While it is well documented that bariatric surgery results in a reduction in weight, glucose, and blood pressure in the months and years following the procedure, few studies have examined the longer-term impact on blood pressure [6]. In this long-term follow-up study, we have shown that beyond 5 years after bariatric surgery, the requirement for blood pressure-lowering treatment starts to rise again, indicating a need for continued close monitoring of individuals in the years following bariatric surgery.

Our findings agree with the 2004 report from Sjöström et al. [7] showing that at 10 years after bariatric surgery follow-up, the proportion of patients with reversed hypertension decreased from 34% at 2 years to 19% at 10 years and also with Mingrone et al. [8] who reported that weight and HbA1c had started to increase by 10-year follow-up. The primary outcome in our study was the number of antihypertensive medications prescribed in order to maintain blood pressure on target.

A recent meta-analysis of studies examining the influence of bariatric surgery on blood pressure control [9] described a mean follow-up period of 2.2 years with maximum follow-up duration of 10 years. The meta-analysis concluded that Roux-en-Y gastric bypass surgery has the most certain efficacy on blood pressure reduction among all surgeries and should be the first-choice operation type for patients with obesity and hypertension. The median follow-up period in our study was 11.5 years, which is significantly greater than the follow-up period for most previous studies.

Weight loss following bariatric surgery has been associated with left ventricular reverse remodeling and improved longitudinal biventricular mechanics [10]. Thus, in addition to routinely measured factors, the effects of bariatric surgery on cardiac structure and function need to be taken into account, although we were not able to look at that here.

Following the systematic review published by Buchwald et al. in 2004 [11], which included a total of 22,094 patients, it has been accepted that approximately three of every five subjects undergoing BS achieve hypertension ‘remission’. However, it must be considered that this meta-analysis mainly included studies with a short-term follow-up, with the surgical procedures performed up to that point in time (gastric bypass (GB), gastric band, and biliopancreatic diversion). Furthermore, most studies were retrospective and with great heterogeneity regarding the definition of hypertension remission.

Five randomized controlled trials (RCTs) [12,13,14,15,16] also assessed the effects of BS in subjects with class I obesity, observing positive results in blood pressure evolution, nearly equivalent to those obtained in patients with body mass index > 35 kg/m2. However, the main limitation when evaluating these data was the heterogeneity of the definitions used for remission or improvement in the different studies, as some considered total withdrawal of antihypertensive medication and others only blood pressure normalization.

Regarding the mid- and long-term effects of bariatric surgery, less evidence exists on the mid- (3–5 years) and long-term (> 5 years) effects of BS on hypertension remission compared to other obesity comorbidities such as type 2 diabetes. In accordance with our findings at 5 years post-surgery, Mingrone et al. [17] found that the BS group and conventional treatment maintained similar blood pressure levels 60 months after surgery.

The strengths of our study include a significantly long follow-up period, enough to capture statistically significant changes in BP with a hypertensive cohort. To our knowledge, this is the longest such follow-up cohort study to date in the UK.

We acknowledge the previously reported findings that weight loss following bariatric surgery is associated with left ventricular reverse remodeling and improved longitudinal biventricular mechanics [10]. Thus, in addition to routinely measured factors, the effects of bariatric surgery on cardiac structure and function need to be taken into account. We did not have these measures in relation to the patients in our study, nor do we have serological measures of vascular health or physical measures beyond BP.

It should be stated that one observational study (n = 2010) suggested that as many as 44% of patients who experience initial remission of hype tension will have a recurrence and need to restart antihypertensive medications within 10 years, this is likely driven by aging as well as weight regain [7].

Regarding confounding variables, we accept that this is a single-center study and that there is an inherent potential bias in the fact that the individuals were recruited sequentially. We were not able to control for the number of antihypertensive agents prescribed at baseline. Nevertheless, the group is representative of our cohort of bariatric patients overall. We did not have access to electrocardiography on a routine basis, which is a limitation. Finally, this was not a randomized clinical trial and we were not able to compare nodes of bariatric intervention in relation to the outcome measures because of the low numbers undergoing sleeve gastrectomy and gastric banding.