Joint Modeling of Blood Pressure Measurements and Survival Time to Cardiovascular Disease Complication among Hypertension Patients Follow-up at DebreTabor Hospital, Ethiopia.

Introduction: Hypertension is also referred to as a silent killer and a leading factor for cardiovascular disease complication in the world today. This study aimed to identify the factors that affect longitudinal outcomes and survival time for cardiovascular disease complications among patients with hypertension.

Methods: A retrospective cohort study was conducted among a randomly selected sample of 178 outpatients with hypertension at the Debre Tabor Specialized Hospital between September 2017 and December 2019. Three different models were used to analyze the data: the bivariate mixed-effects model, Cox proportional hazard model, and bivariate joint model for longitudinal and survival sub-models linked by shared random effects.

Results: Bivariate mixed-effects and Cox proportional hazards survival sub-models were jointly preferred based on the minimum Akaike Information Criterion value. The estimated values of the association parameters were 0.0655 (p = 0.0270) and 0.963 (p = 0.0387), indicating that the association between systolic and diastolic blood pressure with time to event was guaranteed. The joint bivariate mixed-effects model analysis showed that patients with hypertension with a family history of hypertension and clinical stage II hypertension have a high chance of developing cardiovascular disease complications and have high average systolic and diastolic blood pressure compared to their counterparts. Patients with hypertension and diabetes have higher systolic and diastolic blood pressure than their counterparts.

Conclusion: Generally, systolic and diastolic blood pressure stabilized over the follow-up period of treatment, while sex and residence were statistically insignificant to the survival time of cardiovascular disease complication. Health professionals and concerned bodies should therefore focus on patients with comorbidities, older age, and poor adherence to hypertension control and cardiovascular disease complications using technology, such as text messaging, and mobile application to promote cardiovascular health at early stage. It is important to provide early interventions for these groups of people, especially for those with family history.