and all‐cause mortality, according to a retrospective cohort study.
“These factors should be taken into account when considering the management and prognosis of these patients,” the researchers said in the Clinical Respiratory Journal.
Prior studies have found that patients with COPD and OSA – that is, with overlap syndrome – “have a substantially greater risk of morbidity and mortality, compared to those with either COPD or OSA alone,” said Philippe E. Jaoude, MD, and Ali A. El Solh, MD, both of the Veterans Affairs Western New York Healthcare System in Buffalo and the University at Buffalo.
To identify factors associated with COPD exacerbation and all‐cause mortality in patients with overlap syndrome, Dr. Jaoude and Dr. El Solh reviewed the electronic health records of patients with simultaneous COPD and OSA. They compared patients with overlap syndrome who had an acute exacerbation of COPD during a 42-month period with a control group of patients with overlap syndrome who did not have exacerbations during that time. Patients with exacerbations and controls were matched 1:1 by age and body mass index.
Eligible patients were aged 42-90 years, had objectively confirmed COPD, and had documented OSA by in-laboratory polysomnography (that is, at least five obstructive apneas and hypopneas per hour). The investigators defined a COPD exacerbation as a sustained worsening of a patient’s respiratory condition that warranted additional treatment.
Of 225 eligible patients, 92 had at least one COPD exacerbation between March 2014 and September 2017. Patients with COPD exacerbation and controls had a mean age of about 68 years. The group of patients with exacerbation had a higher percentage of active smokers (21% vs. 9%) and had poorer lung function (mean forced expiratory volume in 1 second percent predicted: 55.2% vs. 64.5%).
“Although the rate of CPAP adherence between the two groups was not significantly different, the average time of CPAP use was significantly higher in patients with no recorded exacerbation,” the researchers reported – 285.4 min/night versus 238.2 min/night.
In all, 146 patients (79.4%) survived, and 38 patients (20.6%) died during the study period. The crude mortality rate was significantly higher in the group with COPD exacerbations (14% vs. 7%).
“Multivariate logistic regression analysis identified the independent risk factors associated with COPD exacerbations as active smoking, worse airflow limitation, and lower CPAP utilization,” they said. “As for all-cause mortality, a higher burden of comorbidities, worse airflow limitation, and lower time of CPAP use were independently associated with poor outcome.”
The researchers noted that they cannot rule out the possibility that patients who were adherent to CPAP were systematically different from those who were not.
The authors had no conflicts of interest.
SOURCE: Jaoude P et al. Clin Respir J. 2019 Aug 22. doi: 10.1111/crj.13079.