Predictors of mortality from type 2 diabetes mellitus in Canterbury, New Zealand; a ten-year cohort study

The aim was to establish mortality rates in a cohort of subjects with type 2 diabetes mellitus over 10 years in Canterbury, New Zealand (NZ) and to de termine baseline prognostic factors. Subjects (447) with type 2 diabetes (2 08 male, 239 female; age range 30-82 years, median 62 years; of predominant ly European origin) were characterised in a clinic survey in 1989. individu al status (dead or alive) at June 1 1999(10 year follow-up) was ascertained . Mortality rates were compared with the general NZ population and the rela tive risk (RR) of baseline prognostic factors evaluated with Cox's proporti onal hazards model. At 10 years, 232 subjects were confirmed as alive and 1 87 as dead-only 28 were untraceable. Ten year survival was 55% (95% CI: 50- 60) for the cohort, compared with 70% (95% CI: 65-75) at 6 years. Factors a ssessed at baseline (1989), that were independently prognostic of total mor tality, included age (RR 2.0, 95% CI: 1.6-2.5), pre-existing coronary arter y disease (CAD; RR 1.7, 95% CI: 1.2-2.4) and albuminuria (RR 1.58, 95% CI: 1.1 2.3). Glycated haemoglobin was not a significant predictor of total mor tality, although was a predictor of CAD mortality in those subjects free of CAD in 1989 (RR 1.6. 95% CI: 1.1-2.3). In the latter subset, independent p rognostic factors for CAD mortality also included age (RR 2.5, 95% CI: 1.7- 3.8), hypertension (RR 1.9, 95% CI: 1.0-3.7), peripheral vascular disease ( RR 2.4, 95% CI 1.3-4.5) and smoking (RR 2.6, 95% CI: 1.7-5.8). Increased mo rtality in type 2 diabetic subjects is therefore attributable to multiple r isk factors. Improved outcomes will depend on interventions targeted at gly caemic and all other remediable factors. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.