Effect of blood pressure index on clinical outcomes in patients with heart failure and chronic kidney disease

AIMS: This study aimed to assess the effect of blood pressure (BP) index, in terms of level and variability, on the progression of cardiovascular and renal diseases in patients with both heart failure (HF) and chronic kidney disease (CKD). METHODS AND RESULTS: The study involved patients with HF and CKD from the database of the Chronic Renal Insufficiency Cohort (CRIC) study. The study endpoint includes the following: (i) primary endpoint, including cardiovascular disease (CVD) events, renal events, and all‐cause death; (ii) CVD events; (iii) renal events; and (iv) all‐cause death. Among 3939 participants in the CRIC study, a total of 382 patients were included. The duration of the follow‐up was 6.3 ± 2.7 years, the age was 60.2 ± 8.9 years, and 57.6% were male. BP index included 20 indicators in relation to BP level and variability, 4 of which were analysed including baseline systolic BP (SBP), standard deviation of SBP, coefficient of variation of diastolic BP (DBP CV), and average real variability of pulse pressure. In the Cox regression analysis after adjustment, baseline SBP was significant for the risk of primary endpoint [hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.03–1.44, P = 0.02] and renal events (HR 1.54, 95% CI 1.22–1.95, P < 0.001), and DBP CV was significant for the risk of primary endpoint (HR 1.03, 95% CI 1.01–1.06, P = 0.02) and CVD events (HR 1.04, 95% CI 1.02–1.07, P < 0.01). The result of the forest plot depicted that baseline SBP had a linear association with the risk of CVD and renal events (P = 0.04 and 0.001, respectively) and DBP CV with CVD events (P = 0.02). As the restricted cubic spline models displayed, DBP CV featured a J‐ or L‐curved association with the primary endpoint, renal events, and all‐cause death (P for nonlinearity = 0.01, <0.001, and 0.01, respectively). CONCLUSIONS: The baseline SBP and DBP CV may remain significant for clinical outcomes in patients with both HF and CKD. The increase in baseline SBP is associated with a higher risk of primary endpoint, CVD events, and renal events, and the increase in DBP CV with a higher risk of CVD events. Concerning nonlinear association, DBP CV features a J‐ or L‐curved relationship with the primary endpoint, renal events, and all‐cause death, with a higher risk at both low and high values. Trial registration: https://www.clinicaltrials.gov; unique identifier: NCT00304148.