Introduction: Our aim was to evaluate the effects of metformin and orlistat
on body composition and glucose–insulin homeostasis in obese premenopausal
women.
Material and methods: Seventy-three obese premenopausal Caucasian
women aged 32.4 ±8.3 years were treated with either metformin (1000 mg/
day; n = 37) or orlistat (360 mg/day; n = 36). Anthropometric parameters
were measured using dual-energy X-ray absorptiometry. Glucose tolerance,
using the oral glucose tolerance test; insulin resistance, using the homeostasis
model assessment (HOMA-IR); and insulin sensitivity, using the Matsuda
insulin sensitivity index (ISI Matsuda), were assessed at the commencement
of the study and after 3 months.
Results: Those treated with orlistat showed greater weight loss (–9.4 ±2.3 vs.
–4.9 ±1.3 kg, p < 0.05) and decrease of fat mass (–5.4 ±3.0 vs. –3.5 ±0.7 kg,
p < 0.05) than those treated with metformin. The percentage of android and
gynoid fat deposits was reduced in both groups; however, a greater decrease
in android fat was observed in those treated with metformin. Improvement
in ISI Matsuda and post-load insulin were similar in both groups. High initial
post-load insulin and low ISI Matsuda corresponded with reductions in total
fat, trunk fat, and waist circumference in both groups, and a decrease in
android fat in those treated with metformin.
Conclusions: Orlistat treatment resulted in greater weight loss and improvement
in body composition; metformin treatment resulted in a reduction of
android fat. Both drugs produced a comparable improvement in insulin/glucose
homeostasis. Overall, insulin-resistant women showed improvement
with treatment, irrespective of which drug was used.
