Prescribing positive airway pressure (PAP) at hospital discharge was associated with a reduction in mortality after acute-on-chronic hypercapnic respiratory failure in patients with confirmed or suspected obesity hypoventilation syndrome (OHS), according to a meta-analysis published in the Annals of the American Thoracic Society.

A systematic literature review was performed using studies that enrolled hospitalized patients with diagnosed or suspected OHS and investigated the effects of PAP. Although researchers planned on including randomized controlled trials, none were found. In total, the meta-analysis included 2 nonrandomized comparative observational studies and 7 nonrandomized noncomparative case studies. Mortality was the only outcome reported in all studies.

Collectively, there were 1275 hospitalized patients with OHS-related acute-on-chronic hypercapnic respiratory failure. Of these, individual patient data were available for 1162 patients who had survived to hospital discharge. Patients were characterized by having a discharge prescription of PAP (n=1043) or not having a discharge prescription for PAP (n=119).

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In all studies, a hospital discharge with PAP was associated with a reduction in mortality at 3 months (relative risk [RR], 0.14; 95% CI, 0.05-0.35; risk difference [RD], -14.5%), 6 months (RR, 0.24; 95% CI, 0.11-0.52; RD, -17.8%), 9 months (RR, 0.37; 95% CI, 0.21-0.64; RD, -18.6%), and 1 year (RR, 0.34; 95% CI, 0.14-0.81; RD, -21.8%).

Limitations of the meta-analysis included the lack of randomized controlled trials, the inclusion of only a small number of studies that enrolled patients consecutively, and the lack of data on mortality causes.

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The investigators concluded that “patients with OHS or suspected of having OHS hospitalized for acute-on-chronic hypercapnic respiratory failure be discharged from the hospital on empiric [noninvasive ventilation] to be used during sleep at home.”


Mokhlesi B, Masa JF, Afshar M, et al. The effect of hospital discharge with empiric noninvasive ventilation on mortality in hospitalized patients with obesity hypoventilation syndrome: an individual patient data meta-analysis [published online February 5, 2020]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201912-887OC