Patients with asthma—COPD overlap syndrome, known as ACO, had a higher prevalence of both insomnia and respiratory symptoms than those with only asthma or chronic obstructive pulmonary disease (COPD), a study reported.
Having ACO was independently associated with a 2- or 3-times higher probability of having sleep-related symptoms as compared with the group without asthma or COPD, after adjustment for age, sex, body mass index (BMI), smoking history, and educational level (adjusted odds ratio 2.14—3.36; 95% CI).
It is the first study to assess the association between sleep-related symptoms and ACO, researchers wrote in PLoS ONE. They added that since sleep disturbances have a large negative effect on quality of life, it is likely that the low quality of life in ACO found in previous studies may be partly explained by poor sleep quality.
ACO was defined as having both self-reported asthma and COPD. The prevalence of ACO in the study was 1%.
The trial included 25,429 subjects, 40 years or older, who participated in 1 of 2 Northern European general population surveys. Both surveys included questions on asthma, COPD, respiratory and sleep-related symptoms, including difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening, and excessive daytime sleepiness.
The main finding was that patients with asthma and COPD overlap have a high burden of insomnia and respiratory symptoms.
The prevalence of insomnia symptoms was highest in the group with ACO overlap. This is a novel finding and has not been previously analyzed, the researchers said, even though other studies have reported a higher burden of sleep problems in both, patients with only asthma and those with only COPD.
A high prevalence of fatigue in COPD has been reported in previous studies. In a previous study by the same authors, they found that COPD was more closely associated with sleep disturbances in men than in women. In this study, however, the association between sleep disturbances and ACO was similar in both sexes, although the prevalence of sleep disturbances was higher in women in all groups.
The ACO group had a higher prevalence of wheeze than the groups with only asthma or only COPD.
As in previous studies, ACO was more common in women.
The study could be limited by the reliability of self-reported diagnoses, both for asthma and COPD. In addition, recall bias or physician misdiagnosis cannot be excluded.
Patients with ACO may need specific interventions and future studies are needed to identify the best approach, the authors said.
Mindus S, Malinovschi A, Ekerljung L, et al. Asthma and COPD overlap (ACO) is related to a high burden of sleep disturbance and respiratory symptoms: Results from the RHINE and Swedish GA2LEN surveys [published online April 2, 2018]. PLoS ONE. 2018;13(4): e0195055. doi.org/10.1371/journal.pone.0195055.