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

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. 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. Integrating essence of "time" for blood pressure control in nephrology careKidney InternationalVol. 105Issue 4PreviewControlling blood pressure (BP) is essential in the management of patients with chronic kidney disease. Reflecting the intrinsic variability of BP, several parameters of BP over time have been shown to predict adverse outcomes. Systolic BP time in target range has been recently proposed as a new promising parameter. Park et al. confirmed its prognostic value in patients with chronic kidney disease. We review the potential clinical usefulness and challenges of this parameter in nephrology care. Full-Text PDF in this issueKidney InternationalVol. 105Issue 4PreviewTo address the question of whether the kidney biopsies of patients with IgA nephropathy (IgAN) could differentiate those who were destined to do well from those who were destined to develop progressive loss of kidney function, Rivedal et al. investigated glomerular transcript expression from the biopsies of patients with IgAN followed for about 20 years and who remained stable or progressed. RNA-sequencing revealed over 1200 differentially expressed genes. Given the interest in complement-targeted therapeutics for IgAN, the investigators looked at complement transcript expression and found that several complement activation transcripts were overexpressed in progressors, while the complement regulator, complement receptor 1 (CR1) was overexpressed in nonprogressors. Full-Text PDF