Comparison of metformin with inositol versus metformin alone in women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials

Abstract

Purpose: Metformin was the first medication targeting insulin resistance in PCOS, and it has been extensively studied as a metabolic treatment option. In recent years, inositols have emerged as potential treatment options for PCOS, but confidence in the available evidence supporting their use is limited.

Methods: We comprehensively searched PubMed, Embase, and Cochrane databases for RCTs comparing the use of combined metformin and inositol versus metformin alone in women with PCOS. A random-effects model was used to calculate the risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs). A p-value of <0.05 was deemed as statistically significant.

Results: Six RCTs and 388 patients were included in the analysis, with follow-up ranging from 3 to 6 months. Combination therapy was significantly associated with improved menstrual cycle regularity (RR 1.56; 95% CI 1.01 to 2.41; p = 0.04), and lower values of modified Ferriman-Gallwey score (MD -0.97; 95% CI -1.53 to -0.40; p < 0.01) and LH/FSH ratios (MD -0.13; 95% CI -0.24 to -0.03; p = 0.01). Differences in acne (p = 0.58), body mass index (p = 0.13), fasting blood glucose (p = 0.07) and HOMA-IR (p = 0.25) were not statistically significant.

Conclusion: In this meta-analysis of RCTs, combination therapy was associated with cycle regularization and reduction in hirsutism and LH/FSH ratio compared to metformin monotherapy. Further studies are needed to clarify the true benefits of the use of inositol in PCOS treatment.

Keywords: D-chiro-inositol; Metformin; Myoinositol; Polycystic ovary syndrome.