Systolic Blood Pressure Trajectories and Acute Kidney Injury After Spontaneous Intracerebral Hemorrhage.

BACKGROUND: Early systolic blood pressure (SBP) lowering is standard after spontaneous intracerebral hemorrhage (ICH), but renal effects of rapid or sustained reductions in clinical practice remain uncertain. METHODS: We conducted a single-center retrospective study of 233 adults admitted to an intensive care unit with ICH (2011-2023). Hourly SBP measurements over 130 hours were z-normalized and analyzed using k-Shape clustering. The primary outcome was Kidney Disease: Improving Global Outcomes-defined acute kidney injury (AKI) within 7 days. Multivariable logistic regression adjusted for admission SBP and baseline covariates; modified Poisson regression estimated adjusted risk ratios. RESULTS: Cluster 1 (n=111; mean admission SBP, 161.7 mm Hg) had lower initial SBP, early decline, and rebound; Cluster 2 (n=122; 179.7 mm Hg) had higher initial SBP, rapid decline, and stabilization at lower levels. AKI occurred in 70 (63.1%) Cluster 1 patients and 94 (77.0%) Cluster 2 patients (crude odds ratio [OR], 1.97; 95% CI, 1.11-3.48). The adjusted cluster OR was 1.95 (95% CI, 1.07-3.56) without admission SBP and 1.63 (95% CI, 0.87-3.04; P=.124) after its inclusion; the adjusted risk ratio was 1.15 (95% CI, 0.97-1.36). Admission SBP was associated with AKI (adjusted OR 1.14; 95% CI, 1.04-1.24). CONCLUSIONS: In adults with ICH, the higher-initial SBP trajectory was associated with a higher unadjusted frequency of AKI; however, this association was no longer statistically significant after accounting for admission SBP and baseline covariates. These findings highlight the importance of presenting BP but do not establish that intensive BP lowering causes renal injury and need for further prospective study.