Association of Blood Pressure with Cardiovascular Outcome and Mortality: Results from the KNOW-CKD Study.

BACKGROUND Optimal BP control is a major therapeutic strategy to reduce adverse cardiovascular events and mortality in patients with CKD. We studied the association of BP with adverse cardiovascular outcome and all-cause death in patients with CKD. METHODS Among 2,238 participants from the KoreaN cohort study for Outcome in patients With CKD, 2,226 patients with baseline BP measurements were enrolled. Main predictor was SBP categorized by 5 levels: <110, 110-119, 120-129, 130-139, and ≥140 mmHg. Primary endpoint was a composite outcome of all-cause death or incident cardiovascular events. We primarily used marginal structural models using averaged and the most recent time-updated SBPs. RESULTS During a median follow-up of 10233.79 person-years (median 4.60 years), the primary composite outcome occurred in 240 (10.8%) participants, with a corresponding incidence rate of 23.5 (95% CI, 20.7-26.6) per 1,000 patient-years. Marginal structural models with averaged SBP showed a U-shaped relationship with the primary outcome. Compared to time-updated SBP of 110-119 mmHg, hazard ratios (95% CI) for <110, 120-129, 130-139, and ≥140 mmHg were 2.47 (1.48-4.11), 1.29 (0.80-2.08), 2.15 (1.26-3.69), and 2.19 (1.19-4.01), respectively. Marginal structural models with the most recent SBP also showed similar findings. CONCLUSIONS In Korean patients with CKD, there was a U-shaped association of SBP with the risk of adverse clinical outcome. Our findings highlight the importance of BP control and suggest a potential hazard of SBP <110 mmHg.