Changes in renal risk factors versus renal function outcome during follow-up in a population-based cohort study

Background. Chronic kidney disease is a growing public health problem worldwide. Previous studies have identified several predictors for renal function decline. However, these studies used a single measurement of these risk factors. Therefore, the aim of this study was to investigate whether besides the baseline values of these risk factors, changes in risk factors are associated with subsequent rate of renal function loss. Methods. Five thousand, six hundred and fifty-one participants in the Prevention of Renal and Vascular ENd-stage Disease (PREVEND) Study, a prospective, community-based cohort study, completed three screening visits during a follow-up of 6.5 years for detailed clinical and biochemical measurements. Change in renal function between the second and third screening rounds was chosen as the study parameter of interest. Changes in risk factors between the first and second screening rounds were incorporated as potential predictors for renal function loss in multivariable linear regression analyses. Based on the results of a previous study, gender-specific analyses were performed. Results. In males, an increase in urinary albumin excretion (UAE), systolic blood pressure (SBP) and cholesterol was associated with a subsequent higher rate of renal function loss, whereas in females, increases in glucose levels were associated with an increase in renal function. For males, the analyses showed that both the baseline values and the change in UAE and cholesterol were significant predictors for increased rate of renal function loss during subsequent follow-up. With respect to SBP, when taking also the change in this variable into account, the baseline value was no longer a significant predictor for renal function loss. Conclusions. The results of the present study show the value of screening programs including repeated measurements of risk factors. Furthermore, these data indicate that, besides baseline values of risk factors, the changes over time in these factors should also be taken into account when developing 'Renal Risk Scores' to identify subjects in the general population who are at risk for accelerated renal function deterioration.