#2984 ACHIEVED BLOOD PRESSURE AND CARDIOVASCULAR OUTCOMES IN PATIENTS WITH ADVANCED STAGE CHRONIC KIDNEY DISEASE
Authors: Al-Sodany Ehab , Szummer Karolina , Barany Franz Peter , Heimbürger Olof , Evans Marie 
Published: June 2023

Abstract

Background and Aims
In patients with severely decreased eGFR (stage 4-5 CKD), efficacy of treating patients to a lower blood pressure (BP) target is uncertain. The Systolic blood PRessure INtervention Trial (SPRINT) demonstrated lower rates of a composite cardiovascular (CVD) endpoint and death in the intensive treatment group with a target systolic blood pressure (SBP) of &lt;120 mmHg. This study has influenced guidelines; the updated 2021 Kidney Disease Improving Global Outcomes (KDIGO) now suggest lowering the SBP to &lt; 120 mmHg, if tolerated. In this study we set out to investigate the association between SBP and CVD in a large cohort of nephrology-referred patients with CKD stage 3-5.

Method
We included patients ≥18 years participating in the Swedish Renal Registry (SRR-CKD) who had a first registered eGFR &lt;60 ml/min/1.73 m2 2006-2017 with at least one recorded BP measurement and two out-patient visits within one year. We excluded individuals with a recorded SBP &lt;100 mmHg or prior kidney failure replacement treatment. After the initial one-year observation period, we followed patients until the primary or secondary outcome was attained, or until December 31, 2017. The achieved average systolic BP, measured during routine out-patient care using any standard electronic or manual blood pressure device, was categorized into a priori defined categories. To align with SPRINT, the primary endpoint was Major Cardiovascular Events (MACE) defined as the composite of first myocardial infarction (MI), non-MI acute coronary syndrome, stroke, heart failure, or death attributable to CVD. The secondary endpoints were the individual components of the primary composite endpoint, all-cause death, or a composite of the primary endpoint and death. Demographics, body mass index, underlying kidney disease, and laboratory values at the start of follow-up were obtained from the SRR-CKD. Information on comorbidity, including Charlson comorbidity index was gathered from a linkage with the National Patient Registry; medications were obtained from the National Prescribed drug register. The primary endpoint and secondary endpoints were assessed by cause-specific Cox proportional hazards regression, adjusting for age, sex, history of CVD, Charlson comorbidity, plasma albumin, phosphate, diuretics, RAASi, betablockers, eGFR, and diastolic blood pressure. Missing data were handled through multiple imputation.

Results
In total 15,668 patients with a median eGFR 23 ml/min/1.73 m2, mean age 71 years and 33% women were followed over a period of 2.8 years (IQR 1.4-5.0). There were 6359 patients (41%) experiencing the primary outcome; 2601 (17%) with a coronary artery event, 1427 (9%) MI, 1,345 (9%) cerebrovascular event, and 5,480 (35%) patients died. The unadjusted analysis showed a J-shaped relationship between SBP and the primary outcome, with the lowest risk of events in patients with SBP around 125 mmHg (Figure 1). In multivariable models, there was a higher risk of experiencing the primary outcome if the average SBP was &gt;150 mmHg (HR 1.09;95%CI 1.0-1.19), the highest risk being in those with SBP above 160 mmHg (HR 1.40 with 95% CI 1.28-1.53) as compared to those with SBP 130-140 mmHg (Figure 2). We observed 30% lower risk of MI when the SBP was 100–120 mmHg after adjustments (HR 0.70 (95% CI 0.56–0.88) as compared to 130–140, and higher risk of MI at SBP &gt;160 mmHg (1.78; 1.49–2.12) with 11% higher risk of MI with every 10 mmHg increase in SBP (HR 1.11; 1.07–1.14). The other cardiovascular endpoints, including all-cause mortality showed a similar pattern as the primary composite endpoint.

Conclusion
In patients with advanced stage CKD, SBP &lt;120 mmHg is associated with lower risk of MI, but not with lower risk of other cardiovascular outcomes or all-cause mortality. A SBP &gt;140 mmHg was associated with higher risk of most cardiovascular events including cardiovascular mortality and all-cause mortality.