All-cause mortality in insulin-treated diabetic patients: a 20-year follow-up

Abstract

Aims: To establish all-cause mortality rates, and risk factors for mortality in insulin-treated diabetic individuals living in Canterbury, New Zealand.

Methods: Insulin-treated diabetic subjects (n=995) on the Canterbury Diabetes Registry were followed up over 20-year and vital status determined. Death rates were standardised and hazard regression was used to model the effects of demographic covariates on relative survival time.

Results: Six subjects had emigrated, the remaining 989 diabetic subjects contributed a total of 13705.53 person-years of follow-up, a mean of 13.7 years per subject. During follow-up 525 deaths occurred in subjects' aged 17.3-96.7, (261 females, 264 males). All-cause mortality rates in diabetic subjects exceeded those in the general population at all ages. SMRs were slightly higher for females than males in almost all age-at-onset groups, being 2.48 (95% CI: 2.18-2.78) for females and 2.17 (95% CI: 1.91-2.43) for males overall, but reaching a peak in the <30 age at onset group for both females and males being 4.25 (3.07-5.44) and 3.26 (2.49-4.03), respectively.

Conclusions: Mortality rates for diabetic individuals remain high, resulting in shortened life spans relative to the general population. This study provides a baseline for further studies of mortality and changes in mortality within New Zealand.