Comparison of Efficacy of Metformin in Obese and Non-Obese Women with Polycystic Ovary Syndrome (PCOS)

Abstract

Background: Polycystic ovary syndrome is a common endocrine disorder of reproductive-age women and is frequently associated with obesity, insulin resistance, and ovulatory dysfunction. Obesity may modify therapeutic response to metformin, but existing evidence remains inconsistent. Objective: To determine the frequency of obesity among women with polycystic ovary syndrome and to compare the efficacy of metformin between obese and non-obese women. Methods: This hospital-based analytical observational study was conducted in the Department of Obstetrics and Gynecology, Bolan Medical Complex Hospital, Quetta, from 15 October 2024 to 16 April 2025. A total of 300 women aged 18 to 40 years with polycystic ovary syndrome received metformin 1500 mg daily in three divided doses for three months. Obesity was defined as body mass index at least 30 kg/m². Efficacy was assessed as ovulatory response after treatment completion. Comparative analysis was performed using the chi-square test with stratification by age and disease duration. Results: The mean age was 27.4±5.4 years and the mean disease duration was 12.2±3.9 months. Obesity was present in 170 women (56.7%). Overall metformin efficacy was observed in 140 women (46.7%). Efficacy was significantly lower in obese women than in non-obese women (35.3% vs 61.5%; p=0.001). This difference remained significant across age and disease-duration subgroups. Conclusion: Obesity was common in women with polycystic ovary syndrome and was associated with markedly reduced short-term metformin efficacy. Routine BMI assessment and early weight-focused management may improve treatment planning and counseling in this population