Background: Regardless of patients' baseline renal function, worsening renal function (WRF) during hospitalization is associated with poor outcomes. In individuals with acute heart failure (AHF), one predictor of WRF is an early drop in systolic blood pressure (SBP). Few studies have investigated WRF in elderly AHF patients or the influence of these patients' at-admission heart rate (HR) on the relationship between an early SBP drop SBP and the AHF.
Methods: We measured the SBP and HR of 245 elderly AHF inpatients (82.9±6.0 years old, females 50.6%) at admission and another six times over the next 48 hr. We defined 'WRF' as a serum creatinine increase ≥0.3 mg/dL by Day 5 post-admission. We calculated the 'early SBP drop' as the difference between the admission SBP value and the lowest value during the first 48 hr of hospitalization.
Results: There were significant differences between the 36 patients with WRF and the 209 patients without WRF: early SBP drop (51.3 vs. 32.5 mmHg, p<0.01) and at-admission HR (79.3 vs. 89.6 bpm, p<0.05), respectively. In the multiple logistic regression analysis adjusted for the confounders, early SBP drop (OR: 1.003, 95%CI: 1.003–1.03, p<0.04) and HR at-admission (OR: 0.98, 95%CI: 0.96–0.99, p<0.01) were significantly associated with WRF. No significant association was shown for the interaction term of early SBP drop ´ at-admission HR with WRF (p=0.3).
Conclusions: In these elderly AHF patients, exaggerated early SBP drop and lower at-admission HR were significant independent predictors of WRF, and these factors were additively associated with WRF.