Physical Activity Following Positive Airway Pressure Treatment in Adults With and Without Obesity and With Moderate-Severe Obstructive Sleep Apnea.

STUDY OBJECTIVES: To examine the level of physical activity (PA) before and following positive airway pressure (PAP) treatment in adults who have obstructive sleep apnea (OSA) with obesity versus without obesity. METHODS: Simultaneous waist accelerometer and wrist actigraphy recordings were obtained in 129 adults with obesity and 69 adults without obesity and who had OSA prior to and following 4 months of PAP therapy and in 52 patients in a control group. Primary PA measurements were average steps per day on waist accelerometry and average counts per minute (CPM) per day on wrist actigraphy. RESULTS: At baseline, participants with obesity and OSA exhibited fewer steps per day on waist accelerometer and fewer CPM per day on wrist actigraphy compared to participants without obesity and with OSA (despite similar apnea-hypopnea index between groups). Following PAP treatment, participants with OSA had modestly increased CPM per day on wrist actigraphy (17.69 [95% confidence interval (CI), 5.67-29.71], P = .005) and increased light PA time (0.26 [95% CI, 0.07-0.44] hours, P = .008) on waist accelerometer. Participants without obesity and with OSA had greater improvements in PA measures on average compared to participants with obesity and OSA, although the differences were not statistically significant. Weight increased following PAP treatment in the participants with obesity and OSA (1.71 [95% CI, 0.41-3.02] kg, P = .010) but was unchanged in the group without obesity (0.93 [95% CI, -0.89 to 2.76] kg, P = .311). CONCLUSIONS: Compared to study participants without obesity and with OSA, participants with obesity and OSA had reduced PA at baseline. PA increased significantly in participants without obesity, with OSA, and who were adherent to PAP treatment. Results indicate that treatment of OSA is unlikely to be associated with a change in PA in adults with obesity and OSA and help explain the absence of weight loss following PAP treatment in adults with OSA. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov, title: The Effects of Treating Obese and Lean Patients With Sleep Apnea (PISA), identifier: NCT01578031, URL: https://clinicaltrials.gov/ct2/show/NCT01578031.

Determinants of sleepiness in obstructive sleep apnea.

STUDY OBJECTIVES: Significant interindividual variability in sleepiness is observed in clinical populations with obstructive sleep apnea (OSA). This phenomenon is only partially explained by the apnea-hypopnea index (AHI). Understanding factors that lead to sleepiness is critical to effective management of patients with OSA. We examined demographic and other factors associated with sleepiness in OSA. METHODS: Prospective study of 283 patients with newly diagnosed OSA by polysomnography (AHI ≥ 5 per hour). Subjective sleepiness (Epworth Sleep Scale [ESS] ≥ 11) and objective sleepiness (psychomotor vigilance task [PVT] mean lapse ≥ 2) were assessed. RESULTS: Participants were classified into four groups (1: sleepy by ESS and PVT, 2: sleepy by PVT only, 3: sleepy by ESS only, and 4: nonsleepy reference group) and compared by generalized logit model. Shorter daily sleep duration by actigraphy and less morningness were associated with higher risk of sleepiness (Odds ratio [OR] = 0.52, 95% confidence interval [CI] 0.33-0.82 and OR = 0.89, CI 0.80-0.98, respectively). African-American race was associated with sleepiness (group 1, OR = 8.8, CI 2.8-27.3; group 2, OR = 16.6, CI 3.3-83.6; and group 3, OR = 3.3, CI 1.0-10.1). IL-6 level was higher in groups 1 and 3 (OR = 1.9, CI 1.0-3.4 and OR 2.0, CI 1.1-3.7, respectively). CONCLUSIONS: African-American race, short sleep duration, chronotype, and increased proinflammatory cytokine IL-6 level were associated with sleepiness in OSA. These findings will inform future investigations determining mechanisms of sleepiness in OSA.

Short-Term Variability in Apnea-Hypopnea Index during Extended Home Portable Monitoring.

STUDY OBJECTIVES: Apnea-hypopnea index (AHI) is the primary measure used to confirm a diagnosis of obstructive sleep apnea (OSA). However, there may be significant night-to-night variability (NNV) in AHI, limiting the value of AHI in clinical decision-making related to OSA management. We examined short-term NNV in AHI and its predictors during home portable monitoring (PM). METHODS: Single center prospective observational study of patients (n = 84) with newly diagnosed OSA by polysomnography (PSG) AHI ≥ 5/h. All participants underwent 2 to 8 consecutive nights of PM. RESULTS: Participants (n = 84) were middle-aged (47 ± 8.3 y, mean ± standard deviation; SD), including 28 women, with mean AHI on baseline PSG (AHIPSG) of 30.1 ± 31.8. Mean AHI on PM (AHIPM) was 27.4 ± 23.7. Intraclass correlation coefficient (ICC) for AHIPM in the entire sample was 0.73 (95% CI 0.66-0.8), indicating that 27% of the variability in AHIPM was due to intra-individual factors. Mild severity of OSA, defined by AHIPSG 5-15/h, was associated with higher NNV (likelihood ratio, -0.4 ± 0.14; p = 0.006) and absence of comorbidity showed a trend towards higher NNV (-0.54 ± 0.27, p = 0.05) on AHIPM. CONCLUSIONS: The intraindividual short-term NNV in AHIPM is higher in mild versus moderately severe OSA, even in the home setting, where first-night effect is not expected. Larger studies of NNV focused on patients with mild OSA are needed to identify characteristics that predict need and timing for repeated diagnostic testing and treatment. COMMENTARY: A commentary on this article appears in this issue on page 787.