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 < 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 > 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 > 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.