Efficacy of pirfenidone in fibrotic hypersensitivity pneumonitis: a systematic review and meta-analysis of randomized controlled trials

Background: Fibrotic hypersensitivity pneumonitis (HP), a progressive and irreversible interstitial lung disease (ILD), carries a significant risk of morbidity and mortality due to the narrow range of therapeutic options available. The role of anti-fibrotic drugs for this disease entity has been called into question, and the results of various studies have been unclear so far. This meta-analysis evaluates the efficacy of the drug pirfenidone, an anti-fibrotic agent in fibrotic HP, to document a clear consensus of the benefits in disease outcomes. Materials and methods: PubMed, Scopus, and MEDLINE were searched for the randomized controlled trials (RCTs) evaluating the efficacy of pirfenidone in fibrotic HP against a placebo. Data were extracted from the RCTs that met the inclusion criteria, and pooled analysis was performed to evaluate the significance of % Predicted FVC (forced vital capacity), % Predicted DLCO (diffusion capacity of carbon monoxide), and change in SGRQ (George’s respiratory questionnaire) at the completion of the trial. Results: No significant change was observed in the % predicted FVC [Mean difference (MD): 3.65; 95% Confidence interval (CI): −1.63, 8.94; P : 0.18] and the % predicted DLCO [MD: 7.64; 95% CI: −1.46, 16.74; P : 0.10]. However, there was a significant decrease in the SGRQ score at the end of the intervention [MD: −5; 95% CI: −6.88, −3.12; P < 0.00001]. Conclusion: Pirfenidone was not associated with a significant change in the lung function metrics, but it has been shown to improve the quality of life, as evidenced by a significant decrease in the SGRQ score.