Sleep Apnea Serves as a Risk Factor for Uncontrolled, Severe Asthma

Asthma is more likely to be uncontrolled or severe in adults who are at high risk for obstructive sleep apnea (OSA), according to a new study.¹

To analyze the frequency of high-risk for OSA in asthma patients and how it impacts asthma severity and control, investigators, led by Gonçalo Martins dos Santos, from the department of allergy and clinical immunology at Centro Hospitalar Universitário de Lisboa Central EPE in Lisbon, Portugal, conducted a cross-sectional study at an allergy department with adult asthma patients.

“According to our findings, it is crucial to screen asthma patients for OSA, especially those with uncontrolled asthma and uncontrolled rhinitis who are women and comply with [Global Initiative for Asthma] treatment levels 4-5,” wrote the investigators.

Sleep apnea, affecting 39 million US adults, is a comorbidity of asthma.2 The prevalence of OSA in asthma patients is 2 – 3 times greater than in patients without asthma.1 Previous studies found the presence of OSA in asthma patients was linked to poorer asthma control, worsened symptoms, and more emergency department visits or hospital admissions.

In the current study, participants were recruited to the department while undergoing routine lung function tests from January 2022 – December 2022. Participants were ≥ 18 years old, had a medical diagnosis of asthma, an asthma A2 score of ≥ 22, and had to be able to perform a spirometry.

The team gathered data on sex, age, body mass index, allergen sensitization, smoking habits, risk of OSA (Berlin questionnaire), rhinitis control (Control of Allergic Rhinitis and Asthma Test), asthma severity (Global Initiative for Asthma 2023), asthma control (Asthma Control Test), adherence to asthma treatment (Treatment Adherence Measure), and pulmonary function test results. Participants completed self-reported questionnaires answering sociodemographic questions and medical history.

The study included 216 patients with 70.4% women, a median BMI of 24.6 kg/m2, and a mean age of 29 years old. In the cohort, 28.2% were on the global initiative for asthma treatment levels 4-5, 75.5% had controlled asthma, 34.7% had controlled rhinitis, and 21.8% had high-risk for OSA.

Individuals were more likely to be at high risk for OSA if they were women (83%; n = 39, P = .046), older (P = .001), and had a greater BMI (P < .001). Moreover, 70% of individuals at high risk for OSA had obesity.

“We should emphasize that 30% of high-risk for OSA patients were not obese, suggesting that this single characteristic should not be considered synonymous with OSA,” investigators wrote.

Patients at high risk for OSA were more likely to have uncontrolled (47.8% vs. 15.8%; P < .001) and more severe asthma (44.7% vs. 23.7%; P =.006). As for the multivariable analysis, being high-risk for OSA (odds ratio [OR], 2.81; 95% confidence interval [CI], 1.28 – 6.17, P = .010), women (OR, 5.21; 95% CI, 1.70 – 15.96, P = .004), having uncontrolled rhinitis (OR, 3.65; 95% CI, 1.38 – 9.64, P = .009, and Global Initiative for Asthma treatment steps 4-5 (OR, 2.46; 95% CI 1.15 – 5.26, P = .020) were linked to increased likelihood of having uncontrolled asthma.

The investigators addressed multiple limitations, such as not being able to generalize results to general asthma patients as the team conducted the study in an allergy and clinical immunology department. Additionally, because participants completed self-reported questionnaires, answers may not have been accurate. Despite the limitations, the investigators stressed the importance of looking for OSA in asthma patients.

“The presence of OSA may be associated with worse outcomes in asthma patients, as a higher rate of severe asthma exacerbations, a higher risk of non-invasive positive pressure ventilation and longer length of hospital stay, a higher risk of readmission after hospitalization for an asthma exacerbation,” investigators wrote. “Therefore, it is important to identify asthma patients with OSA, as its treatment has positive effects on asthma symptoms, asthma control and severity, as well as quality of life.”

^References

1. ^{Martins Dos Santos G, Simão Coelho P, Gaspar Marques J, et al. Obstructive Sleep Apnea: a risk for uncontrolled and more severe asthma in adults that we should keep an eye on. Eur Ann Allergy Clin Immunol. Published online January 15, 2024. doi:10.23822/EurAnnACI.1764-1489.324}
2. ^{Sleep Apnea Statistics and Facts. The National Council on Aging. October 11, 2023. https://www.ncoa.org/adviser/sleep/sleep-apnea-statistics/#:~:text=Approximately%2039%20million%20U.S.%20adults,have%20mild%20to%20severe%20OSA. Accessed January 17, 2024.}