Peripheral blood NMLR can predict 5-year all-cause mortality in patients with chronic obstructive pulmonary disease

<bold>Background:</bold> Chronic obstructive pulmonary disease (COPD) is an inflammatory disease with a high mortality. Peripheral blood (neutrophil + monocyte)/lymphocyte ratio (NMLR) has been used as a prognostic indicator for several inflammatory diseases. However, it is unknown whether the peripheral blood NMLR can predict the prognosis of COPD. <bold>Methods:</bold> This retrospective study included 870 COPD inpatients due to the acute exacerbation, and 5-year all-cause mortality of these patients was recorded. Kaplan-Meier method was used to compare the death risk of COPD patients according to the NMLR value. Multivariable COX hazard regression and restricted cubic spline models were used to assess the relationship between NMLR and 5-year all-cause mortality of COPD. <bold>Results:</bold> The NMLR value was significantly increased in non-survivors compared with the survivors (P=0.000). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for predicting 5-year all-cause mortality in patients with COPD was 0.63. Kaplan-Meier survival curves showed that 5-year all-cause mortality of COPD patients was significantly increased when the admission peripheral blood NMLR ≥ 5.90 (P=0.000). COX regression model showed that NMLR was an independent predictor of 5-year all-cause mortality in COPD patients (P=0.001). Moreover, there was a positive correlation between admission NMLR value and death risk of COPD patients by the restricted cubic spline analysis (P-Nonlinear=0.0018). <bold>Conclusion:</bold> Admission peripheral blood NMLR is a strong predictor for 5-year all-cause mortality of COPD patients, and the high NMLR values may suggest a poor clinical prognosis.