Dissociation Between Long-term Weight Loss Intervention and Blood Pressure: an 18-month Randomized Controlled Trial

Background: Obesity is associated with elevated blood pressure (BP). In patients with obesity and hypertension, weight loss lowers BP, but the long-term effect of weight loss on BP is less clear. Objective: We aimed to assess the effect of long-term weight loss intervention on BP in normotensive and hypertensive subjects. Design: Randomized controlled trial. Participants: Two hundred seventy-eight subjects (mean age 47.9 ± 9.3 years, 89% male, 56% hypertensive) with abdominal obesity or elevated serum triglycerides and low high-density lipoprotein cholesterol were recruited. Intervention: Eighteen-month weight loss intervention. Main Measures: Body weight and BP were measured at baseline, after 6 and 18 months. Results: After 6 months of intervention, in the weight loss phase, body mass index (BMI) decreased by an average of −2.2±1.5 kg/m² (p<0.001) and both diastolic BP (DBP) and systolic BP (SBP) decreased by −2.1±8.8 mmHg and −2.3±12.9 mmHg, respectively (p<0.01 for both). The change in BMI was similar in normotensive and hypertensive subjects (−2.0±1.6 and −2.3±1.5, p = 0.246). However, DBP and SBP decreased significantly (−5.2±7.1 mmHg and −6.2±12.5 mmHg, respectively, p<0.001 for both) in hypertensive subjects, and increased in normotensive subjects (1.8±9.3 mmHg, p = 0.041 and 2.7±11.7 mmHg, p = 0.017, respectively). After 18 months, in the weight maintenance phase, BMI slightly increased (0.9±1.3 kg/m², p<0.001) but remained significantly lower than at baseline (p<0.0001). Unlike BMI, DBP and SBP increased significantly in hypertensive subjects (p<0.001) and returned almost to baseline levels. Conclusion: Weight-loss intervention reduced BP in hypertensive patients, but this was not maintained in the long run. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT01530724.