The Association Between Adherence to Positive Airway Pressure Therapy and Long-Term Outcomes in Patients With Obesity Hypoventilation Syndrome: A Prospective Observational Study

Abstract

Study objectives: To assess the role of different levels of adherence and long-term effects of positive airway pressure (PAP) therapy on gas exchange, sleepiness, quality of life, depressive symptoms, and all-cause mortality in patients with obesity hypoventilation syndrome (OHS).

Methods: A total of 252 patients with newly diagnosed OHS were followed up for a minimum of 2 years after PAP initiation. PAP adherence (h/night) was monitored. Arterial blood gas samples were taken with patients being alert for more than 4 hours after morning awakening. Subjective daytime sleepiness (Epworth Sleepiness Scale [ESS]), quality of life (Short Form 36 [SF-36]) and patient's depressive symptoms (Beck Depression Inventory [BDI]) were assessed before and at the end of the follow-up period, along with all-cause mortality.

Results: At the end of the follow-up period (median duration [25th-75th percentile], 30 [24-52] months), PaO2 increased from baseline (72.7 ± 10.3 versus 63.2 ± 10.6, P < .001) and both PaCO2 and HCO3- decreased (43.0 [39.2-45.0] versus 50.0 [46.7-55.4] and 27.5 ± 3.2 versus 31.4 ± 4.2, respectively, P < .001). In addition, PAP therapy significantly improved ESS (7 [4-9] versus 14 [11-16], P < .001), BDI (8.8 ± 4.9 versus 15.5 ± 7.3, P < .001) and SF-36 (82 [78-87] versus 74 [67-79], P < .001) scores. Over the follow-up period 11 patients died. Patients who used PAP for > 6 h/night had significant improvements (P < .05) in blood gases and SF-36 scores than less adherent patients.

Conclusions: Increased hours of use and long-term therapy with PAP are effective in the treatment of patients with OHS. Clinicians should encourage adherence to PAP therapy in order to provide a significant improvement in clinical status and gas exchange in these patients.

Commentary: A commenary on this article appears in this issue on page 1455.

Clinical trial registration: Title: PAP Therapy in Patients With Obesity Hypoventilation Syndrome, Registry: ClinicalTrials.gov, Identifier: NCT03449641, URL: https://ichgcp.net/clinical-trials-registry/NCT03449641.

Keywords: compliance; obesity hypoventilation syndrome; positive airway pressure.

© 2018 American Academy of Sleep Medicine.

Figures

Figure 1. Study flow diagram illustrating how the final group of patients were obtained.

Figure 2. Changes in ABG at baseline and at the end of the follow-up period.

Values presented as mean ± standard deviation below graph. ABG = arterial blood gas.

Figure 3. Changes in questionnaires scores at baseline and at the end of the follow-up period.

Values presented as mean ± standard deviation below graph. BDI = Beck Depression Inventory, ESS = Epworth Sleepiness Scale, SF-36 = Short Form 36 Health Survey.

Figure 4. Changes in ABG and in questionnaires scores according to PAP compliance.

Values presented as mean ± standard deviation below graph. ABG = arterial blood gas, BDI = Beck Depression Inventory, ESS = Epworth Sleepiness Scale, PAP = positive airway pressure, SF-36 = Short Form 36 Health Survey.