Association between ischaemic heart disease and interstitial lung disease: a case-control study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is increasing in incidence. One of the authors noted that many of his patients with IPF were taking statins, and suspected an association. A case-control study was undertaken to investigate the association of statins with interstitial lung disease.

METHODS: The study population comprised patients attending the respiratory outpatients diagnosed with IPF between the beginning of 1999 and the beginning of July 2004, and 50 cases were identified. Data regarding the age, sex, smoking habits, occupational histories, exposure to birds, co-morbidity (ischaemic heart disease, diabetes, atrial fibrillation, and hyperlipidaemia), biopsy evidence for IPF, and use of beta blockers, statins, aspirin, NSAIDS, loop diuretics and proton pump inhibitors were recorded. Two age and sex-matched controls were obtained for each case from patients attending a general gastroenterology clinic within 3 months of attendance of the case, and thus 100 controls were obtained. Data on the controls were collected as for the cases.

RESULTS: Of the cases, 12 of 50 were taking statins compared with 20 of 100 controls (matched OR 1.13, CI 0.30-4.24, NS). Coronary artery disease was seen in 20 of 50 cases and 20 of 100 controls (matched OR 5.37, CI 1.52-19.0, p<0.01).

CONCLUSIONS: There was no statistically significant association between the use of statins and the diagnosis of interstitial lung disease. However there was a statistically significant association between ischaemic heart disease and the diagnosis of ILD.