Purpose: Data on cardiovascular outcomes among treated diabetics have been inconsistent. Our goal was to compare cardiovascular outcomes associated with different treatments for diabetes.
Methods: This is a retrospective cohort study of diabetic patients at least 40 years of age treated in general practices participating in The Health Information Network (THIN) data system between 2002 and 2006. Our primary outcome was serious atherosclerotic vascular disease of the heart.
Results: Among all diabetics (N = 63 579), the fully adjusted hazard ratios of association with our outcome were 1.2 (1.1, 1.3) for insulin, 1.03 (0.97, 1.09) for sulfonylureas, 0.8 (0.7, 0.8) for biguanide, 1.2 (0.99, 1.5) for meglitinide, 0.5 (0.5, 0.6) for thiazolidinediones, and individually 0.6 (0.5, 0.6) for rosiglitazone, and 0.5 (0.4, 0.7) for pioglitazone. Among those individuals newly diagnosed and treated for diabetes after 2002 (N = 13 576), the adjusted hazard ratios of association with our outcome were 2.4 (2.0, 2.9) for insulin, 1.4 (1.2, 1.7) for sulfonylureas, 0.5 (0.4, 0.5) for biguanide, 0.9 (0.4, 2.1) for meglitinide, 0.8 (0.7, 1.0) for thiazolidinediones, and individually 0.8 (0.6, 1.0) for rosiglitazone, and 0.9 (0.6, 1.4) for pioglitazone. Risk increased as total duration of therapy increased for insulin, sulfonylureas, and biguanide, but decreased with duration for rosiglitazone and pioglitazone.
Conclusions: Overall, insulin was associated with an increased risk of myocardial infarction. Its risk increased with longer use, and risk emerged with longer use of sulfonylureas and biguanide. Conversely, a protective effect emerged with longer use of rosiglitazone or pioglitazone.