Aims: Improving renal function (IRF) is paradoxically associated with worse outcomes in acute heart failure (AHF), but outcomes may differ based on response to decongestion. We explored if the relationship of IRF with mortality in hospitalized AHF patients differs based on successful decongestion. Methods and results: We evaluated 760 AHF patients from AKINESIS for the relationship between IRF, change in B‐type natriuretic peptide (BNP), and 1‐year mortality. IRF was defined as a ≥20% increase in estimated glomerular filtration rate (eGFR) relative to admission. Adequate decongestion was defined as a ≥40% decrease in last measured BNP relative to admission. IRF occurred in 22% of patients who had a mean age of 69 years, 58% were men, 72% were white, and median admission eGFR was 49 mL/min/1.73 m ² . IRF patients had more severe heart failure reflected by lower admission eGFR, higher blood urea nitrogen, lower systolic blood pressure, lower sodium, and higher use of inotropes. IRF patients had higher 1‐year mortality (25%) than non‐IRF patients (15%) ( P < 0.01). However, this relationship differed by BNP trajectory ( P ‐interaction = 0.03). When stratified by BNP change, non‐IRF patients and IRF patients with decreasing BNP had lower 1‐year mortality than either non‐IRF and IRF patients without decreasing BNP. However, in multivariate analysis, IRF was not associated with mortality [adjusted hazard ratio (HR) 1.0, 95% confidence interval (CI) 0.7–1.5] while BNP was (adjusted HR 0.5, 95% CI 0.3–0.7). When IRF was evaluated as transiently occurring or persisting at discharge, again only BNP change was significantly associated with mortality. Conclusion: Improving renal function is associated with mortality in AHF but not independent of other variables and congestion status. Achieving adequate decongestion, as reflected by lower BNP, in AHF is more strongly associated with mortality than IRF.

BACKGROUND: Worsening renal function (WRF) is common in hospitalized patients being treated for acute heart failure. However, discriminating clinically significant WRF remains challenging. In patients hospitalized with acute heart failure, we evaluated if blood and urine biomarkers of cardiac and kidney dysfunction were associated with adverse outcomes. METHODS: We identified 175 of 927 participants in the AKINESIS study (Acute Kidney Neutrophil Gelatinase-Associated Lipocalin Evaluation of Symptomatic Heart Failure Study) who met criteria for stage 1 or 2 Kidney Disease: Improvement Global Outcomes acute kidney injury during the first 3 days of hospitalization. We measured 24 blood and urine biomarkers from specimens collected within 24 hours of meeting acute kidney injury criteria. The primary composite outcome consisted of worsening WRF (higher acute kidney injury stage), need for dialysis, or death at 30 days. Biomarkers’ association with the composite outcome was assessed with logistic regression by tertiles and area under the curve (AUC). RESULTS: Of the 175 participants, 32 (18%) developed the primary composite outcome. Only history of chronic kidney disease was significantly different between those with and without the composite outcome. The highest tertile of plasma Gal-3 (galectin-3) and urine epidermal growth factor were associated with increased odds of the composite outcome compared with the lowest tertile in unadjusted analyses. After adjusting for serum creatinine, systolic blood pressure, and blood urea nitrogen, only the highest tertile of Gal-3 was associated with greater odds of the composite outcome (odds ratio, 4.6 [95% CI, 1.4–16.0). Gal-3 had the highest AUC (0.70 [95% CI, 0.58–0.82]), while epidermal growth factor had a lower AUC (0.63 [95% CI, 0.53–0.74]). Notably, urine biomarkers of kidney tubule injury were not associated with the composite outcome. CONCLUSIONS: Tubular injury does not occur in most patients with acute heart failure experiencing WRF, consistent with the functional mechanisms of WRF in this patient population. REGISTRATION: URL: https://www.clinicaltrials.gov/study/NCT01291836?term=NCT01291836&rank=1 ; Unique identifier: NCT01291836.