Effect of anti-reflux therapy on pulmonary function in idiopathic pulmonary fibrosis: a systematic review and meta-analysis

BACKGROUND: Current guideline conditionally recommends regular use of anti-reflux medication in idiopathic pulmonary fibrosis (IPF). However, the effect of anti-reflux therapy in this group remains controversial. We systematically reviewed literatures to evaluate whether anti-reflux therapy could ameliorate pulmonary function in IPF. METHODS: We performed electronic search in PubMed, Embase and CENTRAL (Cochrane Central Register of Controlled Trials) to identify original articles published in English language. We included randomized controlled trials (RCTs) and observational studies regarding anti-reflux therapy on pulmonary function in IPF. Qualitative and quantitative analyses were conducted. In quantitative analysis, the inverse-variance method with fixed-effect model was used to analyze pooled data. RESULTS: Fifteen studies (2 RCTs and 13 observational studies) including 3,891 patients with IPF were included. Pooled analysis suggested that anti-reflux therapy did not improve forced vital capacity (FVC)% predicted [mean difference (MD) =0.88, 95% confidence interval (CI): −0.22 to 1.98, P=0.12, I(2) =0%, 8 studies, n=3,076], diffusing capacity of the lung for carbon monoxide (DLCO) % predicted (MD =0.75, 95% CI: −0.13 to 1.62, P=0.10, I(2) =0%, 8 studies, n=3,073), and FVC decline (MD =0.02, 95% CI: −0.01 to 0.04, P=0.29, I(2) =17%, 5 studies, n=1,586) in IPF. DISCUSSION: Anti-reflux therapy may not ameliorate pulmonary function in IPF. However, adequately powered studies are warranted to validate the present findings.