Summary Aims Every year, over 200 000 individuals undergo bariatric surgery for the treatment of extreme obesity in the United States. Several retrospective studies describe the occurrence of orthostatic intolerance (OI) syndrome after bariatric surgery. However, the incidence of this syndrome remains unknown. Materials and methods We used a prospective, de‐identified registry of 4547 patients who have undergone bariatric surgery at Vanderbilt to identify cases of new‐onset OI. Structured chart reviews were conducted for all subjects who reported new‐onset OI post surgery. Cases of OI were confirmed using an operational case definition developed by the Vanderbilt Autonomic Dysfunction Center, and autonomic function tests results were examined for evidence of impaired autonomic function. The cumulative incidence of post‐bariatric surgery OI syndrome was estimated using a life table. Results Seven hundred forty‐one of 4547 (16.3%) patients included in our cohort reported new OI symptoms after surgery. After the chart review, we confirmed the presence of post–bariatric surgery OI syndrome in 85 patients, 14 with severe OI requiring pressor agents. At 5 years post surgery, follow‐up is reduced to 15%; the unadjusted 5‐year prevalence of OI was 1.9%. The cumulative incidence of OI syndrome adjusted for loss of follow‐up was 4.2%. Most OI cases developed during weight‐stable months (±5 kg). At the time of identification, 13% of OI cases showed evidence of impaired sympathetic vasoconstrictor activity. Conclusion OI is frequent in the bariatric population, affecting 4.2% of patients within the first 5 years postoperatively. In 13% of post–bariatric surgery OI patients, there was evidence of impaired sympathetic vasoconstriction activity.

Several retrospective studies describe an orthostatic intolerance (OI) syndrome after bariatric surgery. However, its incidence remains unknown. Using a de-identified registry of 4547 bariatric surgery patients, we identified cases of OI syndrome via structured chart reviews for all subjects who reported new-onset post-operative symptoms of OI. Cases of OI were confirmed using an operational case definition developed by the Vanderbilt Autonomic Dysfunction Center, and available autonomic function test results were examined. The cumulative incidence of post-bariatric surgery OI syndrome was estimated using a life table. Of 741 patients reporting new OI symptoms after surgery, we confirmed the presence of post-bariatric surgery OI syndrome in 85 patients (1.9% of 4547), 14 with severe OI requiring pressor agents. At 5 years post-surgery, follow-up was reduced to 15% (682 of 4547), and the estimated cumulative incidence of OI syndrome adjusted for losses to follow-up was 4.2%. Most OI cases developed during relatively weight-stable months, and weight change was not significantly different between patients with and without OI syndrome (Figure 1). Of OI cases with available autonomic function test data, 52% (11 of 21) showed evidence of impaired sympathetic vasoconstrictor activity. In conclusion, new onset orthostatic intolerance is relatively frequent in the bariatric surgery population. Some patients with OI exhibit evidence of impaired autonomic function. Figure 1. Excess Weight Loss for All Bariatric Operations (solid) vs. Patients with OI Syndrome (dotted). Shaded Areas Represent 95% Confidence Interval. Rug Plot on X-axis Indicates Time of OI Onset per Patient.