cumulative incidence of retinopathy was 50% among DCCT patients randomly assigned conventional therapy at the start of that trial, while the observational EDC study population had a 47% cumulative incidence over 30 years. Nephropathy rates were 25% and 17% in the DCCT-conventional and EDC cohorts, respectively, and 14% of patients had CVD in these two groups. In contrast, 30-year the cumulative incidences of retinopathy, nephropathy, and CVD were 27%, 9%, and 9%, respectively, among patients originally assigned to intensive therapy in the DCCT (9).

Costs
The economic burden per case of diabetes is greater for T1D than for type 2 diabetes T2D. Recent data from a nationally representative cost of illness study suggest that annual direct medical expenses and indirect costs such as lost income amount to $14.4 billion. Table 1 shows the expected lifetime costs for patients newly diagnosed with T1D. Although overall costs decrease with increasing age of diagnosis, total medical costs of $3 billion and $7 billion in lost income are expected over the lifetimes of the 28,430 patients included in the estimate (13).

Table 1. Expected Lifetime Medical and Indirect Costs Among a Cohort of Patients Newly Diagnosed with T1D (2005 U.S. dollars) (13)

Age of Onset

Number of New Patients

Medical
(millions)

Income Loss
(millions)

3-9

6483

$746

$1208

10-19

11,980

$1489

$2923

20-29

3528

$337

$1130

30-39

3976

$395

$1279

40-45

2464

$309

$776

Total

28,430

$3276

$7316

References

  1. International Diabetes Federation. Diabetes Atlas. 6th ed. Brussels, Belgium: International Diabetes Federation; 2013.
  2. Menke A, Orchard TJ, Imperatore G, Bullard KM, Mayer-Davis E, Cowie CC. The prevalence of type 1 diabetes in the United States. Epidemiology. 2013;24:773-4.
  3. Imperatore G, Boyle JP, Thompson TJ, Case D, Dabelea D, Hamman RF, et al. Projections of type 1 and type 2 diabetes burden in the U.S. population aged <20 years through 2050: dynamic modeling of incidence, mortality, and population growth. Diabetes Care. 2012;35:2515-20.
  4. Tuomilehto J. The emerging global epidemic of type 1 diabetes. Curr Diab Rep. 2013;13:795-804.
  5. Long AE, Gillespie KM, Rokni S, Bingley PJ, Williams AJ. Rising incidence of type 1 diabetes is associated with altered immunophenotype at diagnosis. Diabetes. 2012;61:683-6.
  6. Forlenza GP, Rewers M. The epidemic of type 1 diabetes: what is it telling us? Curr Opin Endocrinol Diabetes Obes. 2011;18:248-51.
  7. Classen JB. Review of evidence that epidemics of type 1 diabetes and type 2 diabetes/metabolic syndrome are polar opposite responses to iatrogenic inflammation. Curr Diabetes Rev. 2012;8:413-8.
  8. Lind M, Svensson AM, Kosiborod M, Gudbjornsdottir S, Pivodic A, Wedel H, et al. Glycemic control and excess mortality in type 1 diabetes. N Engl J Med. 2014;371:1972-82.
  9. Nathan DM, Zinman B, Cleary PA, Backlund JY, Genuth S, Miller R, et al. Modern-day clinical course of type 1 diabetes mellitus after 30 years' duration: the diabetes control and complications trial/epidemiology of diabetes interventions and complications and Pittsburgh epidemiology of diabetes complications experience (1983-2005). Arch Intern Med. 2009;169:1307-16.
  10. Miller KM, Foster NC, Beck RW, Bergenstal RM, DuBose SN, DiMeglio LA, et al. Current state of type 1 diabetes treatment in the U.S.: updated data from the T1D Exchange clinic registry. Diabetes Care. 2015;38:971-8.
  11. Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993;329:977-86.
  12. Nathan DM, Cleary PA, Backlund JY, Genuth SM, Lachin JM, Orchard TJ, et al. Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes. N Engl J Med. 2005;353:2643-53.
  13. Tao B, Pietropaolo M, Atkinson M, Schatz D, Taylor D. Estimating the cost of type 1 diabetes in the U.S.: a propensity score matching method. PLoS One. 2010;5:e11501.