Incidence and prevalence of progressive pulmonary fibrosis (PPF): A systematic literature review and meta-analysis

BACKGROUND: Progressive pulmonary fibrosis (PPF) has only recently been defined. This study aimed to estimate the global incidence and prevalence of PPF and assess regional variations. METHODS: MEDLINE®, Embase, and Cochrane Database of Systematic Reviews were searched from 01/01/2000 to 11/07/2023 for English-language studies reporting incidence or prevalence of PPF. A DerSimonian-and-Laird random-effects model was used to calculate pooled weighted-mean incidence/prevalence estimates. RESULTS: Of 3823 abstracts, five studies were included for meta-analysis. Pooled global incidence across four studies was 10.9/100,000 (95% confidence interval: 1.3-20.5). In Europe, pooled incidence across two studies was 6.7/100,000 (2.2-11.3). Reported incidence rates were 2.4/100,000 in South Korea and 27.6/100,000 in the United States (US). Pooled global prevalence across all studies was 37.0/100,000 (23.6-50.5). Within Europe, pooled prevalence from two studies was 30.2/100,000 (0.0-61.9); prevalence estimates were 6.4 in South Korea, and 57.8 and 60.7 in two US studies. CONCLUSIONS: PPF appears rare globally, with higher incidence and prevalence in the US. Standardized definitions are needed for more accurate estimates.