Clinical outcomes of laryngopharyngeal reflux treatment: A systematic review and meta-analysis

Objectives: To investigate the therapeutic benefit of proton pump inhibitors (PPIs) over placebo in patients with laryngopharyngeal reflux (LPR) and to analyze the epidemiological factors of heterogeneity in the literature. Methods: An electronic literature search was conducted to identify articles published between 1990 and 2018 about clinical trials describing the efficiency of medical treatment(s) on LPR. First, a meta-analysis of placebo randomized controlled trials (RCTs) comparing PPIs versus placebo was conducted according to diet. The heterogeneity, response to PPIs, and evolution of clinical scores were analyzed for aggregate results. Second, a systematic review of diagnosis methods, clinical outcome of treatment, and therapeutic regimens was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Results: The search identified 1,140 relevant publications, of which 72 studies met the inclusion criteria for a total of 5,781 patients. Ten RCTs were included in the meta-analysis. The combined relative risk was 1.31 in favor of PPIs and increased to 1.42 when patients did not receive diet recommendations. Randomized controlled trials were characterized by a significant heterogeneity due to discrepancies in clinical therapeutic outcomes, diagnosis methods (lack of gold standard diagnostic tools), and therapeutic scheme. The epidemiological analysis of all articles supports the existence of these discrepancies in the entire literature. In particular, many symptoms and signs commonly encountered in LPR are not assessed in the treatment effectiveness. The lack of diagnosis precision and variability of inclusion criteria particularly create bias in all reported and included articles. Conclusion: This meta-analysis supports a mild superiority of PPIs over placebo and the importance of diet as additional treatment but demonstrates the heterogeneity between studies, limiting the elaboration of clear conclusions. International recommendations are proposed for the development of future trials.