Visit-to-visit blood pressure variability and risk of chronic kidney disease: A systematic review and meta-analyses.

OBJECTIVE Previous studies have shown that visit-to-visit blood pressure variability (BPV) is associated with chronic kidney disease (CKD). However, the results have not been consistent among studies. This systematic review and meta-analysis was conducted to comprehensively assess the association between visit-to-visit BPV and the risk of CKD. METHODS Medline, Embase, and the Cochrane Library were searched from the date of inception through 1 August 2019 using the terms "blood pressure variability," "chronic kidney disease," "nephropathy," and other comparable terms. The primary outcome was the development of CKD. Two reviewers extracted the data independently. Meta-analysis was performed using a random effects model. RESULTS Fourteen studies were included in the systematic review and meta-analysis. The risk of CKD was significantly greater in patients with high baseline systolic blood pressure variability (SBPV) than in patients with low baseline SBPV: the standard deviation (SD) showed relative risk (RR) of 1.69 and 95% CI of 1.38-2.08, the coefficient of variation (CV) showed RR of 1.23 and 95% CI of 1.12-1.36, and variance independent of mean (VIM) showed RR of 1.40 and 95% CI of 1.15-1.71. RRs for each unit increase in visit-to-visit SBPV and risk of CKD were 1.05 (95% CI: 1.03-1.07) for SD, 1.06 (95% CI: 1.03-1.09) for CV, and 1.1 (95% CI: 0.96-1.25) for VIM. Diastolic BPV was similarly predictive of CKD based on SD and CV. CONCLUSIONS Increased visit-to-visit BPV might be an independent risk factor for CKD. However, significant heterogeneity was present; thus, future prospective studies are needed to confirm our findings. Our results indicate that treatment of hypertension should control blood pressure levels and prevent abnormal fluctuations in blood pressure to reduce the risk of CKD.