Objective To investigate the effects of obstructive sleep apnea hypopnea syndrome(OSAHS) on the mortality among the elderly with coronary heart disease(CHD).Methods Based on the polysomnographyic results and whether nasal continuous positive airway pressure(CPAP) treatment was performed or not,132 elderly with both CHD and moderate-to-severe OSAHS were divided into non-treatment group(observation group,n =97) and treatment group(n =35).In addition,70 elderly with CHD but without OSAHS were recruited as control group.Results By the end of 4 years follow-up,22 patients died of cardiovascular events,stroke and coronary artery reconstruction.According to Cox regression analysis,the mortality in treatment group was significantly lower than that in observation group,but was not significantly different from that in control group.After adjusting age and body mass index,the mortality in observation group was still significantly higher than that in control group.Conclusion Among the elderly CHD patients,those with coexisting OSAHS have a significantly higher mortality than those without OSAHS.However,once CPAP treatment is performed in the elderly with both CHD and OSAHS,the mortality of the treatment group shows no significant difference from that of the patients without OSAHS.