CPAP adherence and partial upper airway obstruction during sleep.

Nasal continuous positive airway pressure (CPAP) is the treatment of choice in severe obstructive sleep-disordered breathing (SDB). Partial obstruction is usually considered as mild SDB with poor CPAP adherence. In a retrospective study, we investigated the occurrence of partial obstruction in 233 age and BMI-matched male-female pairs and its impact on CPAP adherence after one year using static-charge-sensitive bed. Women had less SDB compared with men (21.8 vs 31.7% of time in bed (TIB), p < 0.001), less periodic breathing (5.8 vs 15.6%, p < 0.001) but tended to have more partial obstruction (10.5 vs 7.5%, p = 0.174). In women, partial obstruction accounted for 50.2% of breathing abnormalities, in men 37.2% (p < 0.001). CPAP adherence was 60.5% in women and 56.9% in men. When taking into account the proportion of partial obstruction (< or = 5 vs > 5% of TIB) or periodic breathing, there were no differences in women's CPAP adherence (p = 0.130 and p = 0.148, respectively). Men with periodic breathing over 5% of TIB tended to be more adherent to CPAP, (p = 0.052). The high occurrence of partial obstruction in both genders and particularly in women suggests that the apnea-hypopnea index underestimates the occurrence of SDB. There are no concerns of low adherence when treating symptomatic partial obstruction during sleep. Partial obstruction may not represent mild SDB but a different entity.