Abstract P154: Results From A Randomized Trial Of Different Rest Times Before Initiating BP Measurements

Abstract

Background: BP measurement guidelines recommend ≥5 min of rest before initiation of readings; this wait time is challenging to implement, especially in resource-constrained settings. Objective: Compare the effects of resting 0 or 2 min vs. 5 min on BP. Design and methods: RCT of community-dwelling adults, 18-80yrs. Participants had 4 sets of BP measurements (Omron HEM 970XL). In a cross-over design, the order of rest for the 1 st 3 sets [0min, 2min, 5min 1 ] was random. The 4 th set was always a 2nd 5min rest period (5min 2 ) to estimate repeatability. Mean BP for each rest period, mean absolute difference between each participant’s mean BP after 5min 1 and the other rest periods were determined. To determine if resting 0min and/or 2min was non-inferior to 5min 1 , we calculated the difference of differences, with ≤ ±2 mmHg considered non-inferior. Analyses were for the population overall and stratified by SBP ≥ vs. < 140mmHg. Results: N=113, mean age 55yrs, 36% male (n=41), 74% AA (n=84), 28% SBP > 140mmHg (n=32). Overall, mean 5min 1 BP was 128/75 and 5min 2 BP was 127/76 (p=NS), similar to mean BP at 2min and 0min (127/74 for both). The absolute difference of differences between 2min and 5min 1 SBP for the population overall was > ±2 mmHg, but for those with SBP <140, resting 2min and 0min BP was ≤ ±2 mmHg (Table). Conclusion: In this RCT, mean differences in BP by rest period were small. BPs obtained after shorter rest periods were non-inferior than those obtained after 5min when SBP <140. This suggests shorter rest times, even 0 min, may be reasonable for screening when the initial SBP is <140. These findings could improve the efficiency of hypertension screening, especially in resource-constrained settings.