A comparison of two obesity-related hypoventilation disorders – impact on sleep, quality of life and neurocognitive outcomes and the effects of PAP therapy

Symptom burden and neurocognitive function have not been previous compared between patients with obesity-associated hypoventilation disorders (obesity hypoventilation syndrome, OHS) and hypoventilation in the setting of obesity and obstructive airways disease (OHAD). The aim of this study is to compare baseline sleep-related symptoms, health-related quality of life and neurocognitive function between OHS and OHAD and the impact of PAP therapy on these outcomes. ESS, PSQI, SF36, and various neurocognitive tests, in addition to anthropometric, polysomnography, lung function and blood gas data from participants with OHS and participants with OHAD, were included in the analysis. This data was originally collected in their respective randomised clinical trials, comparing the efficacy of different PAP modes (bilevel PAP versus CPAP) in resolving hypercapnia. Between groups (OHS vs OHAD), pre- and post-treatment (with 3 months of positive airway pressure) comparisons were made using linear mixed modelling. 45 OHS participants (mean age 51yo, 33% female, BMI 52kg/m2, FER 0.81, PaCO2 54mmHg, AHI 87/hr) and 32 OHAD participants (mean age 61yo, 31% female, BMI 43kg/m2, FER 0.60, PaCO2 54mmHg, AHI 59/hr) were included in the analysis. Both OHS and OHAD had similar baseline ESS (14(5.6) vs. 12(5.4)), Global PSQI (10(3.2) vs 11(4.8)), SF36 and neurocognitive test performances (other than OHAD had lower digit symbol substitution test performance). Treatment with PAP therapy resulted in similar ESS, Global PSQI, and SF36 improvements in both groups. Neurocognitive performance did not significantly improve after PAP therapy in either group. The symptom burden between two separate hypoventilation disorders (OHS and OHAD), in terms of sleepiness, sleep quality, quality of life and cognitive function, were similar. OHS and OHAD had similar treatment responses in these parameters after 3 months of PAP therapy.