Health-related quality of life in a randomised placebo-controlled trial of sibutramine in obese patients with type II diabetes

Abstract

Objective: We evaluated the effects of 12-month treatment with sibutramine 15 mg daily compared with placebo on health-related quality of life (HRQL) in obese type II diabetes patients. We examined the associations between the changes in HRQL and in weight, glycaemic control, and haemodynamic variables. We also explored the predictive value of HRQL and its changes early during treatment.

Design: A randomised clinical trial. The subjects were enrolled in a 2-week single-blind run-in period with a modestly hypocaloric diet (700 kcal daily deficit) and then randomised to receive either sibutramine 15 mg (n=114, 60% female) or placebo (n=122, 58% female) once daily with the hypocaloric diet for 12 months.

Subjects: Obese (mean BMI 36 kg/m(2) and age 54 y) type II diabetes patients untreated with antidiabetic medications.

Measurements: The main outcome measures included body weight and HRQL (the RAND 36-Item Health Survey 1.0).

Results: The mean weight loss was greater in the sibutramine group (-7.1 kg) than in the placebo group (-2.6 kg, P<0.001). The baseline HRQL was relatively high. There were no significant differences between the treatment groups in glycaemic control or in any of the RAND-36 scales during the study. The scores on physical functioning (PF) and health change (HC) since last year improved in both groups and this improvement was related to weight loss. When HRQL changes were examined in categories of weight loss, the scores on PF and HC increased with >/=5% weight loss, but the scores on vitality (V) and general health (GH) increased only after >/=15% weight loss. Decrease in HbA1c was associated with increases in the scores of PF, GH, V, mental health, and HC. In the sibutramine group, the increase in diastolic blood pressure was associated with the decrease in the scores of PF, physical role functioning, emotional role functioning (ERF), social functioning (SF), and bodily pain. High baseline scores on ERF and SF, and low scores on V predicted weight loss at 12 months. Also, increasing scores on PF and V during the first 3 months predicted weight loss at 12 months. The sum of four dichotomised HRQL variables (baseline ERF >/=75=1 and <75=0; baseline SF>/=80=1 and <80=0; 3-month change in PF>0=1 and </=0=0; 3-month change in V>0=1 and </=0=0) predicted weight loss: In the group with sum 0, the mean(s.d.) weight change at 12 months was 0.0(2.6)% and with sum 4 it was -9.0(8.1)% of baseline weight.

Conclusion: Despite the superior weight loss, sibutramine 15 mg daily did not produce HRQL benefits over placebo when measured with the generic RAND-36 in obese type II diabetes patients. PF and HC since last year improved with >/=5% weight loss, but >/=15% weight loss was needed to achieve a cluster of HRQL improvements. The decrease in HbA1c was associated with many HRQL benefits. Poor baseline HRQL and the improvement observed in the first months of treatment may prove to be useful in predicting success in long-term weight loss.