Long-term Blood Pressure Variability and Kidney Function in Participants of the ASPREE Trial.

Background Whether long-term blood pressure variability (BPV) predicts kidney function decline in generally healthy older adults is unknown. We investigated this association in ASPirin in Reducing Events in the Elderly (ASPREE) trial participants. Methods Between 2010-2014, Australian and US individuals aged ≥70 years ( ≥65 if US minority) were recruited and followed with annual study visits for a median of 4.7 years. Time-to-event analyses and linear mixed effects models were used to examine associations between incident chronic kidney disease (CKD), and trajectories of estimated glomerular filtration rate (eGFR) and log albumin-creatinine ratio (log ACR) with systolic BPV as a continuous measure, and, by tertile of standard deviation (SD) of systolic BP. BPV was estimated using systolic BP measures from baseline through the second annual visit, andkidney outcomes were assessed following this period. Results Incident CKD occurred in 1,829 of 6,759 participants (27.2%), and more commonly in BPV tertiles 2 (27.4%) and 3 (28.3%) than tertile 1 (25.5%); however, the risk was not significantly increased after covariate adjustment (tertile 3 HR=1.02; 95% CI: 0.91-1.14). Analysis of eGFR (n=16,193) and log ACR trajectories (n=15,213) showed individuals in the highest BPV tertile having the lowest eGFR and highest log ACR, cross-sectionally. However, the trajectories of eGFR and log ACR did not differ across BPV tertiles. Conclusions CKD and markers of reduced kidney function occur more commonly in individuals with higher BPV; however, BPV does not influence trajectory of decline in kidney function over time in older adults who are in generally good health.