Undiagnosed hypertension and its determinants among hypertensive patients in rural districts of northwest Ethiopia: a mediation analysis

BACKGROUND: Early detection of hypertension is associated with improved blood pressure control and a reduced risk of cardiovascular diseases. However, in rural areas of Ethiopia, evidence is scarce where access to healthcare services is low. This study aimed to estimate the proportion of undiagnosed hypertension and identify its determinants and mediators among patients with hypertension in rural northwest Ethiopia. METHODS: A community-based cross-sectional study was conducted from September to November 2020. A three-stage sampling technique was used to select a total of 2436 study participants. Blood pressure was measured using an aneroid sphygmomanometer two times, 30 min apart. A validated tool was used to assess participants’ beliefs and knowledge of hypertension. The proportion, determinants, and mediators of undiagnosed hypertension were determined among patients with hypertension. The regression-based approach used to calculate the direct and indirect effects of determinants of undiagnosed hypertension. Joint significance testing was used to determine the significance of the indirect effect. RESULTS: The proportion of undiagnosed hypertension was 84.0% (95% CI: 81.4–86.7%). Participants aged 25–34 years (AOR = 6.03; 95% CI: 2.11, 17.29), who drank alcohol (AOR = 2.40; 95% CI: 1.37, 4.20), were overweight (AOR = 0.41; 95% CI: 0.18, 0.98), had a family history of hypertension (AOR = 0.32; 95% CI: 0.20, 0.53), and had comorbidities (AOR = 0.28; 95% CI: 0.15, 0.54) were significantly associated with undiagnosed hypertension. The mediation analysis revealed that hypertension health information mediated 64.1% and 68.2% of the effect of family history of hypertension and comorbidities on undiagnosed hypertension, respectively. Perceived susceptibility to hypertensive disease mediated 33.3% of the total effect of age on undiagnosed hypertension. Health facility visits also mediated the effect of alcohol drinking (14.2%) and comorbidities (12.3%) on undiagnosed hypertension. CONCLUSION: A higher proportion of hypertensive patients remain undiagnosed. Being young, drinking alcohol, being overweight, having a family history of hypertension, and having comorbidities were significant factors. Hypertension health information, knowledge of hypertensive symptoms, and perceived susceptibility to hypertension were identified as important mediators. Public health interventions aimed at providing adequate hypertension health information, particularly to young adults and drinkers, could improve knowledge and perceived susceptibility to hypertensive disease and reduce the burden of undiagnosed hypertension. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12913-023-09212-1.