Idiopathic Pulmonary Fibrosis in a Referral Center in Iran: Are Patients Developing the Disease at a Younger Age?

Background: The incidence of idiopathic pulmonary fibrosis (IPF) appears to be increasing. In the western literature, the average age of presentation is in the seventh decade of life while it has been reported to be earlier in the Middle East and India. Given that a paucity of epidemiological data exists in Iran, we sought to describe the clinical pattern and course of the disease at a large Iranian referral center. Methods: A retrospective review was conducted of 132 patients diagnosed with IPF at the National Research Institute of Tuberculosis and Lung Diseases (NRITLD) in Tehran, Iran from 1988 through 2008. Data were collected from the medical records which consisted of demographics, clinical history, laboratory tests, pulmonary function tests (PFT), radiographic and pathology findings, treatment, and outcomes of the disease.Results: The mean age at diagnosis was 56.6 years (95% CI: 53.8 - 59.4) with no significant sex predilection. Common presenting symptoms included dyspnea and cough, which occurred for a mean period of 21 months prior to diagnosis. Common signs included end-inspiratory crackles and digital clubbing, which were found in 85.6% and 55.3% of the patients, respectively. Radiographically, reticular and reticulonodular opacities were seen in 47.3% and 20.9% of the patients, respectively on high resolution computed tomography (HRCT). In patients who underwent lung biopsy, diffuse interstitial fibrosis was seen in 91.1%. The mean follow-up time for all patients was 32.8 months (95% CI: 23.2 - 42.4, range: 1 - 257 months). There were 16 patients who died during the study period. The mean age of death was 56.8 years (95% CI: 46.2 - 67.4), which is significantly lower than the life expectancy in Iran (P-value: 0.017). The mean survival time for patients who died was 1.1 years (95% CI: 0.5 - 1.7) after diagnosis. The one- and three- year overall survival rates for all patients were 88% and 79%, respectively. Conclusion: The clinical characteristics of IPF in Iran are similar to those in the western literature. However, Iranian patients appear to be developing the disease a decade earlier than western patients.