More studies needed to assess effects of inositol on PCOS outcomes
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Key takeaways:
- Randomized controlled trials found varying metabolic outcomes for women with PCOS receiving different types of inositol.
- Providers should use shared decision-making when considering inositol for women with PCOS.
Findings on the use of inositol for managing polycystic ovary syndrome are inconclusive, with results varying based on therapy, trial design and outcomes reported, according to a systematic review and meta-analysis.
In an article published in The Journal of Clinical Endocrinology & Metabolism, researchers conducted a systematic review and meta-analysis on the efficacy of inositol for managing PCOS to inform the 2023 International Evidence-based Guideline for the Assessment and Management of PCOS. In the meta-analysis, researchers graded most of the available evidence as low to very low in certainty and said the metabolic outcomes varied in part based on the type of inositol used in the study.
“D-chiro inositol may improve some, but not all, metabolic outcomes while placebo was superior to D-chiro inositol for BMI,” Carolyn Ee, PhD, MBBS, FRACGP, MMed, associate professor at the NICM Health Research Institute at Western Sydney University in Australia, told Healio. “For most outcomes, there was no difference between metformin and myo-inositol or folic acid alone and myo-inositol plus folic acid, though metformin may be superior for waist-to-hip ratio and hirsutism, and myo-inositol plus folic acid was superior to folic acid alone for some, but not all, metabolic outcomes.”
Ee and colleagues conducted a systematic review and meta-analysis of randomized controlled trials assessing the use of myo-inositol alone, D-chiro inositol alone or either agent combined with usual care, lifestyle intervention or any other intervention for the management of PCOS among women. All trials included a control group receiving placebo, usual care alone, lifestyle intervention alone or any other intervention. MEDLINE, PsycINFO, Embase, Evidence-Based Medicine (EBM) and CINAHL databases were searched from inception until Aug. 5, 2022. Trials reporting on hormonal, metabolic, lipid, psychological, anthropometric and reproductive outcomes as well as adverse events were included.
D-chiro inositol may lower glucose
There were 30 trials included in the meta-analysis. Researchers conducted meta-analyses on three types of trials: D-chiro inositol alone vs. placebo, myo-inositol plus folic acid vs. folic acid, and myo-inositol alone vs. metformin.
In two trials comparing either 600 mg or 1,200 mg D-chiro inositol with placebo, women receiving D-chiro inositol had lower area under the curve insulin (mean difference, –3.65 µU/L/min), lower AUC glucose (mean difference, –20.85 µU/L/min) and lower triglycerides (mean difference, –31.95 mg/dL) than the placebo group. Women receiving D-chiro inositol had a higher BMI than those receiving placebo (mean difference, 0.67 kg/m2). Those in the D-chiro inositol group were more likely to have an ovulation event than the placebo group (OR = 11.5).
Few benefits with myo-inositol
Eight studies compared myo-inositol plus folic acid with folic acid. In those studies, 432 women received myo-inositol plus folic acid and 457 received folic acid alone. Women receiving myo-inositol plus folic acid had a lower fasting insulin (mean difference, –4.17 µU/mL) and lower homeostasis model assessment for insulin resistance (mean difference, –1.24) than women receiving folic acid alone. No other differences were observed.
Ten trials compared myo-inositol with metformin. Within the trials, 353 women received myo-inositol and 356 received metformin. In two trials, women receiving myo-inositol had a higher Ferriman-Gallwey score indicating worse hirsutism than those receiving metformin (mean difference, 2.42 points). Myo-inositol was associated with higher sex hormone-binding globulin than metformin (mean difference, 3.85 nmol/L). Metformin was associated with a lower waist-to-hip ratio than myo-inositol. No differences were observed for other outcomes.
Among six trials assessing adverse events, women receiving myo-inositol were less likely to have gastrointestinal adverse events than those receiving metformin (OR = 0.09; 95% CI, 0.02-0.37).
Shared decision-making needed
Ee said the majority of the findings in the meta-analyses were of low certainty and that further randomized controlled trials are needed. In the meantime, Ee recommended that providers use a patient-centered approach and engage in shared decision-making when considering inositol use.
“Clinicians can assist their patients to weigh the potential benefits and risks of using inositol,” Ee said. “It’s important to note that the risks of using inositol include financial risk and varying levels of regulation. Inositol has fewer adverse events compared to metformin; however, these are generally mild and self-limiting in the case of metformin. It would be reasonable to consider inositol for management of body weight and metabolic outcomes if metformin is not tolerated; however, it’s unclear if there is a benefit from adding inositol to metformin.”
Reference:
International evidence-based guideline for the assessment and management of polycystic ovary syndrome. Available at: https://www.monash.edu/medicine/mchri/pcos/guideline. Published February 2023. Accessed Feb. 19, 2024.
For more information:
Carolyn Ee, PhD, MBBS, FRACGP, MMed, can be reached at c.ee@westernsydney.edu.au.
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