The effects of weight loss and salt reduction on visit-to-visit blood pressure variability: results from a multicenter randomized controlled trial

Abstract

Objectives: As evidence suggests visit-to-visit variability (VVV) of blood pressure (BP) is associated with cardiovascular events and mortality, there is increasing interest in identifying interventions that reduce VVV of BP. We investigated the effects of weight loss and sodium reduction, alone or in combination, on VVV of BP in participants enrolled in phase II of the Trials of Hypertension Prevention.

Methods: BP readings were taken at 6-month intervals for 36 months in 1820 participants with high-normal DBP who were randomized to weight loss, sodium reduction, combination (weight loss and sodium reduction), or usual care groups. VVV of BP was defined as the SD of BP across six follow-up visits.

Results: VVV of SBP was not significantly different between participants randomized to the weight loss (7.2 ± 3.1 mmHg), sodium reduction (7.1 ± 3.0 mmHg), or combined (6.9 ± 2.9 mmHg) intervention groups vs. the usual care group (6.9 ± 2.9 mmHg). In a fully adjusted model, no difference (0.0 ± 0.2 mmHg) in VVV of SBP was present between individuals who successfully maintained their weight loss vs. individuals who did not lose weight during follow-up (P = 0.93). Also, those who maintained a reduced sodium intake throughout follow-up did not have lower VVV of SBP compared to those who did not reduce their sodium intake (0.1 ± 0.3 mmHg; P = 0.77). Results were similar for VVV of DBP.

Conclusions: These findings suggest that weight loss and sodium reduction may not be effective interventions for lowering VVV of BP in individuals with high-normal DBP.

Figure 1

Baseline and follow-up visits at which blood pressure (BP) measurements were obtained in TOHP II, and the estimation of visit-to-visit variability (VVV) in the current study. Upper panel shows when BP measurements (●) were obtained in TOHP II. The grey boxes in the middle panel show the visits used to calculate VVV of BP using follow-up visits performed every 6 months (VVV_FU). The grey boxes in the lower panel show the visits used to calculate VVV of BP using visits performed at shorter intervals at baseline (VVV_baseline), 18-months (VVV_18mo) and 36-months (VVV_36mo).