Prognostic Significance of the CALLY Index in Heart Failure

Background: Heart failure (HF) is a global health problem with high mortality rates. Systemic inflammation and neurohumoral dysfunction play an important role in its pathophysiology. Unlike other subtypes, HF with preserved ejection fraction (HFpEF) represents a highly heterogeneous group of patients. Therefore, the phenotyping must be conducted with great care. Objective: In our study, we aimed to evaluate the relationship between the C-reactive protein-albumin-lymphocyte (CALLY)-index, a composite biomarker reflecting the nutritional, inflammation and immune status of the patient, and long-term mortality due to all causes in HF. Subjects and Methods: Our retrospective, single-centre study included patients diagnosed with HF and followed up at our clinic between 2018-2025. The CALLY-index was calculated using the patients' blood tests at the time of hospital admission. In this study, where the primary endpoint was all-cause mortality, patients were divided into two groups according to their survival status. Variables independently associated with mortality were identified using Cox-regression analysis. To assess the predictive power of the CALLY-index for mortality, a Receiver Operating Characteristic (ROC) analysis was performed and the area under the curve (AUC) was calculated. Results: Our study included 1541 patients, with a mean age of 69.39±12.82, 758 (49.2%) males, and a mean follow-up period of 5.51±2.37 years. The all-cause mortality rate in the sample was 9.6% (148 patients). Consequently, the CALLY-index showed an independent association with mortality in HF (P=0.002) and predicted mortality with a cut-off value of 0.43, a sensitivity of 66.2% and a specificity of 66.2% (AUC:0.715, P=0.001). When regression analyses were repeated by subgroup, an independent association between the CALLY-index and mortality was identified only in the HFpEF group, unlike in the others. In HFpEF, the CALLY-index predicted mortality with a sensitivity of 68.8% and a specificity of 68.7% at a cut-off value of 0.40 (AUC:0.744, P<0.001). Conclusion: This study has shown that the CALLY index may have prognostic value in HF, particularly in HFpEF. We believe that this could be important in identifying high-risk patients in HF.