Impulse oscillometry measurements are correlated to quality of life in patients with pulmonary sarcoidosis

Rationale Although airway involvement is prevalent in pulmonary Sarcoidosis, its impact on quality of life is unclear. Impulse Oscillometry (IOS) measurements may display higher sensitivity than FEV1 and other conventional markers of airway obstruction. The present study aims to explore the utility of IOS in pulmonary sarcoidosis. Methods 63 patients with pulmonary sarcoidosis were recruited from our Sarcoid clinic. IOS and lung function tests were performed by every subject on the same day, and all participants completed Leicester's Cough (LCQ) and St George's Respiratory Questionnaires (SGRQ). Correlations between IOS and questionnaire scores were measured by Spearman's rho. Results Demographics are shown in table 1 View this table: Demographics There were significant correlations between IOS measurements (R5, X5, Fres, AX) with lung volumes (FEV1%, FVC%, RV/TLC) and maximal expiratory flows (MEF75,50,25%). R5, X5, Fres, AX were more tightly linked to the total SGRQ scores (rho=0.41, -0.43, 0.38, 0.44, respectively, p<0.01) than lung function tests (rho=0.28,p=0.03 for both FVC% and RV/TLC, no significant correlation with FVE1, MEF25/50/75 and DLCO). LCQ score was correlated with the difference R5-R20 (rho=-0.32,p=0.01). Conclusion IOS measurements correlate with symptom burden more strongly than conventional lung function markers in sarcoidosis. Whether this reflects their higher sensitivity to small airway changes requires further study.