Prevalence and Determinants of Ambulatory Hypertension Phenotypes in a Semi-Urban Nigerian Population

Background: Ambulatory blood pressure monitoring (ABPM) provides more accurate diagnostic and prognostic information than office blood pressure (BP), yet it remains underutilised in sub-Saharan Africa. As a result, the actual distribution of hypertension phenotypes identified through ABPM is poorly understood. This study aimed to determine the prevalence and determinants of hypertension phenotypes using 24-hour ABPM in a semi-urban Nigerian population. Methods: This community-based cross-sectional study involved 348 adults in Ido-Ekiti, Nigeria. Sociodemographic and clinical data were collected using the WHO STEPS protocol. Office BP was measured with standardised methods, and 24-hour ABPM (CONTEC ABPM60®) provided daytime, night-time, and 24-hour BP readings. Hypertension phenotypes were defined using standard thresholds. Multivariable logistic regression identified predictors. Results: Sustained hypertension occurred in 31.8%, ambulatory hypertension in 32.4%, nocturnal hypertension in 56.8%, isolated nocturnal hypertension in 26.1%, and morning hypertension in 40.6%. White-coat hypertension was found in 15.3%, masked hypertension in 4.3%, and true normotension in 34.7%. Females had higher rates of morning (46.4% vs 33.3%; p = 0.013), ambulatory (38.3% vs 25.0%; p = 0.008), and masked hypertension (7.7% vs 0%; p = 0.001). Sustained, nocturnal, and morning hypertension increased markedly with age (p < 0.001), while true normotension declined. Higher income (₦301,000–₦500,000) independently predicted sustained (OR 12.12), nocturnal (OR 31.3), and morning hypertension (OR 20.8). Secondary education was protective. True normotension was more likely among adults aged 40–59 years and those with higher incomes. Conclusion: ABPM revealed a high burden of sustained, nocturnal, and morning hypertension undetectable by office BP alone. Strong socioeconomic and age gradients support wider ABPM integration and phenotype-specific management in sub-Saharan Africa.