Predictors of erectile function improvement in obstructive sleep apnea patients with long-term CPAP treatment

The long-term effect of treatment with continuous positive airway pressure (CPAP) on erectile function was assessed in 60 patients with obstructive sleep apnea syndrome (OSAS). Severity of OSAS was evaluated by respiratory disturbance index (RDI) and minimal oxygen saturation (OxiMin). Severity of erectile dysfunction (ED) was assessed with the five question International Index of Erectile Function (IIEF-5) before and after CPAP treatment. Subjects were categorized into three groups on the basis of the change in IIEF-5 score: Group 1, no change (n=37); Group 2, improvement from 10+/-5.65 to 19.1+/-5.7, P<0.01 (n=12); Group 3, worsening from 19.9+/-4.7 to 9.5+/-7.8, P<0.01 (n=11). Group 2 had significantly higher RDI and lower OxiMin than the other groups, and was also more compliant and satisfied with CPAP. Change in IIEF-5 with CPAP treatment was negatively correlated (Pearson coefficient) with OxiMin (r=-0.374), and positively correlated with adherence to CPAP treatment (r=0.689). In conclusion, in selected patients, CPAP treatment for OSAS may by itself have a positive effect on erectile function by improving respiration during sleep. Predictors of erectile improvement include high RDI, low OxiMin, and CPAP compliance.