Cause-specific mortality in insulin-treated diabetic patients: a 20-year follow-up.
BACKGROUND
Diabetes is one of the most common chronic diseases in Western populations. There have been few large published cohort studies of diabetes with 20 years of follow-up worldwide, and none other than the present one in NZ.


OBJECTIVE
To establish cause-specific death rates, by age and sex in insulin-treated diabetic individuals living in Canterbury, NZ.


METHODS
Insulin-treated diabetic subjects on the Canterbury Diabetes Registry were followed over 20 years and vital status determined. Following notification of deaths, age- and sex-specific mortality rates, and sex-specific mortality ratios (SMRs) were calculated.


RESULTS
During follow-up 966 diabetic subjects contributed 13,495 person-years and 525 deaths occurred (261 females and 264 males). At all ages mortality rates were considerably higher than expected mortality. Relative mortalities were increased for cardiovascular (SMR women 3.73, 95% CI: 3.16-4.30; men 3.27, 95% CI: 2.76-3.78), renal (SMR women 5.55, 95% CI: 2.53-8.57; men 7.15, 95% CI: 3.40-10.90), respiratory disease (SMR women 3.31, 95% CI: 1.98-4.63; men 2.32, 95% CI: 1.41-3.23) and malignancy (SMR women 4.99, 95% CI: 2.99-6.99; men 2.19, 95% CI: 1.42-2.96) with cardiovascular disease accounting for the single greatest cause of excess death at all ages.


CONCLUSIONS
Mortality rates for diabetic individuals remain high, resulting in shortened life spans relative to the general population. To reduce these death rates attention must be paid to the early detection and treatment of CVD and associated risk factors.
Dawson
Shelagh I
SI
Centre for Postgraduate Nursing, Christchurch School of Medicine, University of Otago, New Zealand. shelagh.dawson@otago.ac.nz
Willis
Jinny
J
Florkowski
Christopher M
CM
Scott
Russell S
RS
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002318:Cardiovascular Diseases / Q000401:mortality*; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy* / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007223:Infant; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D012042:Registries / Q000706:statistics & numerical data; D017678:Sex Distribution
D007004:Hypoglycemic Agents; D007328:Insulin