# Epidemiology of idiopathic pulmonary fibrosis: a population registry-based study

## TL;DR

This study analyzed IPF in Tuscany, finding higher rates in men and older adults, with poor long-term survival.

## Contribution

The study provides updated population-based estimates of IPF prevalence, incidence, and survival in Tuscany.

## Key findings

- IPF prevalence was 21.5 per 100,000, higher in men and the 70–79 age group.
- Survival rates were 91.3%, 51.4%, and 22.2% at 1, 5, and 10 years, respectively.
- Men had a 52% higher mortality risk than women, and older age worsened survival.

## Abstract

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive respiratory rare disease characterized by an irreversible loss of lung function, with unknown etiology and poor prognosis.

A population registry-based study was conducted to provide estimates of prevalence, incidence and survival of IPF. The study included all cases diagnosed with IPF in the years 2000–2022 and residing in Tuscany, Italy. Prevalence as of December 31, 2022, was calculated by sex and age class. Incidence was calculated across the period 2018–2022. Survival at 1, 5 and 10 years from diagnosis with 95% confidence intervals (CI) was estimated by sex and age class using the Kaplan-Meyer method. The independent effect of sex and age at diagnosis on survival was estimated by Cox proportional hazard model.

A total of 1,388 subjects with IPF were diagnosed during the study period. The prevalence as of 31st December 2022 was 21.5 cases (95%CI: 20.0–23.0) per 100,000 inhabitants, with a significantly higher frequency in men and in 70–79 years age group (p < 0.0001). The average annual incidence was 4.6 cases per 100,000 inhabitants, with significantly higher incident cases among males (p < 0.0001). Survival at 1, 5 and 10 years from diagnosis was 91.3%, 51.4% and 22.2%, respectively. Women exhibited a longer survival than men (34.8% vs. 17.3% at 10 years), while patients under 70 had the highest survival rate at 58.2% (95% CI: 52.5–63.4) at five years. Cox regression model confirmed a higher risk of mortality for men (adjusted Hazard Ratio – adjHR = 1.52, 95%CI: 1.25–1.84, p < 0.0001) and with age at diagnosis (adjHR = 1.04, 95%CI: 1.03–1.05, p < 0.0001).

The higher prevalence and incidence rates of IPF among men, as indicated by this population registry-based study, align with recent data reported in Europe. Furthermore, IPF is consistently identified as a disease with a poor prognosis, especially in male patients. Therefore, early and accurate diagnosis, coupled with timely management, is essential to improve the care and treatment outcomes for these patients.