Insulin resistance, fertility outcomes favour carnitine in PCOS
Carnitine appears to be beneficial in the treatment of women with polycystic ovary syndrome (PCOS), with the drug helping improve ovulation, clinical pregnancy, insulin resistance, and body mass index (BMI), according to the results of a meta-analysis.
Researchers conducted a systematic review of literature about the effect of carnitine on glucose and lipid metabolic profiles and fertility outcomes in women with PCOS. Multiple online databases were searched for relevant studies.
Seven studies met the eligibility criteria and were included in the meta-analysis. The total number of participants was 839. All participants had PCOS diagnosed by Rotterdam or Androgen Excess Society (AES) criteria and were taking carnitine supplement. The dosage of carnitine and treatment duration varied across studies, ranging from 250 to 3,000 mg daily and from 84 to 90 days, respectively. There was no publication bias detected.
Outcomes examined included fertility (ovulation, clinical pregnancy, live birth, and miscarriage), lipid parameters (BMI, triglyceride, total cholesterol, high-density lipoprotein, and low-density lipoprotein), fasting glucose and insulin, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR).
Pooled data showed that compared with placebo, carnitine resulted in significant improvements in ovulation rates (relative risk [RR], 3.42, 95 percent confidence interval [CI], 2.39–4.89, I2=0 percent) and pregnancy rates (RR, 11.05, 95 percent CI, 1.21–100.58, I2=79 percent). Live birth was not reported in any of the included studies.
After treatment, carnitine was also associated with significant reductions from baseline in BMI (mean difference [MD], −0.93 kg/m2, 95 percent confidence interval [CI] −1.15 to −0.70, I2=55.0 percent), insulin levels (MD, −2.47 mIU/L, 95 percent CI, −4.49 to −0.45, I2=0 percent), and the HOMA-IR (MD, −0.67, 95 percent CI, −1.20 to −0.14, I2=0 percent). However, these improvements were not observed for lipid profiles including triglyceride, total cholesterol, and low-density lipoprotein.
The analysis was limited by insufficient statistical power and the presence of potential confounder. Therefore, more studies are needed to validate the effects of carnitine of PCOS.