Abstract Background and Aims Organ crosstalk in heart failure and kidney dysfunction is prevalent and is associated to a high event rate. In this setting elevated serum creatinine (sCr) at acute decompensated heart failure (ADHF) admissions is a strong risk factor for poor outcomes. Current accepted cardiorenal syndrome (CRS) classification is based on timing and initial organ dysfunction and fails at capturing its nature and prognosis. We sought to describe patient (P) profile and outcomes in P hospitalized for ADHF with high admission sCr in function of current CRS classification and assess for stratifying predictors. Method We conducted an observational, analytical and cross-sectional study, with prospective and consecutive data acquisition. We included P over 18 years-old, who were admitted to the Intensive Care Telemetry Unit in our Hospital between July, 2011 and Dec, 2023 due to ADHF. P who received a heart transplant during index admission or those on chronic dialysis were excluded. Clinical, epidemiological and biochemical variables were registered. Renal dysfunction was defined under admission sCr >1.4 mg/dl and divided according to Ronco et al classification, as initially cardiac (type 2) or renal (type 4) origin. We constructed multivariate logistic and survival regression models, with selection of relevant predictors by resampling and regularization of a Lasso regression model. Statistical significance was considered with a 5% of alpha error level. Analysis was conducted using R (R Core Team, 2023). Results A total of 1868 consecutive P were included. P population consisted in type 2: 124 and type 4: 258 P, respectively. We found no differences in gender (p = 0.47), while type 4 were older (75 ± 12 vs 71 ± 12; p < 0.01). Ventricular dysfunction was more severe in type 2 (left ventricular ejection fraction 34 ± 17 vs 41 ± 16%; p < 0.001). While ischaemic heart disease was more prevalent in type 4 (32.8 vs 23.5%; p = 0.001), idiopathic cardiomyopathy was more frequent in type 2 (18.8 vs 7.2%; p = 0.001). Clinical phenotypes differed between groups, being clinical hypoperfusion more frequent in type 2 (32.4 vs 12.3%; p < 0.001). Admission sCr was higher in type 4 (1.9 [0.8] vs 1.6 [0.58] mg/dl; p < 0.001), as was 1st day natriuresis (81 vs 67 mEq; p = 0.01). Both groups experienced a similar diuretic resistance rate (21.2 vs 17.1%; p = 0.34), while type 4 received rescue ultrafiltration more frequently (11.3 vs 3.5%; p < 0.01). Type 2 received a higher inotropic support rate (47.1 vs 19.5%; p < 0.01) and had a longer length of stay (9 vs 7 days; p = 0.01). In-hospital (11.8 vs 11.3%; p = 0.99); 6-month and 1-year mortality rates (66.8 vs 72.8% and 55.1 vs 64.6% respectively; p = 0.3). In a similar way, 1-month (94.8 vs 94.7%), 6-month (72 vs 74.7%) and 1-year readmission rates (59.2 vs 60.9%; p = 0.6) were similar in both groups. A multiple logistic regression model (AUCROC 0.82) identified admission sCr (OR 2.6; CI 95% 2.2-3.2; p < 0.001), inotropic need (OR 1.87; CI 95% 1.4-2.6; p < 0.001), anasarca phenotype (OR 1.63; CI 95% 1.06-2.5; p = 0.02), moderate to severe right ventricular dysfunction (OR 1.4; CI 95% 1.03-1.9; p = 0.03) as independent predictors for a descending sCr behavior during hospitalization, while the lower T3 levels were associated with less probability for a descent of sCr (OR 0.21; CI 95% 0.1-0.46; p < 0.001). Conclusion Organ crosstalk in ADHF hospitalizations was associated with a high event rate. One-year mortality and readmission rates were similar in both groups. Renal support therapies were more frequent under lower kidney reserve conditions. Ventricular dysfunction and systemic congestion phenotype are relevant to a better understanding for potential reversibility at the admission time and may promote actions for outcome enhancing.