Weight Loss Interventions as Treatment of Obesity Hypoventilation Syndrome. A Systematic Review.

Rationale: Obesity hypoventilation syndrome (OHS) is an undesirable consequence of obesity. Weight loss is an important component of management based on clinical rationale, but the evidence supporting weight loss has not been summarized and the optimal approach has not been determined.Objectives: This systematic review informed an international, multidisciplinary panel of experts who had converged to develop a clinical practice guideline on OHS for the American Thoracic Society. The panel asked, "Should a weight loss intervention be performed in patients with OHS?"Methods: Medline, the Cochrane Library, and Embase were searched from January 1946 to March 2019 for studies that assessed weight loss interventions in obese adults with confirmed OHS, suspected OHS, or hypercapnia. The quality of the evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.Results: The search identified 2,994 articles. Six studies were selected, including two randomized trials and four nonrandomized studies without a comparator. Sample size ranged from 16 to 63 subjects. The studies found that a comprehensive weight loss program (including motivational counseling, dieting, and exercise) can reduce weight by 6% to 7% but confers no clinically significant effects compared with standard care. Bariatric surgery, on the other hand, is associated with more robust weight loss (15-64.6%, depending on the type of intervention), reduction of obstructive sleep apnea severity (18-44% reduction of the apnea-hypopnea index), and improvement in gas exchange (17-20% reduction in partial pressure of carbon dioxide in the arterial blood), ultimately leading to the resolution of OHS. Moreover, daytime sleepiness and pulmonary artery pressure also improve with significant weight loss. Bariatric surgery is associated with adverse effects in roughly one-fifth of patients, but serious adverse effects are very rare. The level of certainty in the estimated effects was very low for most outcomes.Conclusions: The guideline panel for which the systematic review was performed made a conditional (i.e., weak) recommendation suggesting a weight loss intervention for patients with OHS, targeting a sustained weight loss of 25% to 30% of actual body weight. This recommendation was based on very low-quality evidence. Although the weight loss target is based on the observation that greater weight loss is associated with better outcomes, there is a need for better-quality studies to ascertain the degree of weight loss necessary to achieve improvement in clinically relevant outcomes in patients with OHS.

The Role of Positive Airway Pressure Therapy in Adults with Obesity Hypoventilation Syndrome. A Systematic Review and Meta-Analysis.

Rationale: Obesity hypoventilation syndrome (OHS) is an undesirable complication of severe obesity. Although weight loss is an accepted component of management, it is difficult to achieve and sustain the degree of weight loss necessary to reverse OHS. As such, positive airway pressure (PAP) during sleep has become the cornerstone therapy for most patients with OHS. However, the value of PAP therapy remains uncertain.Objective: To perform a systematic review to determine whether adults with OHS should be treated with PAP therapy or not.Methods: This systematic review informed an international, multidisciplinary panel of experts who had converged to develop a clinical practice guideline on OHS for the American Thoracic Society. MEDLINE, the Cochrane Library, and Embase were searched from January 1946 to March 2019 for studies that compared PAP therapy (i.e., continuous PAP or noninvasive ventilation) to no PAP therapy in patients with OHS. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to appraise the quality of evidence.Results: The search identified 2,994 unique articles. The full text of 56 articles was reviewed, and 25 studies were selected, including 3 randomized trials, 12 nonrandomized comparative studies, and 10 randomized and nonrandomized studies without a comparator group. Sample size ranged from 21 to 1,527 patients. PAP was associated with increased resolution of OHS and improvements in mortality, gas exchange, daytime sleepiness, sleep quality, quality of life, and emergency department visits. Nearly half of patients experienced trivial adverse effects related to PAP therapy. Certainty in the estimated effects was low or very low for most outcomes.Conclusions: The panel made a conditional (i.e., weak) recommendation that PAP therapy during sleep be offered to patients with OHS to improve outcomes. This recommendation was based on very low-quality evidence.