A diabetes epidemic emerged during the 20th century and continues unchecked into the 21st century. It has already taken an extraordinary toll on the U.S. population through its acute and chronic complications, disability, and premature death. Trend data suggest that the burden will continue to increase. Efforts to pre- vent or delay the complications of diabetes or, better yet, to prevent or delay the development of diabetes itself are urgently needed.

The objective of this study was to develop and validate a method for identifying Medicare beneficiaries with diabetes by using Medicare claims data. We used self-reports of diabetes status from participants in the Medicare Current Beneficiary Survey to determine disease status, and then we examined these participants' Medicare claims. Using self-reported diabetes status as the "gold standard," we determined the sensitivity, specificity, and reliability of claims data in identifying beneficiaries with diabetes. We found that to construct a method that is adequately sensitive (> or = 70%), highly specific (> or = 97.5%), and reliable (kappa > or = 0.80), researchers must combine information from different types of Medicare claims files, use 2 years of data to identify cases, and require at least 2 diagnoses of diabetes among claims involving ambulatory care. Since these criteria are met by more than one method, the choice of method should be governed by the goals of the research as well as more practical concerns.

OBJECTIVE -To examine racial/ethnic and economic variation in cost-related medication underuse among insured adults with diabetes.RESEARCH DESIGN AND METHODS -We surveyed 5,086 participants from the multicenter Translating Research Into Action for Diabetes Study. Respondents reported whether they used less medication because of cost in the past 12 months. We examined unadjusted and adjusted rates of cost-related medication underuse, using hierarchical regression, to determine whether race/ethnicity differences still existed after accounting for economic, health, and other demographic variables.RESULTS -Participants were 48% white, 14% African American, 14% Latino, 15% Asian/ Pacific Islander, and 8% other. Overall, 14% reported cost-related medication underuse. Unadjusted rates were highest for Latinos (23%) and African Americans (17%) compared with whites (13%), Asian/Pacific Islanders (11%), and others (15%). In multivariate analyses, race/ethnicity significantly predicted cost-related medication underuse (P ϭ 0.048). However, adjusted rates were only slightly higher for Latinos (14%) than whites (10%) (P ϭ 0.026) and were not significantly different for African Americans (11%), Asian/Pacific Islanders (7%), and others (11%). Income and out-of-pocket drug costs showed the greatest differences in adjusted rates of cost-related medication underuse (15 vs. 5% for participants with income Յ$25,000 vs. Ͼ$50,000 and 24 vs. 7% for participants with out-of-pocket costs Ͼ$150 per month vs. Յ$50 per month.CONCLUSIONS -One in seven participants reported cost-related medication underuse. Rates were highest among African Americans and Latinos but were related to lower incomes and higher out-of-pocket drug costs in these groups. Interventions to decrease racial/ethnic disparities in cost-related medication underuse should focus on decreasing financial barriers to medications. Diabetes Care 31:261-266, 2008

OBJECTIVE -To estimate the prevalence of physical limitations associated with diabetes among U.S. adults Ն18 years of age.RESEARCH DESIGN AND METHODS -We conducted a cross-sectional analysis of the association between diabetes status and physical limitations using the 1997-1999 National Health Interview Survey (NHIS). Physical limitation was defined from self-reported degree of difficulty with nine tasks.RESULTS -People with diabetes had a higher proportion of any physical limitation than did people without diabetes overall (66 vs. 29%, P Ͻ 0.001), for both men (59 vs. 24%, P Ͻ 0.001) and women (72 vs. 34%, P Ͻ 0.001). Compared with those without diabetes, a higher proportion of people with diabetes had some physical limitation among all age groups, and the difference declined (all P Ͻ 0.001) with increasing age (46 vs. 18% for 18 -44 years, 63 vs. 35% for 45-64 years, 74 vs. 53% for 65-74 years, and 85 vs. 70% for those 75 years and older). After controlling for demographic characteristics and several other confounders, the odds ratio of physical limitation among adults with diabetes versus those without diabetes was 1.9 (95% CI: 1.8 -2.1).CONCLUSIONS -People with diabetes are much more likely to have a physical limitation than those without diabetes. Interventions are needed in this population to reduce progression from impairment to physical limitation and from physical limitation to disability, especially because the prevalence of diabetes is projected to increase dramatically in the next several decades.