Age and sex differences in longitudinal CPAP adherence patterns

This study investigated long-term adherence to continuous positive airway pressure (CPAP) therapy among adult patients with obstructive sleep apnea (OSA), with a focus on identifying associations between age, sex, residual apnea-hypopnea index (AHI) and longitudinal compliance.

We conducted a retrospective observational analysis of adult patients from the UCSF-affiliated Inspire Health Sleep Center in Fresno, California. Participants had valid CPAP compliance data at two-time points: initial compliance and most recent follow-up (mean follow-up: 567.8 days, SD = 362.7). Compliance was measured as the percentage of days the device was used and median nightly use. Paired t-tests and hierarchical linear regression models were used to evaluate changes over time and associations with demographic and clinical variables.

Among 208 patients (mean follow-up 567.8 days), 97.1% had ≥70% compliance at baseline, decreasing to 79.3% at follow-up in the whole sample. Percent compliance did not change significantly overall (mean difference = 1.26%, p = 0.52), but median nightly usage declined (mean difference = 0.33 h, p < 0.001). Females and patients <50 years had greater reductions in compliance. Linear regression showed a 14.4-point decline in percent compliance among women <50 (p = 0.001), with smaller declines in men and older adults. Median compliance was higher among men and those ≥65 years. Logistic regression indicated reduced odds of ≥70% compliance at follow-up (OR = 0.077, p < 0.001). Residual AHI and comorbidities were not significantly associated with adherence outcomes.

Although mean percent compliance remained stable overall, median nightly use and the proportion meeting the ≥70% adherence threshold declined over time, particularly among women under 50 years of age.