Metabolic surgery benefits people with morbid obesity and hypertension reducing their risk of major adverse cardiovascular event (MACE), according to a study, ‘Association between metabolic surgery and cardiovascular outcome in patients with hypertension: A nationwide matched cohort study’, published in PLoS Med.
The study, led by Dr Erik Stenberg at Örebro University, Örebro, Sweden, evaluated whether metabolic surgery had cardiovascular benefits for patients with morbid obesity and hypertension, and compared two groups of people with these conditions: one that had undergone metabolic surgery, and a control group that had not.
Data was drawn from the Scandinavian Obesity Surgery Register (SOReg) to identify patients operated with primary gastric bypass or sleeve gastrectomy for morbid obesity (n=58,007) and matched (1:10) with a group of non-operated–on individuals (n=580,070). After excluding patient without hypertension and various other criteria the surgical group included 11,863 patients with hypertension operated on with metabolic surgery and a non-operated–on control group of 26,199 subjects with hypertension.
The main outcome was a major adverse cardiovascular event (MACE), defined as first occurrence of ACS (unstable angina or myocardial infarction), cerebrovascular event (subarachnoid haemorrhage, intracerebral haemorrhage, ischaemic stroke, or acute cerebrovascular disease not specified as haemorrhage or ischaemia), fatal cardiovascular or unattended sudden cardiac death.
In total, 10,692 (90.1%) patients underwent a gastric bypass procedure and 1,171 (9.9%) a sleeve gastrectomy. In total, 11,428 operations were completed with laparoscopic technique (96.3%), 301 were primarily open procedures (2.5%), and 134 were converted to open surgery (1.1%). Mean follow-up time was 61.1±30.4 months (1,834±913 days) in the surgical group and 60.7±30.6 months (1,820±918 days) for the non-surgical group. Mean BMI before surgery was 41.9±5.43 in the surgery group. Patients in metabolic surgery group were slightly younger and more often had dyslipidaemia, diabetes, COPD, and sleep apnoea but a slightly lower incidence of cerebrovascular disease.
An ACS event, cerebrovascular event, or cardiovascular death occurred in 379 operated patients (cumulative incidence at 3,000 days, 5.5%), and 1,125 subjects in the control group (cumulative incidence at 3,000 days, 7.3%) during the follow-up period. A MACE occurred in 17 patients operated on with sleeve gastrectomy (cumulative incidence at 3,000 days, 8.9%) and 362 patients operated on with gastric bypass (cumulative incidence at 3,000 days, 5.4%).
Compared with the nonsurgical patients, the risk for an MACE was reduced by approximately one-fourth (p<0.001) in the metabolic surgery group. In a subgroups analysis, patients with BMI<40 (adjusted HR 0.73, 95% CI 0.58–0.92, p=0.007), as well as those with BMI≥40 (adjusted HR 0.71, 95% CI 0.58–0.85, p<0.001), experienced lower risk for MACEs compared with the control group. Metabolic surgery resulted in a significantly reduced risk for an ACS event (adjusted HR 0.53, 95% CI 0.42–0.67, p<0.001), whilst the effect of metabolic surgery on cerebrovascular events did not reach significance (adjusted HR 0.81, 95% CI 0.66–1.01, p=0.063).
In total, 472 patients (cumulative incidence at 3,000 days, 8.0%) in the surgery group died during the follow-up period and 1,197 in the control group (cumulative incidence at 3,000 days, 8.6%); 108 patients died of a cardiovascular cause in the surgery group (cumulative incidence at 3,000 days, 2.1%) and 283 in the control group (cumulative incidence at 3,000 days, 1.9%).
A total of 10,090 patients and 22,064 controls were available for evaluation of hypertension remission rates. Amongst patients operated on with metabolic surgery, 30.7% (n=3,096) did not take medication for hypertension at any time 2–4 years after surgery, compared to 9.2% (n=2,034) in the control group. In a subgroups analysis, patients operated on with metabolic surgery with BMI<40 and BMI≥40 had higher chances of remission of hypertension compared with the control group.
Higher age, dyslipidaemia, T1DM, previous ACS, and longer duration of hypertension were all associated with lower chance of remission of hypertension, whilst higher postoperative excess BMI loss was associated with higher chance of remission.
Before surgery, median numbers of antihypertensive drugs were two in the surgery group and two in the control group. After surgery, the median number of drugs was reduced to one in the surgery group, whilst no major difference was seen in the control group.
“Metabolic surgery was associated with lower risk for a MACE and overall mortality amongst patients with hypertension and obesity at baseline compared to a matched control group with hypertension from the general population. The main effect appeared to be a reduction of ACS events…” the study concluded. “Metabolic surgery in patients with morbid obesity and hypertension decreases the risk for MACEs and all-cause mortality compared with age- and sex-matched hypertensive controls from the general population.”
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