Bariatric surgery improves blood pressure control

1. In this randomized clinical trial, patients who received bariatric surgery were nearly 7 times more likely to achieve at least 30% reduction in the total number of hypertensive medications and nearly 20 times more likely to achieve blood pressure control without medications compared to those who did not receive surgery.

2. Patients who received bariatric surgery achieved an average weight loss of over 25%, while those who received medical therapy alone actually experienced weight gain.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Bariatric surgery is widely regarded as the most effective, durable strategy for obese patients to lose weight, and its benefits extend to other conditions including diabetes and hyperlipidemia, which often improve or resolve entirely following the procedure. Given that obesity is also a major cause of hypertension and that many patients have suboptimal adherence to antihypertensive medications, effective surgical treatment of the former may have appreciable carryover to the latter. The GATEWAY (Gastric Bypass to Treat Obese Patients with Steady Hypertension) trial was designed to investigate this association and included patients with coexisting hypertension and mild-to-moderate obesity. At 1 year, over three-quarters of patients in the gastric bypass group were able to significantly reduce their dependence on medication to maintain controlled blood pressure (BP) compared to roughly one-eighth of patients in the control group; over half of patients in the gastric bypass group showed remission of hypertension versus none in the control group. This extension study found that these between-group differences not only remained evident at 3 years but were also strikingly consistent. Roughly three-quarters of those in the gastric bypass group and one-tenth of those in the control group had reduced dependence on hypertensives. Over one-third of patients in the gastric bypass group still remained in remission, but normotension was not observed in any patients in the control group. Anemia occurred at similar rates in both groups, but nearly one-third of the gastric bypass group developed hypovitaminosis B12 and two patients required reoperation. Although this study was limited by a small sample size, a high attrition rate and the exclusion of pharmacologic obesity management alternatives, the results suggest that bariatric surgery may be an effective addition to medical therapy for hypertension control in obese patients.

Click here to read the study, published today in Annals of Internal Medicine

Relevant Reading: Effects of Bariatric Surgery in Obese Patients With Hypertension

In-Depth [randomized controlled trial]: In this single-center study performed from May 2013 to May 2016, 100 adults who had a BMI between 30 and 39.9 kg/m2 and were being treated with multiple antihypertensives for essential hypertension were blocked into 10-person groups and randomly assigned in a 1:1 ratio to receive either Roux-en-Y gastric bypass (RYGB) with standardized medical therapy (MT) or MT alone. Those who were in hypertensive crisis or had pre-existing heart disease, diabetes, or severe psychiatric disorders were excluded. 76 patients were present for the third-year visit, and the primary outcome, a reduction of at least 30% in the total number of antihypertensive medications while maintaining BP less than 140/90 mm Hg, occurred in 29 of 40 patients (73%) in the RYGB group versus only 4 of 36 patients (11%) in the MT group (relative risk, 6.52; CI, 2.50 to 17.03; P < 0.001). The complete-case analysis, which included multiply imputed data from an additional 8 patients (4 per group) who were present for the 30-month or 42-month visits, showed similar results (relative risk, 5.82; 95% CI, 2.51 to 13.47; P < 0.001). However, no significant difference between groups was found in the percentage of patients with BP less than 140/90 mmHg in either the original analysis (88% vs. 72%; relative risk, 1.21; 95% CI, 0.96 to 1.53) or the complete-case analysis (86% vs 70%; relative risk, 1.23; 95% CI, 0.98 to 1.56). Notably, 35% of patients in the RYGB group were able to achieve BP control (<130/80 mmHg) without the aid of medications, compared to only 1 patient in the MT group who later underwent RYGB (relative risk, 17.35; 95% CI, 2.34 to 128.62). The RYGB group also had a total weight loss of 27.8% with no patients gaining excessive weight, but the MT group had a total weight loss of −0.1% with 26% of patients experiencing a weight gain of >5% of the baseline value.

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