Microalbuminuria in Patients with Obstructive Sleep Apnea-Chronic Obstructive Pulmonary Disease Overlap Syndrome.

<bold>Rationale: </bold>Microalbuminuria is said to reflect systemic vascular damage and endothelial dysfunction and is an established indicator of cardiovascular morbidity and mortality. Patients with obstructive sleep apnea (OSA)-chronic obstructive pulmonary disease (COPD) overlap syndrome have worse survival than those with OSA or COPD alone.<bold>Objectives: </bold>This study evaluated the association between overlap syndrome and microalbuminuria.<bold>Methods: </bold>Data on patients in whom OSA was suspected and who underwent polysomnography between January 2010 and December 2012 were reviewed. Microalbuminuria was defined as an albumin-creatinine ratio between 20 and 299 mg/g in men and between 30 and 299 mg/g in women.<bold>Measurements and Main Results: </bold>Of 740 consecutive patients, 344 were analyzed. Sixty-four were control participants, 248 had OSA only, 4 had COPD only, and 28 had OSA-COPD overlap syndrome. Prevalence of microalbuminuria significantly increased in the order of control, OSA, and overlap syndrome groups (3.1, 12.9, and 32.1%, respectively; P = 0.0006). After adjusting for age and sex, multivariate logistic regression analysis demonstrated a significant association of overlap syndrome with microalbuminuria compared with OSA (odds ratio, 2.61; 95% confidence interval, 1.02-6.38; P = 0.047), but after adjusting for other confounding factors, the difference in the association did not reach significance (odds ratio, 2.54; 95% confidence interval, 0.93-6.72; P = 0.070). Of 63 patients reevaluated after 3 months of continuous positive airway pressure therapy, the logarithm of the albumin-creatinine ratio in 36 patients with good compliance significantly decreased, but there was no difference in patients with poor compliance.<bold>Conclusions: </bold>OSA-COPD overlap syndrome was more prevalent than OSA alone in patients with microalbuminuria, but the difference might be mediated by conventional risk factors rather than the addition of COPD itself. [ABSTRACT FROM AUTHOR]