Association between early systolic blood pressure and clinical outcomes in non-critically ill patients with sepsis-associated acute kidney injury: a retrospective cohort study

Abstract

Background Sepsis-associated acute kidney injury (SA-AKI) is associated with poor outcomes. Evidence regarding the relationship between early systolic blood pressure (BP) and clinical outcomes in non-critically ill patients with SA-AKI remains limited. This study aimed to investigate the association between mean systolic BP during the first 48 h after admission and one-year clinical outcomes in this population.Methods We conducted a single-center retrospective cohort study of non-critically ill adults with SA-AKI admitted between 2011 and 2020. SA-AKI was defined by a sequential organ failure assessment (SOFA) score increase ≥2 and AKI occurring within 48 h of admission. The exposure was mean systolic BP over the first 48 h (seven measurements at baseline and every 8 h), categorized as ≤100, 101–120, 121–140, and >140 mmHg. Patients were followed for one year. The primary outcome was a composite of ≥25% decline in estimated glomerular filtration rate, long-term dialysis, and one-year mortality.Results Of 2,920 screened patients, 476 were included. Mean age was 68.4 ± 14.5 years, and 55% were male. AKI stages I, II, and III occurred in 55%, 21%, and 24%, respectively. The primary composite outcome was most frequent in the ≤100 mmHg group (80%) compared with 101–120 (51%), 121–140 (50%), and >140 mmHg (46%) (p < 0.001). In adjusted analyses, mean systolic BP ≤100 mmHg was associated with higher composite outcome (HR 1.84, 95% CI 1.15–2.93; p = 0.010). One-year mortality was highest in systolic BP ≤100 mmHg group (73% vs. 32% in 121–140 mmHg; p < 0.001), with increased adjusted hazards for one-year mortality (HR 2.89, 95% CI 1.68–4.99) and 30-day mortality (HR 2.79, 95% CI 1.12–6.96).Conclusion In non-critically ill patients with SA-AKI, early mean systolic BP ≤100 mmHg within 48 h was associated with worse one-year outcomes, driven largely by higher mortality. Early systolic BP may serve as a prognostic marker for high-risk patients.