Abstract
Objective Idiopathic inflammatory myopathy-associated interstitial lung disease (IIMILD) can range from rapidly-progressive with high mortality to indolent with minimal morbidity. This systematic review and meta-analysis describes immunological, clinical and radiographical predictors of mortality in IIM-ILD.
Methods MEDLINE and EMBASE database searches were completed on 18/10/21 for articles providing survival data according to baseline characteristics in patients with concurrent IIM and ILD. Prognostic factors common to >5 papers were included in meta-analysis using a random-effects model to report odds ratio for binary variables and hedge's g for continuous variables. Risk of bias was assessed by Newcastle- Ottawa score and Egger's test for publication bias.
Results From 4433 articles, 62 papers were suitable for inclusion, considering 38 different variables. OR for risk of death for anti-MDA-5 was 6.20 (3.58-10.71), and antitRNA- synthetase was protective OR=0.24 (0.14-0.41). ANA, Anti-Ro52 or SS-A did not significantly alter mortality, nor was MDA-5 titre predictive. Age, male gender, acute/sub-acute onset, clinically amyopathic disease, dyspnoea, ulceration, fever, raised CRP, ferritin, LDH, A-aO2 gradient, ground-glass opacities on HRCT and overall HRCT score; and reduced albumin, lymphocytes, PF ratio, %TLCO and %VC are all examples of prognostic factors significantly associated with mortality in this study. Baseline SP-D and KL-6 were not predictors of mortality.
Conclusion Many mortality risk factors were identified, though heterogeneity was high with low quality of evidence and risk of publication bias. Anti-MDA5 disease, and studies from East Asia predominate and may mask risk factors relevant to other IIM subgroups or populations.
