Impact of Interstitial Lung Disease on Mortality in ANCA-associated Vasculitis: A Systematic Literature Review and Meta-analysis

Abstract Background: Several retrospective series and case reports have described the association of interstitial lung disease (ILD) and ANCA-associated vasculitis（AAV）. However, the relationship between the ILD and mortality in AAV patients have not been established so far. This study aims to estimate the relevance of AAV-associated-ILD（AAV-ILD）and mortality risk by conducting a systematic review and meta-analysis.Methods: A comprehensive systematic review was conducted in accordance with the guidelines of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses). PubMed, Embase.com and the Cochrane Library (Wiley) were searched for original observational studies. Summary estimates were derived with a random-effects model and reported as risk ratio（RR）, tested for publication bias and heterogeneity. Results: Ten retrospective cohort studies were included, comprising 526 AAV-ILD patients enrolled from 1974 to 2018. Meta-analysis yielded a pooled RR of 2.90 (95% confidence interval 1.77 to 4.74) for death among those with AAV-ILD compared with control group. Sensitivity analysis suggested that the meta-RR result was not skewed by a single dominant study.Conclusion: ILD might be associated with a higher mortality risk in AAV patients.