A Tri-Component (Glomerular, Tubular, and Metabolic) Assessment of Renal Function in Acute Heart Failure

<b>Background</b>: Despite the prevalence of impaired renal function in acute heart failure (AHF) patients, the intricate relationship between glomerular, tubular, and metabolic renal function remains unexplored. We aimed to investigate the co-occurrence of glomerular, tubular, and metabolic renal dysfunction in AHF and their impact on prognosis. <b>Methods</b>: eGFR, spot urine sodium, and HCO^3- were measured in 243 patients hospitalized for AHF. The population was stratified by the 4-point renal dysfunction score and linked with outcomes. <b>Results</b>: Glomerular dysfunction exhibited an elevated risk of death (HR of 2.04; 95% CI [1.24-3.36]; <i>p</i> = 0.006), combined risk of death, and HF rehospitalization (HR of 2.03; 95% CI [1.34-3.05]; <i>p</i> = 0.005). Similarly, tubular dysfunction correlated with a higher death risk (HR of 1.72; 95% CI [1.04-2.82]; <i>p</i> = 0.03) and a higher combined risk (HR of 1.82; 95% CI [1.21-2.74]; <i>p</i> = 0.004). While renal metabolic dysfunction was linked to increased death risk (HR of 1.82; 95% CI [1.07-3.11]; <i>p</i> = 0.028), it was not associated with composite risk (HR of 1.37; 95% CI [0.88-2.15]; <i>p</i> = 0.174). Multivariate analysis revealed a direct association between the renal dysfunction score and death risk (HR of 1.92 per 1 point; 95% CI [1.47-2.52]; <i>p</i> < 0.0001) and the combined risk of death and HF rehospitalization (HR of 1.78 per 1 point; 95% CI [1.43-2.22]; <i>p</i> < 0.0001). <b>Conclusions</b>: Renal dysfunction is common, with varied overlaps. Glomerular, tubular, and metabolic dysfunctions predict adverse outcomes in AHF. The established renal score may aid patient stratification and prognosis.