The Association Between the CALLY Index and All-Cause Mortality in Patients with COPD: Results from the Cohort Study of NHANES 2007–2010

Purpose:The C-reactive protein (CRP)-albumin-lymphocyte (CALLY) index is a newly developed biomarker that combines measurements of CRP, serum albumin, and lymphocyte count.This index provides a thorough assessment of a patient's inflammation level, nutritional condition, and immunological function.The objective of this study is to examine the correlation between the CALLY index and all-cause mortality in COPD patients.Methods: We calculated the CALLY index using data from the National Health and Nutrition Examination Survey (NHANES) for the 2007-2008 and 2009-2010 cycles, extracted from the participants' peripheral blood samples.The study utilized Kaplan-Meier curves, restricted cubic spline (RCS) curves, and Cox regression analysis to evaluate the relationship between the CALLY index and the risk of all-cause mortality in COPD patients.To assess the predictive accuracy of the CALLY index, we calculated the area under the receiver operating characteristic (ROC) curve (AUC). Results:The study included 1,048 participants and found a significant negative correlation between the CALLY index and all-cause mortality in patients with COPD.The CALLY index was a major predictor of survival in COPD patients [fully adjusted model: in the 3rd quartile, HR = 1.61, 95% CI: 1.02-2.52,p = 0.039; in the 2nd quartile, HR = 2.11, 95% CI: 1.22-3.65,p = 0.008; in the 1st quartile, HR = 3.12, 95% CI: 2.00-4.85,p < 0.001].The RCS curves demonstrated a non-linear association between the CALLY index and all-cause mortality in COPD patients.The areas under the curve (AUC) in predicting 5-and 10-year all-cause mortality were 0.693 and 0.656. Conclusion:The CALLY index has a strong relationship with all-cause mortality in patients with COPD in the US and could serve as a prognostic biomarker for these patients.