Findings from the KNOW-CKD Study indicate that higher systolic blood pressure time in target range is associated with a lower risk of chronic kidney disease progression

Abstract

Time-in-target range (TTR) of systolic blood pressure (SBP) is determined by the proportion of time during which SBP remains within a defined optimal range. TTR has emerged as a useful metric for assessing SBP control over time. However, it is uncertain if SBP-TTR can predict the progression of chronic kidney disease (CKD). Here, we investigated the association between SBP-TTR during the first year of enrollment and CKD progression among 1758 participants from the KNOW-CKD (KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease). Baseline median estimated glomerular filtration rate (eGFR) was 51.7 ml/min per 1.73 m2. Participants were categorized into four SBP-TTR groups (0%, 1–50%, 51–99%, and 100%). The primary outcome was CKD progression defined as 50% or more decline in eGFR from baseline measurement or the initiation of kidney replacement therapy. During the follow-up period (9212 person-years over a median 5.4 years), the composite outcome occurred in 710 participants. In the multivariate cause-specific hazard model, a one-standard deviation increase in SBP-TTR was associated with an 11% lower risk of the composite outcome with hazard ratio, 0.89 (95% confidence interval, 0.82–0.97). Additionally, compared to patients with SBP-TTR 0%, the respective hazard ratios for those with SBP-TTR 1–50%, 51–99%, and 100% were 0.85 (0.68–1.07), 0.76 (0.60–0.96), and 0.72 (0.55–0.94), and the respective corresponding slopes of eGFR decline were –3.17 (–3.66 to –2.69), –3.02 (–3.35 to –2.68), –2.62 (–2.89 to – 2.36), and –2.33 (–2.62 to –2.04) ml/min/1.73 m2 . Thus, higher SBP-TTR was associated with a decreased risk of CKD progression in patients with CKD.