Prognostic factors for acute exacerbation of idiopathic pulmonary fibrosis: Protocol for a systematic review and meta-analysis

Introduction Idiopathic pulmonary fibrosis (IPF) is a form of chronic fibrosing interstitial pneumonia with unknown disease aetiology. Acute exacerbation (AE) of IPF is an accelerated disease progression beyond its expected course. A 30-day mortality of AE of IPF is 40%. While death may occur, there is much variation in the clinical progression of this condition. Previous attempts have been made to investigate various possible prognostic factors for AE of IPF; however, they have yet to be confirmed. The aim of this systematic review is to clarify these prognostic factors. Methods and analysis In this review, AE of IPF is the condition of interest, which has been defined according to previously established diagnostic criteria. The primary outcomes of interest include short-term all-cause mortality and pulmonary-cause mortality. The secondary outcomes of interest include long-term mortality and hospital separation for the disease. Primary studies investigating prognostic factors for AE of IPF are eligible for inclusion in this review. All study types are permitted except case reports. Two reviewers will search electronic databases, such as Medline and EMBASE, from 2002 to the 1 April 2019 and extract data independently. Risk of bias in individual studies will be assessed using the Quality in Prognostic Studies tool. Meta-analysis will be conducted for univariate data if at least three studies report the effect of a specific prognostic factor using similar statistical methods. Multivariate results will be reported qualitatively. Subgroup analysis and sensitivity analysis will be considered with the aim of generalising findings to the clinical settings and drawing more robust conclusions. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) method will be applied to evaluate the quality of evidence for each prognostic factor. Ethics and dissemination Ethical approval will not be required. Results will be reported in a peer-reviewed scientific journal.