ABSTRACT
Abstract Objective: Salivary pepsin has emerged as a biomarker for Laryngopharyngeal Reflux (LPR), which, however, has been questioned for its efficacy due to a lack of supporting medical data. Therefore, this study analyzed the diagnostic value of salivary pepsin for LPR and assessed a better cutoff value. Methods: Studies were searched in PubMed, Embase, and Cochrane Library from their receptions to October 1, 2021. Then, RevMan 5.3 and Stata 14.0 were utilized to summarize the diagnostic indexes for further meta-analysis. Data were separately extracted by two reviewers according to the trial data extraction form of the Cochrane Handbook. The risk of bias in Randomized Control Trials (RCTs) was evaluated with the Cochrane Risk of Bias Tool. Results: A total of 16 studies matched the criteria and were subjected to meta-analysis. The results revealed a pooled sensitivity of 61% (95% CI 50%-71%), a pooled specificity of 67% (95% CI 48%-81%), a positive likelihood ratio of 2 (95% CI 1.2-2.8), a negative likelihood ratio of 0.58 (95% CI 0.47-0.72), and the area under the receiver operating characteristic curve of 0.67 (95% CI 0.63-0.71). Subgroup analyses indicated that the cutoff value of pepsin at 50 ng/mL had a higher degree of diagnostic accuracy than that of pepsin at 16 ng/mL in cohort studies. Conclusion: The review demonstrated low diagnostic performance of salivary pepsin for LPR and that the cutoff value of 50 ng/mL pepsin had superior diagnostic accuracy. Nevertheless, the diagnostic value may vary dependent on the utilized diagnostic criteria. Therefore, additional research is needed on the improved way of identifying salivary pepsin in the diagnosis of LPR, and also longer-term and more rigorous RCTs are warranted to further assess the effectiveness of salivary pepsin.