Document Type
Article
Department
Internal Medicine (East Africa); Population Health (East Africa)
Abstract
Introduction: hypertension represents the primary modifiable risk factor for cardiovascular disease and poses a public health challenge in sub-Saharan regions, with Kenya experiencing particularly low detection and control rates. Traditional office-based blood pressure measurements often fail to detect key phenotypes, such as white-coat and masked hypertension. Ambulatory Blood Pressure Monitoring (ABPM) offers a comprehensive 24-hour profile that excludes white-coat hypertension and allows for the evaluation of circadian patterns, including nocturnal hypertension and non-dipping status, both of which are recognized as high-risk phenotypes strongly linked to adverse cardiovascular events. This study evaluated ABPM data from Aga Khan University Hospital, Nairobi (AKUHN), to characterize these high-risk phenotypes and identify associated factors.
Methods: we performed a retrospective cross-sectional analysis at Aga Khan University Hospital in Nairobi, spanning from January 2022 to June 2024. Adults (≥18 years) referred for ABPM for diagnostic clarification were included, excluding those with treated hypertension. Data on demographics, cardiovascular risk factors, and ABPM parameters (24-hour, daytime, nighttime pressures, and dipping status) were collected. Hypertension and circadian patterns were classified according to the 2017 AHA/ACC criteria. Results were summarized as frequencies, proportions, and means. Group comparisons used chi-squared/Fisher´s exact tests for categorical and student´s t-test for continuous variables. Multivariate logistic regression identified predictors of adverse circadian patterns (non-dipping and reverse dipping). Statistical significance was set at p< 0.05.
Results: a total of 180 patients were included in the analysis, with a median age of 47 years (IQR 38-62); 124 (68.9%) were aged >40 years. Males accounted for 95 (52.8%) of the cohort, and 78 (46.2%) were diabetic. The mean office systolic and diastolic pressures were 143.1 ± 20.1 mmHg and 82.4 ± 12.5 mmHg, respectively. Using ABPM, hypertension was confirmed in 171 (95.0%) patients. Nocturnal hypertension was more prevalent than daytime hypertension (152, 84.4% vs. 128, 71.1%). Circadian patterns showed that 139 (77.2%) exhibited a non-dipping or reverse-dipping status. Reverse dippers had the highest mean nocturnal systolic/diastolic pressures (142.3 ± 15.5 / 83.7 ± 11.1 mmHg). No factors demonstrated a statistically significant (P-value < .05) association with adverse circadian rhythm patterns. However, individuals with higher BMI and those with diabetes showed a trend toward increased odds of adverse circadian rhythm.
Conclusion: this study revealed a high prevalence of hypertension, particularly nocturnal hypertension, with most patients showing non-dipping patterns linked to greater cardiovascular risk. Although no factors were significantly associated with adverse circadian rhythms, patients with higher BMI and diabetes demonstrated increased odds, highlighting the high-risk phenotypes.
Publication (Name of Journal)
Pan African Medical Journal
DOI
https://www.panafrican-med-journal.com/content/article/54/60/full
Recommended Citation
Kassam, N.,
Ngunga, M.,
Orwa, J.,
Bhojani, A.,
Varwani, M.,
Salim, S.,
Oketch, Y.,
Surani, S.,
Ochola, A.,
Karau, B.,
Mohamed, J.,
Amendezo, E.
(2026). Ambulatory blood pressure monitoring phenotypes and circadian blood pressure patterns among adults referred for diagnostic evaluation at Aga Khan University Hospital, Nairobi, Kenya: A retrospective cross-sectional study. Pan African Medical Journal, 54(60), 1-14.
Available at:
https://ecommons.aku.edu/eastafrica_fhs_mc_intern_med/622
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.