Abstract:Objective To investigate the correlation between neutrophil to lymphocyte ratio（NLR）and coronary heart disease（CHD）in chronic obstructive pulmonary disease（COPD），and to provide a reference for early prediction of CHD in COPD patients. Methods Using a cross-sectional method，121 severe COPD patients admitted to Jiangyin People’s Hospital and Nanjing Chest Hospital from January 2022 to March 2024 were selected as study subjects. Patients’ general clinical data were collected through the electronic medical record system. Those with concurrent CHD were included in the COPD+ CHD group（n=60），while those without CHD were included in the COPD group（n=61）. The levels of NLR and other indicators in peripheral blood of two groups were detected，and a multivariate logistic regression model was used to analyze the risk factors for the occurrence of CHD in COPD patients. The receiver operating characteristic（ROC）curve was used to assess the predictive value of NLR for secondary CHD in COPD patients. Results Suffering from hypertension（OR=2.965，95%CI：1.120-7.850，P=0.029），high CRP（OR=1.013，95%CI：1.001-1.024，P=0.027）and high NLR（OR=2.499，95%CI：1.081-5.779，P=0.032）were the risk factors for CHD in patients with severe COPD（P <0.05）. According to the ROC curve，when NLR was used alone，the area under the curve（AUC）was 0.768，the cut-off value of NLR was 5.601. When NLR > 5.601，the incidence of CHD was significantly increased，with the sensitivity of45%，and the specificity of 100%；when NLR，hypertension and CRP were used as the combined prediction，the diagnostic efficacy was better，with an AUC of 0.823. Conclusion The detection of NLR in peripheral blood has an important clinical value in predicting the occurrence of CHD in patients with severe COPD.