Long-term cardiovascular and non-cardiovascular mortality in women and men with type 1 and type 2 diabetes mellitus: a 30-year follow-up in Switzerland

Abstract

Background: While studies from other countries have shown an excess mortality in diabetic individuals when compared with the general population, comparable long-term data is not available for Switzerland.

Aims: To assess gender-specific cardiovascular and non-cardiovascular mortality of patients with type 1 and type 2 diabetes compared with the general Swiss population between 1974 and 2005.

Design: 533 patients (225 type 1, 308 type 2 diabetes, 52.2% men) were followed for 30 years (10349 person-years).

Results: Diabetic patients had an increased all-cause mortality compared with the general population (SMR [95% CI] 3.8 [3.5-4.3]). Standardised mortality ratio (SMR) was higher for type 1 compared with type 2 diabetic patients (4.5 [3.8-5.3] vs 3.5 [3.1-4.0], p = 0.032). For cardiovascular and non-cardiovascular deaths SMRs were 5.6 (95% CI 4.8-6.6) and 2.7 (2.3-3.1) and did not differ according to type of diabetes. SMRs for all-cause and cardiovascular mortality were significantly higher in women compared with men in type 1 (p <0.05 and p <0.01) and type 2 diabetes (p <0.001 and p <0.01). In both types of diabetes, SMRs significantly decreased during the last two decades (p for trend 0.004 and 0.002).

Conclusions: Patients with type 1 and type 2 diabetes had an increased long-term mortality compared with the general Swiss population. Excess mortality was higher in type 1 compared with type 2 diabetes and in women compared with men for both types of diabetes, but steadily decreased over the last two decades.