Temporal Trends in Cardiovascular Complications in People With or Without Type 2 Diabetes: The Fremantle Diabetes Study

Abstract

Context: There is evidence that diabetes-related complications are declining but most data sources have limitations.

Objective: To characterize temporal changes in incidence rates (IRs) of chronic complications and mortality in well-characterized, community-based Australians.

Design: Longitudinal observational study.

Setting: Urban population.

Participants: Participants with type 2 diabetes from the Fremantle Diabetes Study phases I (FDS1; n = 1291 recruited 1993-1996) and II (FDS2; n = 1509 recruited 2008-2011) age-, sex,- and ZIP code-matched 1:4 to people without diabetes.

Main outcome measures: First hospitalizations for/with myocardial infarction (MI), stroke, heart failure (HF), lower extremity amputation, and cardiovascular disease (CVD) and all-cause mortality. Five-year IRs, IR ratios for those with versus without diabetes in FDS1 and FDS2, and IR differences (IRDs), were calculated.

Results: The 13,995 participants had a mean age of 64.8 years and 50.4% were males. There were lower IR ratios for MI, stroke, HF, and CVD death in FDS2 versus FDS1. IRDs for people with versus without type 2 diabetes had reduced by >50% between phases for MI, stroke, HF, lower extremity amputation, and CVD death, with no change in IRD for all-cause mortality. Within the pooled type 2 diabetes cohort, FDS2 versus FDS1 participation was an independent inverse predictor of stroke, HF, CVD death, and all-cause mortality after adjustment in Cox proportional hazards models.

Conclusions: Cardiovascular outcomes in Australians have improved since the 1990s, especially in type 2 diabetes. The difference in all-cause mortality between those with and without type 2 diabetes has persisted despite longer survival.

Keywords: cardiovascular disease; community-based; longitudinal study; mortality; temporal trends; type 2 diabetes.