L-carnitine treatment of insulin resistance: A systematic review and meta-analysis

Background. L-carnitine has been used for several years as an adjuvant therapy in oxidative stress, blood sugar, high-sensitivity C-reactive protein (CRP), anemia, etc. However, the efficacy of L-carnitine treating insulin resistance (IR) remains controversial. Homeostasis model assessment of Insulin Resistance (HOMA-IR) is widely used in the clinical evaluation of patients with IR. Objectives. A meta-analysis, including randomized controlled trials (RCTs), was performed to assess the effect of L-carnitine on HOMA-IR patients. Material and methods. The Cochrane Library, PubMed, and EMBASE databases were systematically searched to identify RCTs which evaluated the effects of L-carnitine on HOMA-IR patients. We screened relevant studies according to predefined inclusion and exclusion criteria. In the selected articles, we extracted the data: study design, sample size, age, L-carnitine dose and regimen, body mass index (BMI) of patients, mode of administration, study duration and study outcomes. Results. A total of 5 studies were included for the meta-analysis. The result showed L-carnitine was useful in the treatment of IR (WMD -0.724, CI -0.959 -0.488, p < 0.0001). Evaluation at 3, 6, 9, 12 months, the p-values were 0.875, 0.165, 0.031, 0, 007, respectively. Conclusions. L-carnitine was useful in treating patients with IR. L-carnitine can treat IR more effectively with prolonging the medication time. However, more RCTs with long-term L-carnitine treatment of IR are needed to confirm the viewpoint.