Prognostic value of the CALLY index for predicting in-hospital mortality in community-acquired pneumonia: Results from an elderly-predominant cohort.

OBJECTIVE: Community-acquired pneumonia (CAP) remains a major cause of morbidity and mortality, particularly among older adults. This study aimed to evaluate the prognostic performance of the C-reactive protein-albumin-lymphocyte (CALLY) index for predicting in-hospital mortality in patients with CAP. Secondary analyses compared its discriminatory performance with the Pneumonia Severity Index (PSI) and CURB-65 and evaluated its association with mortality after adjustment for these established severity scores. MATERIALS AND METHODS: This single-center, prospective observational study included 190 hospitalized patients with CAP presenting to the emergency department. The CALLY index was calculated from laboratory parameters obtained at admission. Receiver operating characteristic (ROC) curve analysis was used to assess discrimination for in-hospital mortality, and optimal cutoff values were determined using the Youden index. The areas under the ROC curves (AUCs) of CALLY, PSI, and CURB-65 were compared using DeLong's test. Parsimonious multivariable logistic regression models were used to evaluate the association between CALLY and mortality after separate adjustment for PSI and CURB-65. RESULTS: The median age was 77 years (IQR, 68-82), 122 patients (64.2%) were male, and 64 (33.7%) died during hospitalization. The CALLY index was numerically lower among non-survivors than survivors (0.20 [IQR, 0.08-0.80] vs. 0.29 [IQR, 0.16-0.69]; p = 0.065). CALLY demonstrated limited discrimination for in-hospital mortality (AUC, 0.582; 95% CI, 0.489-0.675). At the optimal cutoff of ≤ 0.142, sensitivity was 42.2% and specificity was 81.0%. PSI (AUC, 0.814; 95% CI, 0.753-0.875) and CURB-65 (AUC, 0.712; 95% CI, 0.639-0.785) demonstrated significantly greater discrimination than CALLY (DeLong p < 0.001 and p = 0.041, respectively). CALLY was not independently associated with mortality after adjustment for either PSI (adjusted OR per doubling, 0.875; 95% CI, 0.729-1.052; p = 0.155) or CURB-65 (adjusted OR per doubling, 0.851; 95% CI, 0.712-1.017; p = 0.076). CONCLUSION: In this elderly-predominant CAP cohort, the CALLY index showed limited discriminatory performance for in-hospital mortality and was not independently associated with mortality after adjustment for established CAP severity scores. PSI and CURB-65 demonstrated significantly better discrimination. These findings suggest limited utility of CALLY as a standalone prognostic marker in this population and warrant external validation in larger, multicenter cohorts.