Ambulatory and Unattended, Automated Office Blood Pressure in People With and Without HIV in Tanzania: A Cohort Study of Repeatability and Regression to the Mean.

Sub-Saharan Africa (sSA) bears a high burden of hypertension and HIV, yet blood pressure measurement often relies on single-day, conventional office readings, prone to measurement error. We assessed the short-term repeatability of unattended, automated office BP (uAOBP) and ambulatory blood pressure monitoring (ABPM), and whether reproducibility differs by HIV status in Tanzania. We analyzed data from the Mwanza HIV&CVD cohort study, using measurements from enrollment and 1-month later. Bland-Altman plots visualized mean differences and limits of agreement. Reproducibility of hypertension classification was calculated using Cohen's kappa, with differences by HIV status evaluated using large-sample variance. Of 999 participants enrolled, 750 (384 people with HIV (PWH) and 366 people without HIV (PWoH)) had valid ABPM measurements at both timepoints. The mean difference in systolic blood pressure was significant for uAOBP (-1.02 mmHg; 95% CI -1.76, -0.27) but not 24 h ABPM (-0.46; -1.02, 0.10), with similar results for diastolic blood pressure. Bland-Altman plots showed narrower limits of agreement for ABPM. Kappa statistics were 0.45 (0.33, 0.56) for uAOBP and 0.56 (0.50, 0.62) for 24 h ABPM. Regression dilution ratios were 0.77 and 0.82 for systolic and diastolic uAOBP and 0.73 and 0.77 for ABPM. Reproducibility did not differ by HIV status. ABPM and uAOBP demonstrated high short-term reproducibility, with ABPM showing greater stability for hypertension classification. Reproducibility did not differ by HIV status, supporting the use of both approaches in sub-Saharan Africa.