关键词: 老年, 社区获得性肺炎, 中性粒细胞CD64指数, 营养不良, 预后

Abstract: Objective　To investigate the prognostic value of neutrophil CD64 index combined with Mini Nutrition Assessment Short Form (MNA-SF) score in elderly patients with community-acquired pneumonia. Methods　A total of 116 patients over 60 years old who were hospitalized and diagnosed with community-acquired pneumonia in Department of Geriatric Medicine, The Second People's Hospital of Lianyungang from January 2020 to December 2021 were selected as the research objects. The MNA-SF nutritional score on admission and C-reactive protein (CRP) and neutrophil CD64 index on the first and third day after admission were recorded. According to the severity of pneumonia, the patients were divided into a severe pneumonia group and a common pneumonia group. In the severe pneumonia group, there were 26 males and 17 females, with an age of (84.02±6.86) years old; there were 41 males and 32 females in the common pneumonia group, with an age of (81.89±8.92) years old. At the same time, they were divided into a death group and a survival group according to the 28-day clinical outcome. There were 11 males and 11 females in the death group, with an age of (85.64±6.18) years old; there were 56 males and 38 females in the survival group, with an age of (81.99±8.54) years old. t test, rank sum test, and chi-square test were used. Results　There were statistically significant differences in the Charlson comorbidibility index [(3.47±1.14) vs. (2.19±1.15)], MNA-SF score [(6.33±2.00) vs. (8.74±2.87)], and white blood cell count (WBC) [(13.64±5.89) ×10⁹/L vs. (9.67±4.08) ×10⁹/L, (11.91±5.76) ×10⁹/L vs. (7.98±2.38) ×10⁹/L], CRP [107.14 (72.06, 165.27) mg/L vs. 50.87 (22.98, 91.13) mg/L, 67.93 (36.99, 111.20) mg/L vs. 16.80 (11.40, 26.06) mg/L], and CD64 index [3.11 (1.78, 5.40) vs. 1.27 (1.14, 2.33), 1.80 (1.14, 3.15) vs. 1.03 (0.69, 1.30)] on the first and third day after admission between the severe pneumonia group and the common pneumonia group (all P<0.05). Among the 116 cases, 22 cases died, with a mortality rate of 18.97%. Compared with those in the survival group, the death group had a higher Charlson comorbidity index and a lower MNA-SF score, with statistically significant differences between the two groups (both P<0.05); there were statistically significant differences in the WBC, CRP, and CD64 index on the first and third day after admission between the two groups (all P<0.05). The areas under the curve (AUC) of CRP, CD64 index, and WBC in predicting prognosis were higher on the third day than those on the first day. The AUC of CRP d1+CD64 index d1+WBC d1+MNA-SF score in predicting prognosis was 0.909, the sensitivity was 95.5%, and the specificity was 72.9%; the AUC of CRP d3+CD64 index d3+WBC d3+MNA-SF score was 0.963, the sensitivity was 95.5%, and the specificity was 85.9%. Logistic regression analysis showed that malnutrition, CRP d3, and CD64 index d1 were risk factors for death in elderly patients with community-acquired pneumonia (all P<0.05). The survival curve (K-M curve) analysis showed that the 28-day survival rate in patients with CD64 index d1 <1.55 was significantly higher than that in patients with CD64 index d1 ≥1.55, and the 28-day survival rate of the two groups was statistically significant (96.55% vs. 65.52%, χ²=18.027, P<0.001). Conclusion　Neutrophil CD64 index combined with MNA-SF nutritional score can guide the clinical treatment and predict the prognosis of elderly patients with community-acquired pneumonia.

Key words: Old age, Community-acquired pneumonia, Neutrophil CD64 index, Malnutrition, Prognosis