The British Diabetic Association Cohort Study, I: all-cause mortality in patients with insulin-treated diabetes mellitus

Summary Aims To assess mortality in patients with diabetes incident under the age of 30 years. Methods A cohort of 23 752 diabetic patients diagnosed under the age of 30 years from throughout the United Kingdom was identified during 1972–93 and followed up to February 1997. Following notification of deaths during this period, age‐ and sex‐specific mortality rates, attributable risks and standardized mortality rates were calculated. Results The 23 752 patients contributed a total of 317 522 person‐years of follow‐up, an average of 13.4 years per subject. During follow‐up 949 deaths occurred in patients between the ages of 1 and 84 years, 566 in males and 383 in females. All‐cause mortality rates in the patients with diabetes exceeded those in the general population at all ages and within the cohort were higher for males than females at all ages except between 5 and 15 years. The relative risk of death (standardized mortality ratio, SMR), was higher for females than males at all ages, being 4.0 (95% CI 3.6–4.4) for females and 2.7 (2.5–2.9) for males overall, but reaching a peak of 5.7 (4.7–7.0) in females aged 20–29, and of 4.0 (3.1–5.0) in males aged 40–49. Attributable risks, or the excess deaths in persons with diabetes compared with the general population, increased with age in both sexes. Conclusions This is the first study from the UK of young patients diagnosed with diabetes that is large enough to calculate detailed age‐specific mortality rates. This study provides a baseline for further studies of mortality and change in mortality within the United Kingdom.