Difference in the ratio of low-density lipoprotein to lymphocytes between acute exacerbation of and stable phase of chronic obstructive pulmonary disease patients.

OBJECTIVE: To examine difference in the low-density lipoprotein cholesterol/lymphocyte (LDL-C/LYM) ratio between the acute exacerbation and stable phases of chronic obstructive pulmonary disease (COPD) and assess its diagnostic and prognostic value. METHODS: A total of 196 hospitalized COPD patients were retrospectively analyzed, including 96 in the acute exacerbation phase and 100 in the stable phase. Demographics, inflammatory markers [C-reactive protein (CRP), interleukin-6 (IL-6), white blood cell count (WBC), monocyte percentage (MO%)], pulmonary function indices [percentage of predicted forced expiratory volume in one second (FEV1% pred), FEV1/forced vital capacity (FVC), peak expiratory flow (PEF)], and LDL-C/LYM ratios were collected. Intergroup comparisons, correlation analyses, and receiver operating characteristic (ROC) curve analysis were performed. RESULTS: LDL-C/LYM ratio was significantly higher during acute exacerbation (P < 0.001), positively correlated with CRP, IL-6, WBC, and MO% (r = 0.404-0.606), and negatively with FEV1% pred, FEV1/FVC, and PEF (r = -0.310 to -0.402) (all P < 0.001). No significant correlation between LDL-C/LYM ratio and pulmonary function indices were found in the stable group. ROC analysis showed that the LDL-C/LYM ratio had the highest diagnostic accuracy for acute exacerbation [area under the curve (AUC) = 0.828], outperforming other markers, and it correlated positively with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging (r = 0.419, P < 0.001). CONCLUSION: The LDL-C/LYM ratio is elevated during COPD exacerbations and reflects inflammation and lung function decline, serving as a simple biomarker for diagnosis and prognosis.