Joint modeling of hypertension measurements and time-to-onset of preeclampsia among pregnant women attending antenatal care service at Arerti Primary Hospital, North Shoa, Ethiopia

Abstract

Preeclampsia is a hypertensive disorder of pregnancy that affects 2–8% of pregnant women. The purpose of this study was to identify factors associated with hypertension measurements and time-to-onset of preeclampsia among pregnant women attending antenatal care service at Arerti Primary Hospital. Separate and joint methods of longitudinal data analysis and survival data analysis were fitted to answer the research objectives. A retrospective longitudinal study design was employed on a total of 201 pregnant women attending the antenatal clinic of Arerti Primary Hospital between September 2018 and June 2019. To analyze our data we employed descriptive method, linear mixed effect model, Cox-PH model and joint models for longitudinal and survival outcomes. Relevant demographic and clinical covariates were included in sub models. This study revealed that baseline age, visiting times, weight, diabetes, history of Preeclampsia and parity had significantly associated with mean change in the blood pressure measurements. From the Cox model result, age, weight, history of Preeclampsia and marital status were associated with a significant hazard of developing preeclampsia. The uni-variate joint models reveal that each longitudinal blood pressure measurements are significantly associated with hazard of developing preeclampsia. Form the bivariate joint model; only diastolic blood pressure is significantly associated with risk of developing Preeclampsia. As the result obtained in this study, we summarized that, age, weight, history of Preeclampsia and marital status had a significant effect on time to developing preeclampsia. Furthermore, due to significance of association between the longitudinal blood pressure measurements and time to onset of preeclampsia, joint model analysis was suggested as it incorporates all information simultaneously and provides valid and efficient inferences over separate models analysis.

Keywords

• joint model
• diastolic blood pressure
• systolic blood pressure
• time to onset of preeclampsia