Association of Blood Pressure With the Progression of CKD: Findings From KNOW-CKD Study.

Abstract

RATIONALE & OBJECTIVE\nOptimal blood pressure (BP) control is a major therapeutic strategy in the management of chronic kidney disease (CKD). We studied the association of BP with adverse kidney outcomes within a diverse cohort of Koreans with CKD.\n\n\nSTUDY DESIGN\nProspective observational cohort study.\n\n\nSETTING & PARTICIPANTS\n2,044 participants from the KoreaN Cohort Study for Outcomes in patients With CKD (KNOW-CKD).\n\n\nEXPOSURES\nBaseline and time-updated systolic BP (SBP) and diastolic BP (DBP).\n\n\nOUTCOME\nA composite kidney outcome of a ≥50% decline in estimated glomerular filtration rate (eGFR) from the baseline value or the onset of end-stage kidney disease.\n\n\nANALYTICAL APPROACH\nMultivariable cause-specific hazards models and marginal structural models were fit for baseline and time-updated BP, respectively.\n\n\nRESULTS\nDuring 7,472 person-years of follow-up, the primary composite outcome occurred in 473 (23.1%) participants (incidence rate, 63.3 per 1,000 patient-years). Compared with baseline SBP <120 mmHg, the hazard ratios (HRs) (95% confidence interval [CI]) for 120-129, 130-139, and ≥140 mmHg were 1.10 (0.83-1.44), 1.20 (0.93-1.59), and 1.43 (1.07-1.91), respectively. This association was more evident in the model with time-updated SBP for which the corresponding HRs were 1.31 (0.98-1.75), 1.59 (1.16-2.16), and 2.29 (1.69-3.11) respectively. In the analyses with DBP, we observed that time-updated DBP, but not baseline DBP, was significantly associated with CKD progression. Compared to patients with SBP <120 mmHg, patients with higher SBP had steeper slopes of eGFR decline. In the model including both SBP and DBP, only SBP was significantly associated with CKD progression.\n\n\nLIMITATIONS\nObservational design, unmeasured confounders, and use of only office BPs.\n\n\nCONCLUSIONS\nIn patients with CKD, higher SBP and DBP levels were associated with a higher risk of CKD progression. SBP had a greater association with adverse kidney outcomes than DBP.