Abstract P319: Effects of Environment and Noise on Blood Pressure Readings: The (Decibel(s)) Trial

Abstract

Background: While guidelines emphasize quiet settings for blood pressure (BP) measurement, large-scale hypertension screening is often conducted in noisy, public spaces (e.g., health fairs). However, the influence of noise and environment on BP readings is unknown. Methods: We conducted a randomized crossover trial of community dwelling adults in Baltimore, MD to determine the BP effect of noise and public environment. Participants were randomly assigned to the order of triplicate BPs in 3 spaces: private quiet office (private quiet 1 [reference]); noisy public space (public loud); noisy public space + earplugs (public quiet). To account for intrinsic BP variability, all participants underwent a 4th set of BP measurements in a private quiet office (private quiet 2 ). Between each set of triplicate BPs with a WelchAllyn ProB 2000 device and appropriately sized cuff, participants walked for ≥2 minutes, rested for 5 minutes, and had arm/back/feet supported. We conducted difference in difference analysis, overall and stratified by baseline SBP (≥ vs. < 130mmHg) and age (≥ vs. <60yrs). Results: N=108, mean age 56 (SD 17) yrs (55% ≥60 years), 91% Black race, and 44% female. 45% had SBP≥130mmHg. Mean private quiet 1 and private quiet 2 BP was 129/74 and 127/74 mmHg (SBPΔ -1.6 (SD 7.1)/DBPΔ -0.2 (SD 4.0)). The average noise level in public loud was 74 db and in private quiet was 37 db. Public loud and public quiet BPs were slightly different than private quiet 1 BPs, with difference in differences minimal (Table): [Public loud: SBPΔ 0.97 mmHg (95%CI: -0.61, 2.55)/DBPΔ 1.86 mmHg (95%CI: 0.94, 2.78); Public quiet: SBPΔ 1.72mmHg (95%CI: 0.05, 3.39)/DBPΔ 1.66 mmHg (95%CI: 0.79, 2.54)]. The patterns were generally consistent across subgroups by SBP and age. Conclusion: BP readings in noisy public spaces resulted in small overestimation of BP compared to readings in a quiet private office, but the difference was minimal. Large-scale hypertension screening programs in public loud places may be an acceptable option, especially in low resource settings.