Association of obstructive sleep apnea risk or diagnosis with daytime asthma in adults

Abstract

Objective: Obstructive sleep apnea (OSA) worsens nocturnal asthma, but its potential impact on daytime asthma remains largely unassessed. We investigated whether the sleep disorder is associated with daytime, in addition to nighttime, asthma symptoms.

Methods: Asthma patients at tertiary-care centers completed the Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ), and an asthma control questionnaire. SA-SDQ scores ≥36 for males and ≥32 for females defined high OSA risk. Medical records were reviewed for established diagnosis of OSA and continuous positive airway pressure (CPAP) use.

Results: Among 752 asthma patients, high OSA risk was associated similarly with persistent daytime and nighttime asthma symptoms (p < .0001 for each). A diagnosis of OSA was robustly associated with persistent daytime (p < .0001) in addition to nighttime (p = .0008) asthma symptoms. In regression models that included obesity and other known asthma aggravators, high OSA risk retained associations with persistent daytime (odds ratio [OR] = 1.96 [95% confidence interval [CI] = 1.31-2.94]) and nighttime (1.97 [1.32-2.94]) asthma symptoms. Diagnosed OSA retained an association with persistent daytime (2.08 [1.13-3.82]) but not with nighttime (1.48 [0.82-2.69]) asthma symptoms. CPAP use was associated with lower likelihood of persistent daytime symptoms (0.46 [0.23-0.94]).

Conclusions: Questionnaire-defined OSA risk and historical diagnosis were each associated with persistent daytime asthma symptoms, to an extent that matched or exceeded associations with nighttime asthma symptoms. Unrecognized OSA may be a reason for persistent asthma symptoms during the day as well as the night.

Figures

Figure 1

Prevalence of persistent asthma symptoms in asthma subjects with (n=212) and without (n=540) high OSA risk. † p<0.0001 when compared to subjects without high OSA risk and with persistent daytime asthma symptoms; ‡ p<0.0001 when compared to subjects without high OSA risk and with persistent nighttime asthma symptoms. High OSA risk=scores on Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ) ≥36 for men and ≥32 for females; OSA= obstructive sleep apnea.

Figure 2

Prevalence of persistent asthma symptoms in asthma subjects without (n=692) and with (n=60) diagnosed and untreated OSA. † p<0.0001 when compared to subjects without OSA and with persistent daytime asthma symptoms; ‡ p=0.0006 when compared to subjects without OSA and with persistent nighttime asthma symptoms. OSA= obstructive sleep apnea.