Pulmonary function tests and impulse oscillometry in severe chronic obstructive pulmonary disease patients’ offspring

BACKGROUND Several studies have showed an increased prevalence of airflow obstruction in first degree relatives of individuals with chronic obstructive pulmonary disease (COPD). Considering no specific research had evaluated airway resistance in offspring of patients with severe COPD, we utilized a spirometry and a impulse oscillometry (IO) to evaluate this population. MATERIALS AND METHODS In this case control study, from November 2011 to July 2012, we consecutively evaluated 54 offsprings of severe COPD patients (case group) admitted in the pulmonary ward, affiliated to the Isfahan University of Medical Sciences and control group. Pulmonary function tests and the IO were obtained for both groups. Student's t-test was used for inter-group comparisons, and P values below 0.05 were taken as significant. RESULTS Abnormal increased airway resistance was seen in cases in comparison with controls (R5 Hz [46.29%, P = 0.01], R25 Hz [42.59%, P < 0.001]). Also, considering the spirometry, case group had pulmonary function parameters less than control group (forced vital capacity [FVC]; P = 0.02, forced expiratory volume in 1(st) s; P < 0.001, forced expiratory flow (FEF) 25-75; P < 0.001, FEF 25-75/FVC; P < 0.001) but they were in normal range. CONCLUSION This study demonstrated increased airway resistance among the severe COPD offsprings. The IO may be a sensitive tool for detection of high risk subjects in families with COPD.