The effects of orlistat in patients with diabetes: improvement in glycaemic control and weight loss.

OBJECTIVE

In addition to direct weight reduction, there may be other benefits of obesity treatment including improved insulin sensitivity. The purpose of this study was to characterise concomitant diabetes drug use and the related costs in patients with diabetes treated with orlistat (Xenical) in the first 6 months of treatment.

METHODS

One hundred overweight patients with diabetes and a body mass index (BMI) > or = 28 kg/m2 were enrolled in a structured UK hospital-based weight management clinic and treated with orlistat plus behavioural interventions. Among other measures, weight, glucose control (HbA1c) and drug treatment were recorded. Subjects were followed-up for a maximum of 24 months at intervals of 1-3 months, with a maximum treatment period of 24 months.

RESULTS

The majority of subjects (91%) had type 2 diabetes. They had a mean age of 55 years and 55% were women. For patients followed up at 6 months, their mean BMI at baseline was 39.5 kg/m2 with a mean HbA1c of 7.6%. The mean weight loss at 6 months was 7.1 kg (p < 0.001). Despite a significant average absolute HbA1c reduction of 0.62% (p < 0.001), the most notable gains were made by those with the highest baseline HbA1c values (a mean relative reduction of 20% for those above the 75th percentile). There were 50 patients treated with insulin at baseline and 47 at 6 months. Of those treated with insulin, the mean dose was 130 units at baseline and 90 units at 6 months (p < 0.001). Twenty patients (44.4%) initially treated with oral hypoglycaemic agents alone reduced their dose after 6 months (not significant). Despite marked improvement in insulin sensitivity (baseline mean, 1.24 units/kg; 6 month mean, 0.90 units/kg [p < 0.001]) there was no correlation with BMI change. The average cost of diabetes treatment at baseline was pound 1.16 per day and pound 0.83 at 6 months (p < 0.001). Age was the only independent predictor for insulin dose reduction.

CONCLUSIONS

Orlistat appears to reduce the need for concomitant diabetes medication irrespective of weight loss, a reduction that is likely to represent a large cost offset for orlistat treatment.