Factors Associated With Discordant Blood Pressure Measures among Very Old Adults: Results From the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND: Home blood pressure (BP) monitoring (HBPM) is increasingly used as an alternative to office BP. However, factors influencing agreement between office and home BP among very old adults remain unclear. METHODS: During ARIC (Atherosclerosis Risk in Communities) visit 10, participants underwent 3 automated office BP (AOBP) measurements using an Omron HEM-907XL and performed HBPM twice daily for 8 days using an Omron BP7450. Discordance was defined as a systolic BP difference of ±10 mm Hg between mean AOBP and HBPM. Multivariable regression models evaluated demographic, anthropometric, and clinical factors associated with discordance. RESULTS: Among 792 participants (58% female; mean age, 84±3.7 years), mean systolic BP was 130.6 mm Hg (AOBP) and 129.6 mm Hg (HBPM). Despite a minimal average difference (1.0±15.7 mm Hg), 49% had ≥10 mm Hg systolic BP discordance. Higher AOBP was associated with greater discordance. Compared with females, males had lower AOBP relative to HBPM (-4.69 mm Hg [95% CI, -6.86 to -2.51]). Smaller arm circumference was associated with higher discordance (β=14.4 mm Hg [95% CI, 4.78-24.04]). Frail adults had lower AOBP relative to HBPM (β, -5.1 mm Hg [95% CI, -11.0 to 0.9]). Baseline AOBP systolic BP ≥140 mm Hg strongly predicted discordance ≥+10 mm Hg (odds ratio, 8.27 [95% CI, 5.52-12.40]). Participants aged 91 to 100 years had lower AOBP than those aged 78 to 80 years (β, -5.0 mm Hg [95% CI, -10.06 to 0.001]). CONCLUSIONS: Among very old adults, substantial BP discordance between AOBP and HBPM was common and influenced by higher BP, age, male sex, arm circumference, and frailty.