Gender differences in outcomes of ambulatory and hospitalized patient with obesity hypoventilation syndrome

Obesity hypoventilation syndrome (OHS) is associated with high morbidity and mortality. There is a paucity of data on whether there are gender differences in outcomes. Research Question Is female gender associated with worse outcomes in ambulatory and hospitalized patients with OHS? We performed post hoc analyses on two separate OHS cohorts: 1) stable ambulatory patients from the two Pickwick randomized controlled trials and 2) hospitalized patients with acute-on-chronic hypercapnic respiratory failure from a retrospective international cohort. We first conducted bivariate analyses of baseline characteristics and therapeutics between genders. Variables of interest from these analyses were then grouped into linear mixed effects models, Cox proportional hazards models or logistic regression models to assess the association of gender on various clinical outcomes. The ambulatory prospective cohort included 300 patients (64% female) and the hospitalized retrospective cohort included 1,162 patients (58% female). For both cohorts, women were significantly older and more obese than men. Compared to men, baseline PaCO was similar in ambulatory patients, but higher in hospitalized women. In the ambulatory cohort, in unadjusted analysis, women had increased risk of emergency room visits. However, gender was not associated with the composite outcome of emergency room visit, hospitalization, or all-cause mortality in the fully adjusted model. In the hospitalized cohort, positive airway pressure (PAP) prescription was less prevalent in women upon discharge. In unadjusted analysis, hospitalized women had a higher mortality at 3, 6, and 12 months after hospital discharge compared to men. However, after adjusting for age, gender was not associated with mortality. Although the diagnosis of OHS is established at a more advanced age in women, gender is not independently associated with worse clinical outcomes after adjusting for age. Future studies are needed to examine gender-related health disparities in diagnosis and treatment of OHS.