MBS improved hypertension outcomes, lowering use of antihypertensive medications

Patients with hypertension who underwent metabolic and bariatric surgery (MBS) had improved hypertension outcomes, demonstrating improvements in BMI and blood pressure control, according to research from the Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA.

The study’s researchers added that these patients had higher rates of antihypertensive medications (AHMs) discontinuation and lower rates of apparent treatment resistant hypertension (ATRH). They concluded the findings further validate the role of MBS in the management of cardiovascular morbidity in patients with obesity.

The researchers stated that although the GATEWAY (Gastric Bypass to Treat Obese Patients With Steady Hypertension) Trial found that RYGB patients were significantly more likely to reduce AHM use by >30% compared to patients treated with medical therapy alone (at five years), longer term evaluation of hypertension outcomes across large real world populations of patients treated with MBS is necessary to understand the durability and external validity of these findings.

In their retrospective cohort study, they assessed rates of adequate blood pressure control, AHM use and ATRH based on receipt of MBS over a period of 17 years amongst Veterans with obesity and hypertension. They sought to characterise the relative effect of MBS on blood pressure, AHM discontinuation and likelihood of developing ATRH compared to patients who did not undergo MBS. They hypothesised that patients who received MBS would experience improved blood pressure control, lower AHM prescription rates and lower likelihood of developing ATRH.

The overall cohort included 187,667 patients with a diagnosis of hypertension and a BMI ≥ 35 kg/m2: 183,702 individuals who were managed medically and 3,965 individuals who received MBS. Across the entire cohort, the median duration of follow-up was 5.1 (IQR 2.2–9.1) years. In the surgical cohort, the median time to MBS from index date was 4.2 (IQR 1.8–7.4) years with a median duration of follow-up post-MBS of 2.6 (1.0–5.4) years.

At baseline, patients who received MBS were more likely to be female (22 vs 10%, p<0.001), slightly younger (54 vs. 55 years, p<0.001), had slightly lower blood pressures (139 vs. 140 mm Hg systolic and 82 vs. 83 mm Hg diastolic, p < 0.001) and were prescribed slightly fewer AHMs (1.5 vs. 1.6, p<0.001) at baseline than medical patients.

At the index date, both the surgical and medical cohorts demonstrated elevated blood pressures with the same mean systolic blood pressures of 140 mm Hg and mean diastolic blood pressures of 83 mm Hg. Time-updated analyses revealed that MBS patients had better blood pressure control throughout the study period. Average systolic blood pressure was 5.4 mm Hg (95% CI -5.9 to -4.9 mm Hg) lower and average diastolic blood pressure was 1.8 mm Hg (95% CI -2.1 to -1.5 mm Hg) lower in those who underwent MBS vs. medical therapy over the duration of follow-up.

Overall, improvements in BMI in the MBS cohort correlated with improvements in blood pressure control (Figure 1). Patients lost the majority of their excess weight in the first six months after surgery with a corresponding drop in mean blood pressure. The researchers noted that over the following 4.5 years, both BMI and blood pressure measurements remained relatively stable, indicating a durable effect. In non-MBS patients, there was no drop in BMI, though mild improvements in SBP and DBP could be detected. There was no effect modification by sex, age, race, obesity severity or baseline diabetes status.

Figure 2: Trends in mean body mass index, systolic blood pressure and diastolic blood pressure over six-month bins in patients managed with bariatric surgery versus medically with a minimum of 5 years of follow-up. Note that “Month 0” represents the mean values from the year prior to bariatric surgery in MBS patients and one year prior to index date in non-surgical patients.

Surgery was also associated with lower AHM requirements over time when adjusted for time-updated blood pressure control. Patients who underwent MBS were on an average of 0.48 (95% CI -0.86 to -0.10) fewer AHMs during follow-up vs non-surgical patients. Surgical patients had a 32% greater likelihood of discontinuing AHMs entirely (7.0 vs. 5.5 events per 100 person-years; adjusted hazard ratio [HR] 1.32, 95% CI 1.23–1.42) and 14% lower likelihood of developing ATRH (7.3 vs. 9.7 events per 100 person-years; adjusted HR 0.86, 95% CI 0.78–0.95). There was no effect modification by sex, age or baseline diabetes status.

“In this study, improvements in blood pressure over time seemingly correlated with drops in BMI, perhaps implying that loss of excess weight had greater impact on blood pressure control than any other hormonal effects of MBS,” the researchers stated. “Comparing the effect of MBS vs. glucagon-like peptide 1 agonists vs. combination therapy with both modalities on hypertension outcomes will be an important avenue for future research.”

The findings were reported in the paper, ‘The Effect of Bariatric Surgery on Hypertension Outcomes: A Retrospective Cohort Study’, published in the Journal of Human Hypertension. To access this paper, please click here