Association between glycosylated hemoglobin and intentional weight loss in overweight and obese patients with type 2 diabetes mellitus: a retrospective cohort study.

PURPOSE

The purpose of this study is to assess the relationship between magnitude of weight loss and improvement in percentage A1C (A1C%) among overweight and obese patients with type 2 diabetes mellitus (DM) undergoing weight reduction.

METHODS

Case records of patients enrolled in 2 university-based weight management programs were reviewed. Patients were sampled if they had a diagnosis of DM and had at least 1 documented A1C% reduction from their baseline value. Weight loss treatment was individualized and consisted of a calorie-restricted diet, a behavior modification plan, and a plan for increasing physical activity. Patient weights were measured at bimonthly visits. A1C% was measured every 3 months.

RESULTS

Seventy-two patients formed the study cohort. Mean baseline body mass index was 35.1 kg/m(2), mean age was 52.6 years, and 59% were males. Mean starting A1C% was 8.6. Patients achieved significant mean weight loss (10.7 kg) at study exit. Weight loss of 6.5 kg (4.5% of baseline body weight), 12.2 kg (8.7%), and 15.9 kg (10.3%) was required to reduce A1C% by 0.5, 1, and 1.5, respectively, and it took a mean of 5.6, 8.7, and 10.1 months, respectively, to achieve this. After adjustment for antidiabetic medication intake, for every 10% weight loss, the predicted reduction in A1C% was 0.81.

CONCLUSIONS

Intentional weight loss of 10% can potentially decrease A1C% by 0.81 among patients with type 2 DM. This finding may be clinically useful in encouraging and counseling a patient attempting weight loss.