Orthostatic intolerance after bariatric surgery: A systematic review and meta-analysis

There have been increased reports of orthostatic intolerance post-bariatric surgery. However, the prevalence, pathophysiology and long-term outcomes have not been well described. Therefore, we sought to summarize evidence of orthostatic intolerance after bariatric surgery. We conducted a systematic review using PubMed, Scopus, CINAHL, Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials (CENTRAL) to identify relevant articles from the date of inception until 1st April 2020. Study selection, data extraction and quality assessment of the included studies were performed independently by two reviewers. The findings of the included studies were narratively reported. When feasible, a meta-analysis was done to summarize the relevant results. We included 20 studies (n = 19 843 participants) reporting findings of 12 prospective cohort studies, 5 retrospective cohort studies, 2 cross-sectional studies and one randomized controlled trial. The 5-year cumulative incidence of orthostatic intolerance was 4.2% (one study). Common clinical presentations of orthostatic intolerance were lightheadedness, dizziness, syncope and palpitation. The pooled data suggested improvement in overall cardiac autonomic function (sympathetic and parasympathetic) post-bariatric surgery. In addition, a significant systolic blood pressure drop may reflect a reset of the balance between the sympathetic and parasympathetic nervous systems after weight loss in the pooled analysis. Existing literature on orthostatic intolerance post-bariatric surgeries was limited or of low quality, and larger studies are needed to know the true incidence of orthostatic intolerance post-bariatric surgeries and the pathophysiology. We found one study reporting the 5-years cumulative incidence of orthostatic intolerance post-bariatric surgeries as only 4.2%. This could challenge the idea of increased orthostatic intolerance prevalence post-bariatric surgeries. Registration The review protocol was registered at the International Prospective Register of Systemic Reviews PROSPERO (CRD42020170877).