Aims/hypothesis: The aim of this work was to analyse the rates of incidence and remission of type 2 diabetes in relation to baseline BMI and weight change in the prospective, controlled Swedish Obese Subjects (SOS) study.
Methods: Three-thousand four-hundred and eighty-five obese individuals receiving bariatric surgery or conventional treatment were grouped into four baseline BMI categories (<35, 35-40, 40-45 or ≥ 45 kg/m(2)) and five weight-change categories according to their BMI at 2 years (increase [≥ 1 BMI unit increase], no change [less than 1 BMI unit change], minor reduction [-1 to -9 BMI units], medium reduction [-10 to -14 BMI units] and major reduction [< -15 BMI units]). The incidence and remission of diabetes at 2 years was assessed.
Results: Among individuals with no weight change, diabetes incidence rates were 5.5%, 7.4%, 8.3% and 5.2%, in the four baseline BMI categories, respectively. In those with an initial BMI of 35-40, 40-45 and ≥ 45 kg/m(2) who attained a minor reduction in weight, the corresponding rates were 1.3%, 1.2% and 3.4%, respectively. In both the medium- and major-weight-reduction groups, diabetes incidence was ≤ 0.5%. Among individuals with diabetes at baseline, the remission rates were 15.3-26.9% in the no-weight-change groups, and 48.1-70% for individuals who attained a minor weight reduction. In the medium- and major-weight-reduction groups, the remission rate was 77-97%. There were no differences in 2 year incidence and remission rates between different baseline BMI groups that achieved the same degree of weight reduction.
Conclusions/interpretation: In obese individuals, the favourable effect of weight reduction on type 2 diabetes incidence and remission is independent of initial BMI. Trial registration ClinicalTrials.gov number NCT01479452.