BP and Kidney Disease Progression in Advanced CKD Findings from the Chronic Renal Insufficiency Cohort and KoreaN Cohort Study for Outcome in Patients with CKD Studies

Abstract

Key Points:

Higher BP was associated with a higher risk of kidney disease progression in patients with CKD G3b–G5.

A stronger association observed with time-updated BP emphasizes the importance of consistently maintaining optimal BP over time.

Further validation through well-designed clinical trials is warranted to determine optimal BP in patients with CKD.

Background: BP control is important in the management of CKD. However, in patients with advanced CKD, the benefits of BP control in delaying the progression of CKD remain uncertain.

Methods: We analyzed 2939 participants with CKD G3b–G5 (eGFR <45 ml/min per 1.73 m2) without KRT from the Chronic Renal Insufficiency Cohort study and the KoreaN Cohort Study for Outcome in Patients with CKD (phase 1). The main predictors were baseline and time-updated systolic BP (SBP) and diastolic BP. The primary outcome was a composite kidney outcome of ≥50% decline in eGFR from baseline measurement or the initiation of KRT. In the analyses, multivariate cause-specific hazards models and marginal structural models were fitted for baseline and time-updated BPs, respectively.

Results: During 17755 person-years of follow-up (median, 4.7 years), the composite outcome occurred in 1627 (55%) participants. Compared with baseline SBP <120 mm Hg, the hazard ratios (95% confidence intervals) for 120–129, 130–139, and ≥140 mm Hg were 1.33 (1.15 to 1.54), 1.48 (1.27 to 1.72), and 1.82 (1.58 to 2.10), respectively. This association was more evident in analysis with time-updated SBP, where the corresponding hazard ratios (95% confidence intervals) were 1.29 (1.09 to 1.54), 1.75 (1.46 to 2.10), and 2.79 (2.36 to 3.29), respectively. Furthermore, the slopes of eGFR decline were –1.20 (–1.36 to –1.04), –1.77 (–1.97 to –1.57), –2.11 (–2.35 to –1.88), and –2.48 (–2.70 to –2.27) ml/min per 1.73 m2 per year for respective baseline SBP categories. Additional analyses with diastolic BP also showed similar results.

Conclusions: In patients with advanced CKD, higher BP levels were associated with a higher risk of CKD progression.