Overlap Syndrome: Obstructive Sleep Apnea in COPD

According to Daniel Hansson and colleagues, routine assessment of obstructive sleep apnea (OSA) in patients with chronic obstructive pulmonary disease (COPD) is not standard practice, and the coexistence of both conditions—called overlap syndrome—is common yet underdiagnosed.

Researchers evaluated the clinical impact of routine sleep assessment by peripheral arterial tonometry (PAT) in COPD. In their study, published in ERJ Open Research, the team stated OSA was highly prevalent in COPD, especially in obese male patients. According to the report, PAT was viable for sleep assessment in patients with COPD.

The study enrolled 105 patients (44% male) with COPD with mean years of age of 68.1±9 and body mass index (BMI) of 28.3±6.0 kg/m². The cohort was assessed with anthropometrics, arterial blood gas (ABG), spirometry, and PAT-based sleep tests. Investigators also identified predictors for ABG and overlap syndrome and analyzed rapid eye movement (REM)-related OSA (REM-OSA) in cases of OVS.

Evaluating OSA in Patients With COPD

A total of 49 patients (47%) with COPD had moderate-to-severe OSA with mean apnea-hypopnea index of 30.30.8 ± 18 events/h and REM-oxygen desaturation index (REM-ODI) of 26.9 ± 17 events/h. Researchers found overlap syndrome was more prevalent in m ale patients compared with female patients (59% vs 37%; P=.029).

Compared with COPD alone, patients with overlap syndrome had increased age (70.1 ± 8 vs 66.3 ± 10 years), BMI (30.0 ± 6 vs 26.4 ± 7 kg/m²), and incidence of hypertension (71% vs 45%; all P<.03), as well as decreased deep sleep (12.7 ± 7% vs 15.4 ± 6%; P=.029) and mean overnight oxygenation (90.6 ± 3% vs 92.3 ± 2%; P=.003).

Authors reported REM-ODI value was independently associated with daytime arterial carbon dioxide tension (β=0.022; P<.001), and REM-OSA was associated with increased incidence of atrial fibrillation versus no REM-OSA (25% vs 3%; P=.022).

Overall, Hansson and colleagues established overlap syndrome is highly prevalent, and suggested a strong association between REM sleep-related breathing and COPD outcomes, such as cardiovascular disease.

Related: Cortical Thinning Due to Excessive Sleepiness in OSA