Causes of the change in the rates of mortality and severe complications of diabetes mellitus: 1992-2012.

OBJECTIVE: To quantify the causes of the changes in the rates of mortality and select severe complications of diabetes mellitus, type 2 (T2D) among the elderly between 1992 and 2012. RESEARCH DESIGN: A retrospective cohort study design based on Medicare 5% administrative claims data from 1992 to 2012 was used. Traditional fee-for-service Medicare beneficiaries, age 65 and older, diagnosed with T2D and living in the United States between 1992 and 2012 were included in the study. Blinder-Oaxaca decomposition was used to quantify the potential causes of the change in the rates of death, congestive heart failure and/or acute myocardial infarction, stroke, amputation of lower extremity and end-stage renal disease between 1992 and 2012. RESULTS: The number of beneficiaries in the analysis sample diagnosed with T2D increased from 152,191 in 1992 to 289,443 in 2012. Over the same time period, rates of mortality decreased by 1.2, congestive heart failure and/or acute myocardial infarction by 2.6, stroke by 1.6, amputation by 0.6 while rates of end-stage renal disease increased by 1.5 percentage points. Improvements in the management of precursor conditions and utilization of recommended healthcare services, not population composition, were the primary causes of the change. CONCLUSIONS: With the exception of end-stage renal disease, outcomes among Medicare beneficiaries diagnosed with T2D improved. Analysis suggests that persons diagnosed with T2D are living longer with fewer severe complications. Much of the improvement in outcomes likely reflects more regular contact with health professionals and better management of care.