Early and long-term clinical outcomes of bilio-intestinal diversion in morbidly obese patients

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.

Evaluation and Management of Obesity Hypoventilation Syndrome. An Official American Thoracic Society Clinical Practice Guideline

Background: The purpose of this guideline is to optimize evaluation and management of patients with obesity hypoventilation syndrome (OHS).Methods: A multidisciplinary panel identified and prioritized five clinical questions. The panel performed systematic reviews of available studies (up to July 2018) and followed the Grading of Recommendations, Assessment, Development, and Evaluation evidence-to-decision framework to develop recommendations. All panel members discussed and approved the recommendations.Recommendations: After considering the overall very low quality of the evidence, the panel made five conditional recommendations. We suggest that: 1) clinicians use a serum bicarbonate level <27 mmol/L to exclude the diagnosis of OHS in obese patients with sleep-disordered breathing when suspicion for OHS is not very high (<20%) but to measure arterial blood gases in patients strongly suspected of having OHS, 2) stable ambulatory patients with OHS receive positive airway pressure (PAP), 3) continuous positive airway pressure (CPAP) rather than noninvasive ventilation be offered as the first-line treatment to stable ambulatory patients with OHS and coexistent severe obstructive sleep apnea, 4) patients hospitalized with respiratory failure and suspected of having OHS be discharged with noninvasive ventilation until they undergo outpatient diagnostic procedures and PAP titration in the sleep laboratory (ideally within 2-3 mo), and 5) patients with OHS use weight-loss interventions that produce sustained weight loss of 25% to 30% of body weight to achieve resolution of OHS (which is more likely to be obtained with bariatric surgery).Conclusions: Clinicians may use these recommendations, on the basis of the best available evidence, to guide management and improve outcomes among patients with OHS.

Obesity Hypoventilation Syndrome

Obesity hypoventilation syndrome is a respiratory consequence of morbid obesity that is characterized by alveolar hypoventilation during sleep and wakefulness. The disorder involves a complex interaction between impaired respiratory mechanics, ventilatory drive and sleep-disordered breathing. Early diagnosis and treatment is important, because delay in treatment is associated with significant mortality and morbidity. Available treatment options include non-invasive positive airway pressure (PAP) therapies and weight loss. There is limited long-term data regarding the effectiveness of such therapies. This review outlines the current concepts of clinical presentation, diagnostic and management strategies to help identify and treat patients with obesity-hypoventilation syndromes.