In a study of obese adults, the lipase inhibitor orlistat was found to produce sustained weight loss and significantly affect glucose and insulin metabolism.
The study, conducted by Dr. Steven B. Heymsfield, of St. Luke's-Roosevelt Hospital in New York, and colleagues evaluated data from 675 obese adults from 39 sites in the US and Europe. After 4 weeks on a low-calorie diet, 359 subjects were randomized to receive orlistat, 120 mg t.i.d., and 316 were randomized to placebo. All subjects stayed on the low-calorie diet for 1 year, and those who continued followed a weight-maintenance diet in the second year.
At the study's onset, diabetes mellitus was diagnosed in 5.3% of subjects in the orlistat group and 4.4% of those in the placebo group. Impaired glucose tolerance was present in 18.7% and 16.8%, respectively.
The orlistat group experienced a greater weight loss over the course of the study than did the placebo group. The researchers note that there was a 6.8% weight change from initial body weight for the treatment group versus a 3.9% change for those on placebo.
The research team also found that of the subjects with impaired glucose tolerance at baseline, 71.6% of the orlistat patients had normal glucose tolerance at the end of treatment compared with 49.1% in the placebo group. Only 3.0% of the patients treated with orlistat progressed to diabetic status versus 7.6% in the placebo group.
Orlistat affected glycemic control beyond what weight loss alone would predict. The study concluded that pharmacologic treatment with orlistat may be a useful adjunct to dietary and lifestyle interventions in preventing or delaying the onset of glucose intolerance or type 2 diabetes in obese subjects.