A systematic review and meta-analysis of randomised clinical trials (RCTs) underscores the superior efficacy of bariatric and metabolic surgery (BMS) over non-surgical treatments in managing obesity and associated metabolic disorders. The findings indicate that BMS significantly reduces systolic and diastolic blood pressure, fasting blood glucose, haemoglobin A1C and triglyceride levels while increasing HDL levels. Interestingly, Roux-en-Y gastric bypass procedure demonstrated the most significant impact on these outcomes.
The study authors explained that there is variability in results from previous studies, which demonstrated differences in both the extent and durability of blood pressure reduction and hypertension remission following BMS. Therefore, they conducted an extensive systematic review and meta-analysis to evaluate the comparative effectiveness of non-surgical treatment versus BMS in managing hypertension in obese individuals with this condition.
The researchers identified 29 RCTs for inclusion in the current meta-analysis and systematic review. The articles included in the review were published between 2004 and 2024. The majority of the studies were conducted in the USA (12 studies), followed by Australia (6 studies) and Brazil (5 studies). In total, this review analyzed data from 2,548 patients, with 1,249 patients in the surgical groups and 1,158 in the non-surgical groups.
Twenty-six RCTs were included in the analysis, comparing systolic blood pressure changes between surgical and non-surgical interventions. The heterogeneity was relatively high (I² = 66.7%). Patients in the surgical arms experienced a significantly greater reduction in SBP compared to those in the non-surgical arms (MD: -4.506 mmHg; 95% CI: -6.999 to -2.013; p=0.001). Sensitivity analyses using leave-one-out and fixed-effect methods also indicated significant differences in SBP changes between the surgical and non-surgical groups. However, sensitivity analysis with ten studies that had more than 50 patients in each arm did not show a significant difference between the interventions (MD: -2.939 mmHg; 95% CI: -7.199 to 1.321; p=0.15).
Subgroup analyses based on the duration of follow-up and type of bariatric surgery showed that the superiority of surgical intervention in reducing SBP remained significant in studies with ≤ 1-year or > 2-year follow-ups. However, the difference was non-significant in studies with > 1-year but ≤ 2-year follow-up (MD: -0.649 mmHg; 95% CI: -5.157 to 3.858; p=0.15). The heterogeneity between studies with more than 2 years of follow-up was low (I2 = 11.4%), while the observed heterogeneities were high in all other groups.
Additionally, only Roux-en-Y gastric bypass surgery significantly reduced SBP (MD: -6.805 mmHg; 95% CI: -11.348 to -2.261; p<0.01), while other types of bariatric surgery did not show significant differences compared to non-surgical interventions.
A meta-analysis comparing the reduction in diastolic blood pressure between surgical and non-surgical interventions was performed with 25 RCTs. High between-study heterogeneity (I2 = 73.4%) was observed. The reduction in DBP was significantly greater in the surgical groups compared to the non-surgical groups (MD: -3.040 mmHg; 95% CI: -4.765 to -1.314; p=.001). Subgroup analyses showed significant differences in DBP changes between the surgical and non-surgical arms in studies with ≤ 1-year or > 2-year follow-ups. Similar to the SBP analysis, RYGB surgery was significantly better at reducing DBP compared to non-surgical interventions (MD: -3.955 mmHg; 95% CI: -6.504 to -1.406; p<0.01).
Subgroup analyses based on follow-up duration and type of surgery showed that bariatric surgery was significantly superior to non-surgical treatments in reducing fasting blood sugar (FBS) in all groups, except for those with > 1-year but ≤ 2-year follow-up time and the DJBL/BPD surgery group. The between-study heterogeneity remained high in all subgroups except the subgroup of > 2 years follow-up (I2 = 0.0%).
The mean changes in HbA1c were reported in 24 RCTs. Patients who underwent bariatric surgery had a significantly greater reduction in HbA1c compared to those treated non-surgically (MD: -1.108%; 95% CI: -1.414 to -0.802; p<0.001). Although the DJBL/BPD surgery group did not show a significant difference from non-surgical treatments, the superiority of surgical intervention remained significant for all other types of surgery.
Twenty-five RCTs were included in a meta-analysis to assess mean triglyceride level changes between surgical and non-surgical treatments. The pooled results indicated that surgical interventions were more effective in reducing TG levels compared to non-surgical treatments (MD: -39.746 mg/dl; 95% CI: -54.458 to -25.034; p<0.001). Subgroup analysis revealed that only patients in the RYGB and LAGB surgery groups experienced significant reductions in TG levels, while other types of bariatric surgery did not show significant superiority over non-surgical treatments. However, in subgroup analyses based on follow-up duration, all groups demonstrated the superiority of surgical interventions.
Changes in HDL levels were pooled from 25 studies, which also showed high heterogeneity (I² = 73.1%). Individuals in the surgical arms had a greater increase in HDL levels compared to those in the non-surgical arms (MD: 7.387 mg/dl; 95% CI: 5.056 to 9.719; p<0.001). Only the RYGB and LAGB surgery groups showed significant differences in mean HDL changes compared to non-surgical treatments. Additionally, all follow-up duration subgroups indicated significant superiority of surgical interventions.
Twenty studies reporting mean total cholesterol changes for surgical and non-surgical interventions were included. Despite high heterogeneity (I² = 90.8%), the meta-analysis revealed that the mean difference between the two arms was not statistically significant (MD: -8.635 mg/dl; 95% CI: -19.847 to 2.576; p=0.12). Subgroup analyses based on follow-up duration or type of surgery also showed non-significant differences in MD between surgical and non-surgical treatments. The heterogeneity was moderate in subgroups of studies with > 1-year but ≤ 2-year and more than 2 years follow-up duration (I2 = 47.8% and 44.1%, respectively).
“The extensive sample size of this study provides robust and generalisable evidence, offering valuable insights for patient care teams,” the authors concluded. “These findings affirm the critical role of bariatric surgery in managing obesity and improving related health conditions such as hypertension, diabetes, and dyslipidaemia, supporting its use as an effective treatment option.”
The findings were reported in the paper, The role of bariatric surgery in hypertension control: a systematic review and meta-analysis with extended benefits on metabolic factors’, published in BMC Cardiovascular Disorders. To access this paper, please click here