Blood pressure response index and acute kidney injury progression in heart failure patients: a retrospective cohort study from MIMIC-IV

In heart failure (HF), acute kidney injury (AKI) is an independent risk factor of mortality, and severer stage of AKI is associated with poorer prognosis. Blood pressure response index (BPRI) reflects the cardiovascular response to vasoactive drugs which are commonly used to increase perfusion to the vital organs. We sought to investigate the association between BPRI and AKI progression in HF patients. This was a retrospective cohort study collected the data from MIMIC-IV version 3.0. We collected the minimum value of BPRI within 24 hours of ICU admission (T0). The AKI progression was defined as an increase of at least one AKI stage within 48 hours after T0 (T1). The new incidence of AKI at T1 was also considered as AKI progression. The patients were divided into four distinct groups based on the quartiles of the BPRI. A total of 3147 patients with HF were included, of whom 1883 (59.8%) were male and a median age of 73.80 [64.50, 82.33] years. 1571 (49.9%) experienced AKI progression. The quartiles 1 group exhibited the lowest 90-day survival rate, especially in patients who developed AKI progression (all log-rank p < 0.001). Compared to the patients in quartiles 1, those in higher quartiles had a significantly lower risk of AKI progression (in full-adjusted model: quartiles 2 OR 0.94, 95% CI 0.77–1.17, p = 0.594; quartiles 3 OR 0.64, 95% CI 0.52–0.79, p < 0.001; quartiles 4 OR 0.70, 95% CI 0.56–0.87, p = 0.001). There was an asymmetric U-shaped relationship between BPRI and AKI progression, with a cutoff value of 12.0 (P-overall < 0.001, P-non-linear < 0.001). Similar results in stratified analyses based on the AKI situation (without AKI, AKI stage 1, AKI stage 2) at T0 were observed (compared to quartiles 1 group, the OR of other quartiles group were less than 1). When below the cut-off, a lower BPRI within the first 24 hours of ICU admission is associated with increased risk of AKI progression in the following 48 hours among HF patients, regardless of initial AKI situation.