Association of NLR with all-cause and cardiovascular mortality in adults with coronary heart disease: 1999–2018 NHANES data analysis

The neutrophil-to-lymphocyte ratio (NLR) is an important inflammatory marker. However, the relationship between NLR and the prognosis of patients with coronary heart disease (CHD) remains unclear. The purpose of this study is to explore the relationship between NLR and all-cause mortality and cardiovascular mortality in CHD patients. This study analyzed data from 1625 CHD patients who participated in the National Health and Nutrition Examination Survey from 1999 to 2018. Multivariate Cox regression analysis was used to explore the relationship between mortality risk and NLR. The optimal NLR cutoff value related to survival outcomes was determined using the maximum selected rank method. Restricted cubic spline analysis was performed to investigate the correlation between NLR and mortality risk in CHD patients. Moreover, subgroup analyses were conducted to assess the relationship between NLR and all-cause and cardiovascular mortality in different populations. Additionally, time-dependent receiver operating characteristic curves were used to evaluate the accuracy of NLR in predicting survival outcomes. During a median follow-up of 88 months, a total of 475 patients experienced all-cause mortality, and 278 patients experienced cardiovascular mortality. After adjusting for confounding factors, compared with CHD patients with higher NLR, those with lower NLR had a 43% reduced risk of all-cause mortality (hazard ratio: 0.57, 95% CI: 0.41-0.8) and a 51% reduced risk of cardiovascular mortality (hazard ratio: 0.49, 95% CI: 0.3-0.78). Kaplan-Meier analysis showed that the survival rate in the high NLR group was significantly lower in terms of all-cause and cardiovascular mortality rates than in the low NLR group (P < .0001). The results of the restricted cubic spline analysis indicated a nonlinear relationship between NLR and all-cause mortality as well as cardiovascular mortality in CHD patients. In addition, receiver operating characteristic analysis showed that the area under the curve for all-cause mortality at 3 years, 5 years, and 10 years were 0.596, 0.591, and 0.604, while the area under the curve for cardiovascular mortality were 0.623, 0.617, and 0.623, in CHD patients. Elevated NLR is associated with increased risk of cardiovascular and all-cause mortality in CHD patients, and NLR can independently predict the prognosis of CHD patients.