Orphanet Journal of Rare Diseases | Epidemiological Study of Idiopathic Pulmonary Fibrosis in Tuscany

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Based on 23 years of real-world data, this study provides the first comprehensive epidemiological profile of idiopathic pulmonary fibrosis (IPF) in Europe, revealing significant impacts of gender and age on survival outcomes, offering crucial evidence for early intervention in rare respiratory diseases.

 

Literature Overview

The article 'Epidemiology of idiopathic pulmonary fibrosis: a population registry-based study,' published in the Orphanet Journal of Rare Diseases, reviews and summarizes the prevalence, incidence, and survival rates of idiopathic pulmonary fibrosis (IPF) in the Tuscany region of Italy between 2000 and 2022. Leveraging a rare disease registry covering 3.6 million people, the study delivers long-term, population-based epidemiological data, highlighting higher IPF occurrence in males and the elderly, along with poor prognosis. It emphasizes the critical role of early diagnosis and timely intervention in improving patient outcomes.

Background Knowledge

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and typically fatal interstitial pneumonia of unknown cause, primarily affecting males over 60. It is characterized by irreversible decline in lung function due to pulmonary fibrosis. Despite approved antifibrotic drugs such as pirfenidone and nintedanib, the overall prognosis remains poor, with a median survival of approximately 3–5 years. IPF pathogenesis is thought to involve interactions between genetic susceptibility and environmental exposures (e.g., smoking, occupational dust), with core pathological processes including cellular senescence, telomere dysfunction, and alveolar epithelial injury. Diagnosis currently relies on high-resolution CT and multidisciplinary discussion, but early symptoms such as dry cough and dyspnea are often overlooked, leading to delayed diagnosis. Epidemiological studies are mostly based on single-center or administrative databases, introducing selection bias. This study uses a region-wide rare disease registry, covering long-term population data, filling a critical gap in Europe by simultaneously evaluating the three core epidemiological indicators of IPF—prevalence, incidence, and survival—thus holding significant public health relevance.

 

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Methods and Experiments

This population-based retrospective cohort study included patients diagnosed with IPF between 2000 and 2022 in the Tuscany region. Data were extracted from the Regional Rare Disease Registry (RRDR), where specialized centers designated by the regional rare disease network report cases, ensuring diagnostic accuracy. The study calculated the prevalence (per 100,000 residents) as of December 31, 2022, the average annual incidence from 2018 to 2022, and used the Kaplan-Meier method to estimate 1-, 5-, and 10-year survival rates. A Cox proportional hazards model assessed the independent effects of gender and age at diagnosis on survival, with results expressed as adjusted hazard ratios (adjHR) and 95% confidence intervals. Statistical analyses were performed using Stata 16, with p < 0.05 considered statistically significant.

Key Findings and Insights

• From 2000 to 2022, 1,388 IPF cases were identified, with a male-to-female ratio of 3.0:1, indicating significantly more male patients
• As of December 31, 2022, the IPF prevalence was 21.5 per 100,000, with 31.9 per 100,000 in males and 11.6 per 100,000 in females, a significant difference (p < 0.0001)
• The average annual incidence from 2018 to 2022 was 4.6 per 100,000, with 9.0 per 100,000 in males and 2.3 per 100,000 in females, showing significantly higher incidence in males
• IPF prevalence was highest in the 70–79 age group (99.6 per 100,000), followed by ≥80 years (41.3 per 100,000) and <70 years (8.4 per 100,000)
• Overall 1-, 5-, and 10-year survival rates were 91.3%, 51.4%, and 22.2%, respectively, with females showing significantly higher 10-year survival (34.8%) than males (17.3%)
• Five-year survival was highest in patients diagnosed <70 years (58.2%) and lowest in those ≥80 years (36.1%)
• Cox regression analysis showed that male sex increased the risk of death by 52% after IPF diagnosis (adjHR=1.52), and each additional year of age at diagnosis increased the mortality risk by 4% (adjHR=1.04)

Implications and Future Directions

This study provides the first long-term, population-based epidemiological data on IPF in Europe, confirming its high incidence and mortality in males and the elderly. The results highlight the independent prognostic value of gender and age in IPF, suggesting a need for enhanced screening and monitoring of high-risk populations.

Although the lack of clinical data such as treatment and lung function is a limitation, the large sample size and long follow-up enhance the reliability of the findings. Future studies could integrate biomarkers and radiomics to refine risk stratification models. Additionally, this study supports the continued use of population registries for rare disease surveillance in real-world settings, providing high-quality evidence for health policy and drug development.

 

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Conclusion

Basing on 23 years of real-world data from Tuscany, this study systematically reveals the epidemiological characteristics of idiopathic pulmonary fibrosis (IPF). The results show an IPF prevalence of 21.5 per 100,000 and an annual incidence of 4.6 per 100,000, both significantly higher in males and individuals aged 70 or older. Survival analysis indicates poor prognosis, with only 22.2% of IPF patients surviving 10 years, and even lower survival rates among males and older patients. Cox regression confirms that male sex and older age at diagnosis are independent risk factors for mortality. This study provides vital data on the public health burden of IPF in Europe, underscoring the necessity of early identification of high-risk individuals and timely intervention. The population-based registry design enhances the representativeness and generalizability of the findings, offering a methodological model for future epidemiological studies of rare respiratory diseases. Despite the absence of detailed clinical variables, this study delivers a robust evidence base for clinical practice and policy-making.

 

Gorini Francesca, Santoro Michele, Pierini Anna, Bargagli Elena, and Coi Alessio. Epidemiology of idiopathic pulmonary fibrosis: a population registry-based study. Orphanet Journal of Rare Diseases.