PURPOSE: The severity of obstructive sleep apnea is much higher in chronic obstructive pulmonary disease (COPD) patients than in general population. The purpose of this study was to compare the severity of obstructive sleep apnea in two groups of COPD patients: group I, COPD with cor pulmonale; and group II, COPD without cor pulmonale.
METHODS: DESIGN: A case control study. SETTING: Referral sleep laboratory of Vallabhbhai Patel Chest Institute, Delhi University, Delhi, India. PATIENTS: 21 patients of COPD with cor pulmonale (mean pulmonary artery pressure > 25 mm Hg) and 29 patients of COPD without cor pulmonale were taken. MEASUREMENTS: Whole night polysomnography (Medcare polygraph, Medcare Flaga, Reykjavik, Iceland) was done in all the patients. Obstructive sleep apnea was defined as severe if the apnea-hypopnea index was more than 30 per hour.
RESULTS: Three out of 21 (14.28%) patients in cor pulmonale group and none out of 29 patients in COPD group had severe obstructive sleep apnea (p= 0.068).
CONCLUSION: There is no significant increase in severity of obstructive sleep apnea in COPD patients who develop cor pulmonale in the natural course of disease. We hypothesize that decrease in body mass index during the natural course of COPD counterbalances the increase in AHI due to progression of COPD to cor pulmonale.
CLINICAL IMPLICATIONS: There is no risk of increase in severity of obstructive sleep apnea-hypopnea syndrome in the natural course of COPD.
DISCLOSURE: Amit Bansal, No Financial Disclosure Information; No Product/Research Disclosure Information