BACKGROUND Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is associated with infective triggers including bacterial or viral in many cases, and pneumonia is a major contributor to hospitalization for AECOPD and has a close relationship with poor outcomes. Increased delta neutrophil index (DNI) can be useful in the detection of COPD patients with pneumonia. METHODS A retrospective cohort study was performed to investigate the mortality rate of the patients who were re-admitted within 6 months after discharge from the hospital due to AECOPD with or without CAP. We analyzed the difference of cumulative survival rate according to serum DNI level and readmission duration. RESULTS Finally, 140 AECOPD patients with community-acquired pneumonia (CAP) and 174 AECOPD patients without CAP were enrolled during 6 months, respectively. The mean age was 72.2 ± 9.4 year-old, and 240 patients (76.4%) were male. When comparing the cumulative survival rate according to readmission duration (≤ 30 vs >  30 days) and DNI level (< 3.5 vs ≥ 3.5%), AECOPD patients with readmission ≤30 days and DNI ≥ 3.5% showed the lowest cumulative survival rate compared to other groups (P <  0.001). Multivariate analysis revealed readmission duration ≤30 days (HR 7.879, 95% CI 4.554-13.632, P <  0.001); and serum DNI level (HR 1.086, 95% CI 1.043-1.131, P <  0.001) were significantly associated with the mortality of AECOPD patients during 6 months. The area under the curve for readmission (≤ 30 days) + DNI level (≥ 3.5%) was 0.753 (95% CI 0.676-0.830, P <  0.001) with a sensitivity of 73.7% and a specificity of 67.3%. CONCLUSION AECOPD patients who were readmitted ≤30 days and DNI ≥ 3.5% showed higher mortality. DNI level can be used as a predictor of prognosis in AECOPD patients who were readmitted after discharge.

中文翻译：

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中性粒细胞指数增量与慢性阻塞性肺疾病急性加重预后的关系。

背景技术在许多情况下，慢性阻塞性肺疾病（AECOPD）的急性加重与包括细菌或病毒在内的感染触发因素有关，肺炎是AECOPD住院的主要诱因，并且与不良结局密切相关。增量中性粒细胞指数（DNI）的增加可用于检测COPD肺炎患者。方法进行了一项回顾性队列研究，以调查因有或没有CAP的AECOPD出院后6个月内再次入院的患者的死亡率。我们根据血清DNI水平和再入院时间分析了累积生存率的差异。结果最后，在6个月内分别入组140例社区获得性肺炎（CAP）AECOPD患者和174例无CAP AECOPD患者。平均年龄为72.2±9.4岁，男性为2​​40例（76.4％）。根据再入院持续时间（≤30 vs> 30天）和DNI水平（<3.5 vs≥3.5％）比较累积生存率时，再次入院≤30天且DNI≥3.5％的AECOPD患者与其他组（P <0.001）。多变量分析显示再入院时间≤30天（HR 7.879，95％CI 4.554-13.632，P <0.001）；血清DNI水平（HR 1.086，95％CI 1.043-1.131，P <0.001）与AECOPD患者6个月的死亡率显着相关。再入院（≤30天）+ DNI水平（≥3.5％）的曲线下面积为0.753（95％CI 0.676-0.830，P <0.001），灵敏度为73.7％，特异性为67.3％。结论AECOPD患者入院≤30天且DNI≥3。5％显示较高的死亡率。在出院后再次入院的AECOPD患者中，DNI水平可以用作预后的预测指标。