The Pickwick randomized clinical trial: long-term positive airway pressure therapy in obesity hypoventilation syndrome

Abstract

Rationale: Obesity hypoventilation syndrome (OHS) is commonly treated with CPAP or noninvasive ventilation (NIV). NIV is more complex and costly but it provides ventilatory support. To date there have been no long-term trials comparing these treatment modalities.

Methods: We performed a large, multicenter, open-label controlled trial in Spain to compare the long-term effectiveness of NIV and CPAP: respiratory function, Epworth sleepness scale (ESS), other clinical symptoms, blood pressure (BP) and health related quality of life (HRQL). The analysis was performed according to the intention-to-treat principle.

Results: In total, 215 patients with untreated OHS and severe obstructive sleep apnea (OSH) were randomized to NIV or CPAP therapy and followed at least 3 years. PaCO2, bicarbonate and pH improved significantly with both treatments without group differences. FEV1 and FVC improved with positive airway pressure (PAP) but without significant group differences. The 6-MWD test did not improve with either PAP modality and there were no significant group differences. ESS and other clinical symptoms like dyspnea or unrefreshing sleep improved similarly with CPAP and NIV therapy. Both systolic and diastolic BP improved significantly with PAP but without group differences. HRQL tests (SF-36 physical and mental, FOSQ and VAWS) improved with PAP without any significant group differences.

Conclusions: In stable patients with OHS and severe OSA, NIV and CPAP have similar long-term effectiveness improving respiratory function, symptoms, BP and HRQL. Given that CPAP has lower complexity and cost, CPAP may be the preferred treatment modality until more studies become available.