Interstitial lung diseases among patients hospitalized in the Department of Respiratory Medicine in Radom District Hospital during the years 2000-2009.

Introduction: There is little epidemiological data on interstitial lung diseases (ILDs) in Poland. The aim of the present study was to estimate the frequency of ILDs and frequency of the respiratory failure and the hospital mortality due to ILDs during the period 2000-2009 in Radom District Hospital. Methods: Cases were identified through database of 20481 patients hospitalized in the Department of Respiratory Medicine in Radom District Hospital. The study encompassed the period from January 1, 2000 to December 31, 2009. According to national census data the total population of Radom region (former Radom Voivodeship) is about 630,000 adult (〉 14 years) inhabitants. The population is mixed urban/rural and remained stable during the period 2000-2009. Diagnosis of ILD was based on: clinical data, laboratory examination, high resolution lung CT scan (HRCT), lung function tests and in some patients - the results of open or transbronchial lung biopsies. ILDs were recorded in the hospital database according to ICD-10 criteria. Results: Between 2000 and 2009 a total of 554 patients were diagnosed with ILDs, in the course of 708 hospitalizations. The mean number of hospitalizations per patient was 1.3 (range 1-11). Admissions due to ILDs encompassed 3.5% of the total hospital admissions. A 20% increase in the annual rate of hospitalizations due to ILDs (from 10.7/100,000 between 2000- -2004 to 12.8/100,000 between 2005-2009) was recorded. Most frequent ILD diagnosis was interstitial pneumonia and fibrosis (J84) - 55.7% (including idiopathic pulmonary fibrosis [IPF] - J84.1-27.5%) and sarcoidosis (D86) - 25%. During the study period the increase in hospitalizations was observed in patients with sarcoidosis (+55%) and in the group of interstitial pneumonia and fibrosis (+39%), but the decrease (-38%) in the group of pneumoconiosis (J60-J68). Sex ratio (M/F) was 1.5/1 for all ILDs; ranging from 1.2/1 for D86 and J84 to 4.7/1 for radiotherapy and drug induced ILDs (J70) and 7.1/1 for J60-J68. Respiratory failure was found in over 50% of patients with IPF and pneumoconiosis but only occasionally in the course of sarcoidosis (7%). 6.3% of all ILDs patients died within 10 years, the mortality was the highest in interstitial pneumonia and fibrosis (4.3% of all ILDs patients died due to J84) and the lowest in sarcoidosis (only 1 patient - 0.18% died due to D86). Crude incidence rates were estimated to be 8.8/100,000 adults (〉 14 years) for all ILDs; 5/100,000 for J84 (2.5/100 000 for J84.1, 0.3/100,000 for COP - cryptogenic organizing pneumonia and rare ILD's); 2.3/100,000 for D86, 1/100,000 for J60- -J68, 0.2/100,000 for J70 and 0.3/100,000 for collagen tissue disease associated ILDs (J99). Ten years prevalence rates per 100,000 adults were: 87.7 for all ILDs; 50 for J84 (25.5 for J84.1; 3 for COP and rare ILDs); 23.1 for D86; 9.8 for J60-J68; 2.1 for J70 and 2.7 for J99. Conclusions: The incidence rates of ILDs found in our study are lower than that reported in recent European studies. Our study was based on data of single hospital center for respiratory medicine and probably underestimate the real incidence rates of ILDs. On the other hand, 10 years prevalence estimates are concordant with available epidemiological data. Comparisons of the relative frequencies are probably accurate and idiopathic pulmonary fibrosis and sarcoidosis appear to be the most frequent ILDs.