Association of Acute Kidney Injury with Cardiovascular Events and Death in Systolic Blood Pressure Intervention Trial.

RATIONALE AND OBJECTIVE: In the Systolic Blood Pressure Intervention Trial, the possible relationships between acute kidney injury (AKI) and risk of major cardiovascular events and death are not known.

STUDY DESIGN: Post hoc analysis of a multicenter, randomized, controlled, open-label clinical trial.

SETTING AND PARTICIPANTS: Hypertensive adults without diabetes who were ≥50 years of age with prior cardiovascular disease, chronic kidney disease (CKD), 10-year Framingham risk score > 15%, or age > 75 years were assigned to a systolic blood pressure target of < 120 mm Hg (intensive) or < 140 mm Hg (standard).

PREDICTOR: AKI episodes.

OUTCOMES: The primary outcome was a composite of myocardial infarction, acute coronary syndrome, stroke, decompensated heart failure, or cardiovascular death. The secondary outcome was death from any cause. Analytical Approach: AKI was defined using the Kidney Disease: Improving Global Outcomes modified criteria based solely upon serum creatinine. AKI episodes were identified by serious adverse events or emergency room visits. Cox proportional hazards models assessed the risk for the primary and secondary outcomes by AKI status.

RESULTS: Participants were 68 ± 9 years of age, 36% women (3,332/9,361), and 30% Black race (2,802/9,361), and 17% (1,562/9,361) with cardiovascular disease. Systolic blood pressure was 140 ± 16 mm Hg at study entry. AKI occurred in 4.4% (204/4,678) and 2.6% (120/4,683) in the intensive and standard treatment groups respectively (p < 0.001). Those who experienced AKI had higher risk of cardiovascular events (hazard ratio [HR] 1.52, 95% CI 1.05-2.20, p = 0.026) and death from any cause (HR 2.33, 95% CI 1.56-3.48, p < 0.001) controlling for age, sex, race, baseline systolic blood pressure, body mass index, number of antihypertensive medications, cardiovascular disease and CKD status, hypotensive episodes, and treatment assignment.

LIMITATIONS: The study was not prospectively designed to determine relationships between AKI, cardiovascular events, and death.

CONCLUSIONS: Among older adults with hypertension at high cardiovascular risk, intensive treatment of blood pressure independently increased risk of AKI, which substantially raised risks of major cardiovascular events and death.