The economic costs of undiagnosed diabetes.

The objective is to estimate the national economic costs associated with undiagnosed diabetes mellitus (UDM). UDM is defined as unknowingly having an elevated glucose level that meets the definition of diabetes. National Health and Nutrition Examination Survey (NHANES) data are used to estimate the prevalence of UDM. Because UDM cannot be directly observed in medical claims for analyzing per capita patterns of health care use, we analyze annual medical claims from a proxy population--people within 2 years of first diagnosis of diabetes. For a commercially insured population first diagnosed with diabetes in 2006 (n = 29,770), we compare their annual health care use in 2004 and 2005 to that of patients with no history of diabetes between 2004 and 2006 (n = 3.2 million). We combine estimates of UDM prevalence from NHANES with health care use patterns from the proxy population to estimate etiological fractions that reflect the portion of national health care use associated with UDM. Approximately 6.3 million adults in the United States have UDM in 2007. Annual per capita use of health care services for the UDM proxy population is higher than for a comparable group with no history of diabetes, but lower than for a comparable group with a history of diabetes. The estimated economic costs of UDM in 2007 is $18 billion ($2864 per person with UDM), including medical costs of $11 billion and indirect costs of $7 billion. Although the high prevalence of UDM makes it an important health issue to be studied, data limitations have contributed to a dearth of information on the health care use patterns and economic costs of UDM. By omitting UDM, estimates of the total national cost of diabetes are underestimated.

Distinguishing the economic costs associated with type 1 and type 2 diabetes.

The objective was to estimate the economic costs of diagnosed type 1 (T1DM) and type 2 (T2DM) diabetes mellitus in the United States in 2007. Medical claims were analyzed to estimate the proportion of diagnosed diabetes cases and excess medical costs by diabetes type. Indirect costs associated with T1DM and T2DM were estimated by using findings from the literature on diagnosed diabetes, as well as differences in health per case of T1DM and T2DM. This study builds on the Cost of Diabetes Model developed for the American Diabetes Association to estimate the economic burden of diagnosed diabetes. T1DM accounts for an estimated 5.7% (1.0 million) of the 17.5 million people with diagnosed diabetes. Approximately $14.9 billion (8.6%) of the economic burden of diagnosed diabetes is associated with T1DM, including medical costs of $10.5 billion and indirect costs of $4.4 billion. Costs associated with T2DM are $159.5 billion, including medical costs of $105.7 billion and indirect costs of $53.8 billion. The economic burden per case of diabetes is greater for T1DM than for T2DM, and the difference increases with age. The prevalence of T2DM is significantly greater than the prevalence of T1DM, so T2DM is responsible for most of the economic burden of diabetes. Estimates for T1DM are sensitive to the criteria used to identify people with diabetes using claims data; estimates for T2DM are relatively stable. Improved coding of diabetes type in medical claims and identification of diabetes type in survey data could lead to more precise estimates of the economic burden by diabetes type.