The relation between the evolution in blood pressure and the evoluation in renal function over time

Abstract

The aim of this master thesis is to extend the methodology and to confirm the results obtained in the previously published paper in which the authors explored the relationship between evolution of kidney function over time and blood pressure. Specifically, it is of interest to expand the statistical methodology presented in the previous analysis by Vaes et al. (2015) and to incorporate the longitudinal structure of the data to make inference about how blood pressure measurements influence the kidney function expressed as estimated glomerular filtration rate (eGFR). As to the methods used in this analysis, linear mixed models for longitudinal data and generalized estimating equations (GEE) were used to answer the research questions. A positive effect of systolic and diastolic blood pressure on the baseline eGFR values was identified. Moreover, it was concluded that the effect of BP changes as time from baseline elapses and the overall eGFR level decreases as time passes. Patients characteristics such as gender and age above 70 years and above 80 years had a significant negative effect on the eGFR value, also a positive relationship between cardiovascular mediaction and outcome was confirmed. The probability of annual rapid kidney function decline was affected by patient baseline characteristics and by baseline eGFR value with higher values contributing surprisingly to higher odds for rapid decline.