Opioid receptor mu 1 (OPRM1) A118G polymorphism (rs1799971) and postoperative nausea and vomiting

OPRM1-A118G polymorphism (A > G, rs1799971) is associated with interindividual variability in both response to postoperative pain and opioid treatment. The aim of this meta-analysis is to identify the predictive strength in the current literature of OPRM1-A118G polymorphism to postoperative anesthetic reactions, including nausea, vomiting, pruritus and dizziness.

PubMed, EMBASE, Cochrane Library, Web of Knowledge, Google Scholar and CNKI database were searched to find gene-association researches exploring the impacts of OPRM1-A118G polymorphism on postoperative side effects (time: up to July 2016). Odd ratios (ORs) with 95% confidence intervals (95% CIs) were estimated in allele model, homozygote model, heterozygote model, dominant model and recessive model. Sensitivity analysis and potential bias were also assessed.

137 articles were retrieved from databases. 17 eligible studies, including 4690 patients were considered in the meta-analysis. The ORs with 95% CIs of postoperative nausea, vomiting, nausea and vomiting (PONV), pruritus and dizziness in the five genetic models mentioned above were determined. Postoperative vomiting was significantly associated with OPRM1-A118G polymorphism in homozygote (OR: 0.422; 95% CI: 0.254, 0.701; P = 0.001), dominant (OR: 0.765; 95% CI: 0.592, 0.987; P = 0.040) and recessive (OR: 0.439; 95% CI: 0.268, 0.717; P = 0.001) models. The 118G allele was associated with a reduced risk of vomiting. No other associations were detected. There was no evidence of publication bias.

OPRM1-A118G polymorphism (A > G) is associated with a reduced risk of postoperative vomiting, but not nausea, pruritus and dizziness. The results should be interpreted with caution due to limited sample and possible heterogeneity between the included studies. Well-designed and large-scale studies are necessary to confirm our results.