Obesity, weight loss and prognosis in type 2 diabetes.

Medical records were reviewed of all 263 Type 2 diabetic patients from the Aberdeen diabetic clinic who were known to have died in 1985 or 1986. Mean age was 65 years (interquartile range 57-75 years) at diagnosis and 72 (66-80) years for men, 75 (72-83) years for women, at death. Life expectancy at age 65 was 35% less than published figures for the general population. Analysis of survival in 233 patients who lived more than 1 year (189 overweight) using stepwise multiple regression indicated as significant (p less than 0.05) adverse independent variables: age at diagnosis, presence of clinical ischaemic heart disease at diagnosis, plasma glucose at diagnosis; and as significant favourable variables: oral hypoglycaemic drug therapy, weight loss in the first year, and an interaction between weight loss and BMI for patients with BMI greater than 25 kg m-2. Changes in fashions over the years are likely to have biased these results towards including oral hypoglycaemic therapy and excluding the expected adverse effect of smoking. Mean weight loss at 1 year was 2.6 kg for those with BMI 25-30 kg m-2, 6.8 kg with BMI greater than 30 kg m-2, following standard dietetic advice. For the average patient each 1 kg weight loss was associated with 3-4 months prolonged survival.