Pulmonary function tests as predictors of mortality in patients with sarcoidosis

Introduction: The extent and severity of lung involvement; the most common presentation of sarcoidosis, is clinically evaluated in combination with interpretation of lung function tests (LFTs) and chest imaging. The prevalence of ventilatory patterns and the prognostic ability of lung function indices in a population of biopsy proven sarcoidosis patients was assessed. Methods: Consecutive adult sarcoidosis patients that attended the outpatient sarcoidosis clinic and performed LFTs according to ERS/ATS guidelines between October 2006 and May 2014 were considered eligible. Results: A total of 321 sarcoidosis patients (121 males, 47.3±12.2 years old) were enrolled. Mean values (±SD) of pulmonary function tests parameters were as follows: FEV1:92.2±18.3%, FVC 96.1±18.4%, FEV1/FVC:80.9±7.7%, TLC:84.8±15.8%, RV:82.2±22.4, TLCO:78.9±18.4% and KCO:97.5±17.3%. The CPI index was 20.7±13.6. 31% of patients presented with restrictive pattern, 3% with obstructive and 2.5% with mixed ventilatory pattern. An optimal threshold of CPI >40 was the best independent predictor of mortality irrespective of ventilatory patterns during a follow time of 58.2±29.6 months. Conclusion: An index of pulmonary function variables that correlates with extent of interstitial disease on high-resolution computed tomography is the strongest predictor of mortality than any individual lung function variable or ventilatory pattern.