Incidence and Prevalence of Idiopathic Pulmonary Fibrosis (IPF): A Systematic Literature Review and Meta-Analysis

OBJECTIVES: To summarize the published literature on the incidence and prevalence of IPF among adults within different regions.

METHODS: Comprehensive searches of MEDLINE®, Embase, and the Cochrane Database of Systematic Reviews were conducted for studies published in English from 2000-01-01 to 2023-11-07 reporting incidence or prevalence of IPF. Pooled weighted-mean incidence and prevalence estimates were calculated from studies reporting sufficient epidemiological data using a DerSimonian and Laird random-effects model.

RESULTS: Of 4,075 records, 31 studies were included for meta-analysis (20 reported both prevalence and incidence, 3 reported prevalence only, 8 reported incidence only). Most studies were retrospective; study periods ranged from 1984–2021. Pooled global incidence across 28 studies was 16.6 per 100,000 persons (95% confidence interval [95%CI]=12.3–20.9; median=6.6). Pooled incidence was 12.8 per 100,000 (95%CI=9.7–15.9; median=3.7) across six Asia-Pacific studies, 5.1 (95%CI=3.9–6.3; median=4.6) across thirteen studies in Europe and 34.8 (95%CI=7.1–62.6; median=9.0) across nine studies in North America. Pooled global prevalence across 23 studies was 51.7 per 100,000 (95%CI=24.5–78.8; median=16.6). Pooled prevalence was 14.8 per 100,000 (95%CI=7.1–22.6; median=12.0) across six Asia-Pacific studies, 14.6 (95%CI=9.4–19.7; median=12.6) across nine studies in Europe, and 120.8 (95%CI=1.7–240.0; median=24.0) across eight studies in North America.

CONCLUSIONS: This analysis found high incidence and prevalence of IPF in North America versus other regions. Findings may be explained by selective source populations in US studies (e.g., Medicare, Veteran database) versus general populations in European or Asian studies. US database studies also identified IPF cases using non-validated algorithms that combined different criteria and ICD codes, leading to over-estimated IPF cases. There is an urgent need to standardize and validate the diagnostic process of IPF in clinical practice. This will strengthen clinical trials assessing new drugs’ effectiveness and facilitate improved validity when comparing incidence and prevalence across regions and over time.