Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea(OSA) are common disorders ,the co-existence of both conditions is called overlap syndrome Smoking , obesity , airway resistance and inflammation are considered risk factors for both conditions ,interestingly either COPD and OSA are associated with increased cardiovascular complications with further increased risk in overlap syndrome Multiple theories could explain that one disorder can predispose or exaggerate the other. For example, in COPD cigarette smoking and inhaled steroids are linked to myopathy of upper airway dilator muscles. Moreover in core-pulmonale redistribution of edema fluid in supine position during sleep can also contribute to or exacerbate OSA .

On the other hand , OSA patients might smoke frequently and more heavily to compensate for excessive daytime sleepiness and to help them to lose weight , which results in exaggerated airway inflammation and exacerbate COPD. Rationale of the study was to assess the prevalence and predictors of OSA among patients with stable COPD.

Inclusion Criteria:

• All stable COPD patients

Exclusion Criteria:

• Patients with end organ failure

two groups , COPD with OAS ( OVERLAP SYNDROME) COPD without OSA