Predictors of health care costs in adults with diabetes

OBJECTIVE - The purpose of this study was to assess the impact of baseline Alc, cardiovascular disease, and depression on subsequent health care costs among adults with diabetes. RESEARCH DESIGN AND METHODS - A prospective analysis was performed of data from a patient survey and medical record review merged with 3 years of medical claims. Costs were estimated using detailed data on resource use and Medicare payment methodologies. Generalized linear models were used to analyze costs related to clinical predictors after adjusting for demographic and socioeconomic factors. RESULTS - In multivariate analysis of 1,694 adults with diabetes, 3-year costs in those with coronary heart disease (CHD) and hypertension were over 300% of those with diabetes only ($46,879 vs. $14,233; P < 0.05). Depression was associated with a 50% increase in costs ($31,967 vs. $21,609; P < 0.05). Relative to those with a baseline Alc of 6%, those with an Alc of 70% had 3-year costs that were 11% higher ($26,408 vs. $23,873; P < 0.05). Higher Alc predicted higher costs only for those with baseline Alc >7.5% (P = 0.015). CONCLUSIONS - In adults with diabetes, CHD, hypertension, and depression spectrum disorders more strongly predicted future costs than the Alc level. Concurrent with aggressive efforts to control glucose, greater efforts to prevent or control CHD, hypertension, and depression are necessary to control health care costs in adults with diabetes. Diabetes Care 28:59-64, 2005.