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.
Willkens M, Lucinde R, et al. • Journal of clinical hypertension (Greenwich, Conn.) • 2026
ABPM and uAOBP demonstrated high short-term reproducibility, with ABPM showing greater stability for hypertension classification, and reproducibility did not differ by HIV status, supporting the use of both approaches in sub-Saharan Africa.
Key Findings
Results
The mean difference in systolic blood pressure between enrollment and 1-month follow-up was statistically significant for uAOBP but not for 24-hour ABPM.
Mean systolic BP difference for uAOBP was -1.02 mmHg (95% CI -1.76, -0.27), which was statistically significant.
Mean systolic BP difference for 24-hour ABPM was -0.46 mmHg (95% CI -1.02, 0.10), which was not statistically significant.
Similar patterns were observed for diastolic blood pressure across both measurement methods.
Measurements were taken at enrollment and approximately 1 month later in the Mwanza HIV&CVD cohort study.
Results
Bland-Altman plots showed narrower limits of agreement for ABPM compared to uAOBP, indicating greater measurement stability for ABPM.
Bland-Altman plots were used to visualize mean differences and limits of agreement between the two timepoints.
Narrower limits of agreement for ABPM suggest less variability in repeated measurements compared to uAOBP.
This finding indicates ABPM provides more consistent blood pressure readings over the short term.
Results
ABPM showed better reproducibility of hypertension classification than uAOBP as measured by Cohen's kappa statistics.
Kappa statistic for uAOBP hypertension classification was 0.45 (95% CI 0.33, 0.56).
Kappa statistic for 24-hour ABPM hypertension classification was 0.56 (95% CI 0.50, 0.62).
A higher kappa for ABPM indicates greater agreement between the two timepoints in classifying individuals as hypertensive or not.
Differences by HIV status were evaluated using large-sample variance methods.
Results
Regression dilution ratios indicated attenuation of blood pressure measurements upon repeat testing for both uAOBP and ABPM.
Regression dilution ratios for uAOBP were 0.77 for systolic and 0.82 for diastolic blood pressure.
Regression dilution ratios for ABPM were 0.73 for systolic and 0.77 for diastolic blood pressure.
Values less than 1.0 indicate regression to the mean, meaning extreme readings at baseline tended to be less extreme at follow-up.
These ratios reflect short-term variability and potential measurement error inherent in both methods.
Results
Reproducibility of both blood pressure measurement methods did not differ by HIV status.
Of 999 participants enrolled, 750 had valid ABPM measurements at both timepoints: 384 people with HIV (PWH) and 366 people without HIV (PWoH).
Differences in reproducibility by HIV status were evaluated using large-sample variance testing.
No statistically significant difference in reproducibility was found between PWH and PWoH for either measurement method.
This finding supports the use of both uAOBP and ABPM in populations with high HIV prevalence such as those in sub-Saharan Africa.
Background
The study was conducted in Tanzania as part of the Mwanza HIV&CVD cohort study, addressing a gap in blood pressure measurement research in sub-Saharan Africa.
Sub-Saharan Africa bears a high burden of both hypertension and HIV, yet blood pressure measurement often relies on single-day, conventional office readings prone to measurement error.
999 participants were enrolled in total, with 750 providing valid ABPM data at both timepoints.
The study assessed short-term repeatability using measurements from enrollment and 1 month later.
Both uAOBP and ABPM were evaluated as alternatives to conventional office blood pressure measurement.
What This Means
This research studied how consistently two types of blood pressure measurement methods — unattended automated office blood pressure (uAOBP) and ambulatory blood pressure monitoring (ABPM) — produce the same results when repeated about a month apart in Tanzania. The study included nearly 1,000 adults, about half of whom were living with HIV. This is important because sub-Saharan Africa has very high rates of both high blood pressure and HIV, but blood pressure is often measured using single, traditional office readings that can be unreliable.
The study found that both methods were reasonably consistent over the short term, but ABPM performed somewhat better. When classifying whether someone had high blood pressure, ABPM agreed with itself across the two time points more often than uAOBP did. Both methods showed some tendency for extreme readings at the first visit to be less extreme at the second visit — a phenomenon called 'regression to the mean' — which is a known source of measurement error in blood pressure studies. Importantly, neither method was more or less reliable in people living with HIV compared to those without HIV.
This research suggests that both uAOBP and ABPM are viable options for measuring blood pressure in sub-Saharan African populations, including those with HIV. The finding that HIV status did not affect measurement reliability is reassuring for healthcare programs serving populations with high HIV prevalence. ABPM's slightly better performance in consistently classifying hypertension may make it preferable where resources allow, but both approaches appear suitable for use in this setting.
Willkens M, Lucinde R, Cichowitz C, Etyang A, Kisigo G, Ruselu G, et al.. (2026). 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.. Journal of clinical hypertension (Greenwich, Conn.). https://doi.org/10.1111/jch.70373