Does race-ethnicity moderate the relationship between CPAP adherence and functional outcomes of sleep in US veterans with obstructive sleep apnea syndrome?

Abstract

Background: Little is known about the association of race-ethnicity and the relationship of continuous positive airway pressure (CPAP) adherence with functional outcomes of sleep in American samples with obstructive sleep apnea syndrome (OSAS). This retrospective study examines whether race-ethnicity moderates the relationship between CPAP adherence and functional outcomes of sleep in OSAS.

Methods: Over 4 months, consecutive OSAS patients had CPAP data downloads and completed questionnaires (demographics, Functional Outcomes of Sleep Questionnaire [FOSQ], Epworth Sleepiness Scale [ESS], Insomnia Severity Index [ISI]) at the Miami VA sleep center. Medical diagnoses and polysomnography data were obtained from medical record. CPAP adherence was measured as mean daily hours of use. Hierarchical regression modeling was used to explore the differential impact of race-ethnicity and CPAP adherence on functional outcomes of sleep.

Results: Two hundred twenty-seven veterans (93% male, age 59 ± 11 years) were included; 142 (63%) participants self-reported as white or Hispanic, and 85 participants (37%) as black. Hierarchical regression analyses failed to show main effects for race-ethnicity or CPAP use and FOSQ scores; however, the interaction of race-ethnicity with CPAP adherence was significantly associated with the total FOSQ (p = 0.04), Social (p = 0.02), and Intimacy (p = 0.01) subscale scores. For blacks, in adjusted analyses, CPAP adherence was positively associated with Social and Intimacy FOSQ subscales; however, no significant relationship was noted between CPAP use and FOSQ scores in whites/Hispanics.

Conclusions: Race-ethnicity may moderate the relationship between CPAP adherence and some functional outcomes of sleep; however, further studies are needed.

Keywords: adherence; functional outcomes; positive airway pressure; quality of life; race-ethnicity; sleep apnea; veterans.

Figure 1. Regression lines for fully adjusted model.

A significant black race by daily CPAP use interaction was noted for total FOSQ (A) (p = 0.04), Social subscale (B) (p = 0.02), and Intimacy subscale (C) (p = 0.01). In blacks, the simple slope for the relationship between CPAP use and total FOSQ (b = 0.34, p = 0.07) was not significantly different from zero, but was significantly different for the relationship between CPAP use and Social (b = 0.09, p = 0.04) and Intimacy (b = 0.11, p = 0.04) subscales. In whites/Hispanics, the simple slopes for the relationship between CPAP use and total FOSQ (b = -0.11, p = 0.36), Social (b = -0.04, p = 0.18), and Intimacy (b = -0.06, p = 0.09) subscales were not significantly different from zero.