Long term positive airway pressure effectiveness in obesity hypoventilation syndrome. Pickwick study results

Background: Noninvasive ventilation (NIV) and continuous positive airway pressure (CPAP) are the habitual treatments for obesity hypoventilation syndrome (OHS). Despite differences in cost and complexity between them, there are no long-term effectiveness studies comparing both treatments. Objectives: We performed a large multicenter randomized open-labell controlled study to determine the comparative long-term effectiveness of NIV and CPAP using hospitalization days as the primary outcome measure. Methods: Sequentially screened OHS patients with severe sleep apnea were randomized into the above-mentioned arms for at least 3 years of follow-up. Hospital resources utilization, mortality, cardiovascular events incidence, dropouts, compliance and side effects were evaluated. Statistical analysis was performed using intention-to-treat protocol evaluating event/year per patient and incidence by negative binomial, logistic and Cox regressions models and survival analysis. A secundary analysis by compliance subgroups was performed. Results: 215 patients were randomized and 202 were available for primary analysis. The median follow-up was 5.42 years. The hospital days/year was 2.19±5.65 for CPAP and 1.44±3.07 for NIV (adjusted p=0.12). Other hospital resources utilization, cardiovascular events incidence, mortality, dropouts, compliance and side effects were similar between arms. The better compliance subgroup had lower hospital resources utilization and mortality regardless of the treatment used. Conclusion: NIV and CPAP have similar long-term effectiveness. Because CPAP has economical advantages and simplicity, CPAP should be the preferable treatment for OHS patients with severe OSA.