Detecting type 2 diabetes and prediabetes among asymptomatic adults in the United States: modeling American Diabetes Association versus US Preventive Services Task Force diabetes screening guidelines.

BACKGROUND: Screening to detect prediabetes and diabetes enables early prevention and intervention. This study describes the number and characteristics of asymptomatic, undiagnosed adults in the United States who could be detected with prediabetes and type 2 diabetes using the American Diabetes Association (ADA) guidelines compared to the United States Preventive Services Task Force (USPSTF) guidelines. METHODS: We developed predictive models for undiagnosed diabetes and prediabetes using polytomous logistic regression from data on risk factors in the 2003-2010 National Health and Nutrition Examination Survey (n = 19,056). We applied these predictive models to the 2010 Medical Expenditure Panel Survey, which contains health care use data, to generate probabilities of undiagnosed diabetes and undetected prediabetes for each adult. We summed individual probabilities to estimate the number of adults who would be detected with prediabetes and/or type 2 diabetes if screened under ADA or USPSTF guidelines. We analyzed health care use patterns of people at high risk for diabetes. RESULTS: In 2010, 59.1 million adults met the USPSTF screening criteria including 24.4 million people with undetected prediabetes and 3.7 million people with undiagnosed diabetes. In comparison, among the 86.3 million people who met the ADA screening criteria, there were 33.9 million with undetected prediabetes and 4.6 million with undiagnosed type 2 diabetes. The ADA guidelines detected 38.9% more cases of prediabetes and 24.3% more cases of type 2 diabetes compared to the USPSTF guidelines. Subgroup analysis showed that ADA guidelines would detect 78% more cases of diabetes among the age 54 and younger population, in 40% more blacks, and in more than twice as many Hispanics than USPSTF guidelines. Only 58% of adults meeting ADA guidelines and 70% meeting USPSTF guidelines had ≥ 1 primary care office visit in 2010. CONCLUSIONS: Compared to USPSTF guidelines, ADA guidelines would screen more people and detect more cases of both prediabetes and type 2 diabetes, though a substantial percentage of patients with undetected cases had no contact with a primary care provider in 2010. Addressing the problem of large numbers of undetected prediabetes and type 2 diabetes cases will require new strategies for screening.

The economic burden of diabetes.

New research provides revised comprehensive estimates that suggest that the U.S. national economic burden of pre-diabetes and diabetes reached $218 billion in 2007. This estimate includes $153 billion in higher medical costs and $65 billion in reduced productivity. The average annual cost per case is $2,864 for undiagnosed diabetes, $9,975 for diagnosed diabetes ($9,677 for type 2 and $14,856 for type 1), and $443 for pre-diabetes (medical costs only). For each American, regardless of diabetes status, this burden represents a cost of approximately $700 annually. These results underscore the urgency of better understanding how prevention and treatment strategies may or may not help reduce costs.

Medical cost associated with prediabetes.

In this article, we estimate national health care resource use and medical costs in 2007 associated with prediabetes (PD), defined as either fasting plasma glucose between 100 and 125 or oral glucose tolerance test between 140 and 200. We use Poisson regression with medical claims for an adult population continuously insured between 2004 and 2006 to analyze patterns of health care resource use by PD status. Combining rate ratios that reflect health care use patterns with national PD prevalence rates from the National Health and Nutrition Examination Survey, we calculate etiological fractions to estimate the portion of national health resource use associated with PD. The findings suggest that PD is associated with statistically higher rates of ambulatory visits for hypertension; endocrine, metabolic, and renal complications; and general medical conditions. PD is associated with a slight increase in visit rates for neurological symptoms, peripheral vascular disease, and cardiovascular disease, but the increase is not statistically significant. There is no indication that PD is associated with an increase in emergency visits and inpatient days. Extrapolating these patterns to the 57 million adults with PD in 2007 suggests that national annual medical costs of PD exceed $25 billion, or an additional $443 for each adult with PD. PD is associated with excessive use of ambulatory services for comorbidities known to be related to diabetes. Our findings strengthen the business case for lifestyle interventions to prevent diabetes by adding additional economic benefits that potentially can be achieved by preventing or delaying PD.

Cost of gestational diabetes mellitus in the United States in 2007.

The objective of this study was to estimate the national medical costs associated with gestational diabetes mellitus (GDM) in 2007. We analyzed the National Hospital Discharge Survey to estimate the national prevalence of GDM. Using Poisson regression analysis with medical claims for about 27,000 newborns and their mothers, we estimated rate ratios that reflect the increase in use of health care services associated with GDM. Combining GDM prevalence rates with these rate ratios, we calculated etiological fractions that reflect the proportion of national health care resource use associated with GDM. We then multiplied these fractions by estimates of national health care use and costs in 2007. GDM prevalence increases with age, rising from 1.3% of pregnancies of women younger than age 21 to 8.7% of pregnancies of women older than age 35. For the estimated 180,000 GDM pregnancies resulting in delivery, average expenditures increased $3,305 per pregnancy plus $209 in the newborn's first year of life. GDM increased national medical costs by $636 million in 2007-$596 million for maternal costs and $40 million for neonatal costs. Approximately $230 million (36%) of GDM-related medical costs are covered by government programs (primarily Medicaid), $355 million (56%) are covered by private insurers, and $51 million (8%) are covered by self-pay and charity care. GDM imposes a significant economic burden. These estimates of the economic burden of GDM are likely conservative because we focus on near-term medical costs, omitting the increased risk for long-term sequelae.

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.