Association of obstructive sleep apnea risk with asthma control in adults

Abstract

Background: Unrecognized obstructive sleep apnea (OSA) may lead to poor asthma control despite optimal therapy. Our objective was to evaluate the relationship between OSA risk and asthma control in adults.

Methods: Patients with asthma seen routinely at tertiary-care clinic visits completed the validated Sleep Apnea Scale of the Sleep Disorders Questionnaire (SA-SDQ) and Asthma Control Questionnaire (ACQ). An ACQ score of >or= 1.5 defined not-well-controlled asthma, and an SA-SDQ score of >or= 36 for men and >or= 32 for women defined high OSA risk. Logistic regression was used to model associations of high OSA risk with not-well-controlled asthma (ACQ full version and short versions).

Results: Among 472 subjects with asthma, the mean +/- SD ACQ (full version) score was 0.87 +/- 0.90, and 80 (17%) subjects were not well controlled. Mean SA-SDQ score was 27 +/- 7, and 109 (23%) subjects met the definition of high OSA risk. High OSA risk was associated, on average, with 2.87-times higher odds for not-well-controlled asthma (ACQ full version) (95% CI, 1.54-5.32; P = .0009) after adjusting for obesity and other factors known to worsen asthma control. Similar independent associations were seen when using the short ACQ versions.

Conclusions: High OSA risk is significantly associated with not-well-controlled asthma independent of known asthma aggravators and regardless of the ACQ version used. Patients who have difficulty achieving adequate asthma control should be screened for OSA.

Figure 1.

Scores on each version of the ACQ in subjects with and without high obstructive sleep apnea risk, which is defined by Sleep Apnea Scale of the Sleep Disorders Questionnaire (SA-SDQ) scores ≥ 36 for men and ≥ 32 for women. * P < .0001. ACQ = Asthma Control Questionnaire; ACQf = ACQ full version; ACQs = ACQ symptoms alone; ACQsb = ACQ symptoms and short-acting β₂-agonist use; ACQsf = ACQ symptoms and percent predicted FEV₁; OSA = obstructive sleep apnea.

Figure 2.

Unadjusted (black) and adjusted* (gray) odds ratios (95% CIs) for not-well-controlled asthma defined on the basis of each ACQ version, with high OSA risk (SA-SDQ scores ≥ 36 for men and ≥ 32 for women) as the predictor. * Adjustment performed for the variables included in the final model shown in Table 4. See Figure 1 legend for expansion of abbreviation.