Obstructive sleep apnea tied to worse asthma exacerbations

By Reuters Staff

Patients with obstructive sleep apnea (OSA) and asthma are 14 times as likely to have severe asthma exacerbations compared to asthma patients without OSA, new research shows.

"Inattention to OSA evaluations in these patients may lead to diagnostic and treatment delays and to increases in the frequency of severe acute exacerbations," Dr. Ke Hu of Renmin Hospital in Wuhan, China, and colleagues note in their report. "Thus, we hope that the findings from our study encourage practitioners to consider screening for OSA and to consider the clinical outcomes."

The findings were published online September 29 in Sleep Medicine.

Epidemiological studies have found that people with asthma are more likely to have OSA, and vice versa, Dr. Hu and his team write. "However, it remains unclear whether OSA affects severe exacerbations in patients with asthma," they add.

To investigate, they had 146 patients with asthma and 157 controls undergo full-night polysomnography, and recorded severe asthma exacerbations among the patients over a four-year period.

Twenty-eight asthma patients and 15 controls had OSA. The relative risk of OSA in patients with asthma was 2.25. Asthma patients with OSA also had more severe exacerbations, with a relative risk of 14.23. Apnea hypoxia index correlated significantly with the number of severe exacerbations.

"These are novel findings that highlight the importance of OSA assessments for patients with asthma who present with OSA indicators, such as snoring, obesity and daytime sleepiness," Dr. Hu and colleagues write.

Repeated episodes of hypoxia and re-oxygenation that occur in OSA may lead to systemic inflammation that affects the airway and aggravates asthma, the researchers suggest. "It remains unclear whether OSA alters pulmonary function, which is a risk factor for acute exacerbations," they add. "Further studies are needed to determine whether the observed increase in acute exacerbations arose as a consequence of differing incidences of OSA in asthma patients or whether OSA reduces lung function in asthma patients."

Dr. Hu did not respond to an interview request by press time.

SOURCE: http://bit.ly/2eA2epC

Sleep Med 2016.

(c) Copyright Thomson Reuters 2016. Click For Restrictions - http://about.reuters.com/fulllegal.asp