Abstract：
OBJECTIVE: L-carnitine supplementation has been recommended to improve cardiometabolic health markers in diabetic patients. Our purpose was to assess the dose-dependent effects of l-carnitine supplementation on cardiometabolic risk factors in patients with type 2 diabetes.
METHODS: PubMed/Medline, Scopus, and Web of Science were searched until May 2022 for randomized controlled trials that examined the impact of l-carnitine supplementation on cardiometabolic risk factors in adults with type 2 diabetes. The mean difference (MD) and its 95% confidence interval (CI) were estimated utilizing a random-effects model. Nonlinear dose-response associations were modeled with restricted cubic splines. The certainty of evidence was rated using the GRADE approach.
RESULTS: Twenty-one randomized trials with 2041 patients with type 2 diabetes were included. We found that every 1 g/d supplementation with l-carnitine significantly reduced body mass index (MD: -0.37 kg/m2, 95% CI: -0.59, -0.15; I2 =93%, n=13, GRADE=low), HbA1c (MD: -0.16%, 95% CI: -0.32, -0.01; I2 = 94%, n = 18, GRADE = moderate), and low-density lipoprotein cholesterol (MD: -0.11 mmol/L, 95% CI: -0.16, -0.05; I2 = 91%, n = 11, GRADE = high). There were also reductions in serum triglycerides (MD: 0.07 mmol/L), total cholesterol (MD: -0.13 mmol/L), and fasting plasma glucose (MD: -0.17 mmol/L). A U-shaped effect was demonstrated for body mass index, with the largest reduction at 2 g/d. A linear reduction was seen for serum triglycerides, total cholesterol, and fasting plasma glucose up to l-carnitine supplementation of 4 g/d.
CONCLUSIONS: L-carnitine supplementation resulted in a small reduction in serum lipids and plasma glucose in patients with type 2 diabetes. However, due to high statistical heterogeneity, the results should be interpreted very cautiously.
METHODS: PubMed/Medline, Scopus, and Web of Science were searched until May 2022 for randomized controlled trials that examined the impact of l-carnitine supplementation on cardiometabolic risk factors in adults with type 2 diabetes. The mean difference (MD) and its 95% confidence interval (CI) were estimated utilizing a random-effects model. Nonlinear dose-response associations were modeled with restricted cubic splines. The certainty of evidence was rated using the GRADE approach.
RESULTS: Twenty-one randomized trials with 2041 patients with type 2 diabetes were included. We found that every 1 g/d supplementation with l-carnitine significantly reduced body mass index (MD: -0.37 kg/m2, 95% CI: -0.59, -0.15; I2 =93%, n=13, GRADE=low), HbA1c (MD: -0.16%, 95% CI: -0.32, -0.01; I2 = 94%, n = 18, GRADE = moderate), and low-density lipoprotein cholesterol (MD: -0.11 mmol/L, 95% CI: -0.16, -0.05; I2 = 91%, n = 11, GRADE = high). There were also reductions in serum triglycerides (MD: 0.07 mmol/L), total cholesterol (MD: -0.13 mmol/L), and fasting plasma glucose (MD: -0.17 mmol/L). A U-shaped effect was demonstrated for body mass index, with the largest reduction at 2 g/d. A linear reduction was seen for serum triglycerides, total cholesterol, and fasting plasma glucose up to l-carnitine supplementation of 4 g/d.
CONCLUSIONS: L-carnitine supplementation resulted in a small reduction in serum lipids and plasma glucose in patients with type 2 diabetes. However, due to high statistical heterogeneity, the results should be interpreted very cautiously.
摘要：
目的：建议补充左旋肉碱以改善糖尿病患者的心脏代谢健康指标。我们的目的是评估补充左卡尼汀对2型糖尿病患者心脏代谢危险因素的剂量依赖性影响。
方法：PubMed/Medline，Scopus,和WebofScience在2022年5月之前搜索了随机对照试验，这些试验研究了补充左卡尼汀对2型糖尿病成人心脏代谢危险因素的影响。使用随机效应模型估计平均差（MD）及其95％置信区间（CI）。用有限的三次样条对非线性剂量反应关联进行建模。使用等级方法对证据的确定性进行评级。
结果：纳入21项随机试验，纳入2041例2型糖尿病患者。我们发现，每1g/d补充左旋肉碱可显着降低体重指数（MD：-0.37kg/m2，95％CI：-0.59，-0.15;I2=93％，n=13，等级=低），HbA1c（MD：-0.16%，95%CI：-0.32，-0.01；I2=94%，n=18，等级=中等），和低密度脂蛋白胆固醇（MD：-0.11mmol/L，95%CI：-0.16，-0.05；I2=91%，n=11，等级=高）。血清甘油三酯也有减少（MD：0.07mmol/L），总胆固醇（MD：-0.13mmol/L），和空腹血糖（MD：-0.17mmol/L）。身体质量指数呈U型效应,最大降幅为2g/d。血清甘油三酯呈线性下降，总胆固醇,和空腹血糖高达4g/d的左旋肉碱补充。
结论：补充L-肉碱可使2型糖尿病患者的血脂和血糖略有降低。然而,由于高度的统计异质性，结果应该非常谨慎地解释。
方法：PubMed/Medline，Scopus,和WebofScience在2022年5月之前搜索了随机对照试验，这些试验研究了补充左卡尼汀对2型糖尿病成人心脏代谢危险因素的影响。使用随机效应模型估计平均差（MD）及其95％置信区间（CI）。用有限的三次样条对非线性剂量反应关联进行建模。使用等级方法对证据的确定性进行评级。
结果：纳入21项随机试验，纳入2041例2型糖尿病患者。我们发现，每1g/d补充左旋肉碱可显着降低体重指数（MD：-0.37kg/m2，95％CI：-0.59，-0.15;I2=93％，n=13，等级=低），HbA1c（MD：-0.16%，95%CI：-0.32，-0.01；I2=94%，n=18，等级=中等），和低密度脂蛋白胆固醇（MD：-0.11mmol/L，95%CI：-0.16，-0.05；I2=91%，n=11，等级=高）。血清甘油三酯也有减少（MD：0.07mmol/L），总胆固醇（MD：-0.13mmol/L），和空腹血糖（MD：-0.17mmol/L）。身体质量指数呈U型效应,最大降幅为2g/d。血清甘油三酯呈线性下降，总胆固醇,和空腹血糖高达4g/d的左旋肉碱补充。
结论：补充L-肉碱可使2型糖尿病患者的血脂和血糖略有降低。然而,由于高度的统计异质性，结果应该非常谨慎地解释。
