Mortality-related risk factors of idiopathic pulmonary fibrosis: a systematic review and meta-analysis.

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) has high mortality and poor prognosis, which brings enormous burdens to families and society. We conducted this meta-analysis to analyze and summarize the risk factors associated with mortality in IPF, hoping to provide reference for clinical prevention and treatment of IPF.

METHODS

We conducted a comprehensive search of PubMed, Cochrane Library, Embase, and Web of Science from inception to August 10, 2023, to include cohort studies on mortality in patients with IPF. Two researchers independently screened the studies and extracted data. The Newcastle-Ottawa Scale (NOS) was used to assess the methodological quality of studies. Hazard ratios (HRs) and 95% confidence intervals (CIs) were reported to identify risk factors for mortality in IPF. In addition, we also carried out sensitivity analysis, Begg's and Egger's tests to evaluate the heterogeneity and publication bias.

RESULTS

Eighteen studies comprising 8,408 patients were included. The meta-analysis suggested that age (HR =1.03; 95% CI: 1.01, 1.04; P<0.001), forced vital capacity (FVC) (HR =0.97; 95% CI: 0.96, 0.99; P=0.005), FVC to predicted value ratio (FVC% pred) (HR =0.98; 95% CI: 0.97, 0.99; P0.001), diffusing capacity of the lungs for carbon monoxide to predicted value ratio (DL% pred) (HR =0.98; 95% CI: 0.97, 0.99; P<0.001), gender-age-physiology (GAP) index (HR =1.70; 95% CI: 1.20, 2.40; P=0.003), and lung cancer (HR =2.75, 95% CI: 1.23, 6.15; P=0.01) were mortality-related risk factors in patients with IPF. Whereas, gender, smoking, body mass index (BMI), diffusing capacity of the lungs for carbon monoxide (DL), C-reactive protein (CRP), 6-minute walking distance (6MWD), pulmonary hypertension, gastroesophageal reflux, and cardiovascular disease were not statistically associated with death.

CONCLUSIONS

Age, FVC, FVC% pred, DL% pred, GAP index, and lung cancer have been identified as potential risk factors for mortality in patients with IPF. Due to the limited number and quality of included studies, the conclusions need to be verified by further studies.