【Abstract】Objective To explore the dynamic changes of procalcitonin (PCT) and D-dimer (D-D) and investigate their values in the prognosis for severe pneumonia in the elderly patients. Methods A total of 78 elderly patients with severe pneumonia admitted in our hospital from January 2019 to June 2020 were recruited in this study. Their clinical outcome, PCT and D-D levels before treatment on the 3rd and 7th days of treatment, and immediately before out of ICU (or death) were recorded, and change rate of PCT (PCTc) and D-D (D-Dc) were calculated. Their score of Acute Physiology Age Chronic Health Evaluation Ⅱ (APACHE Ⅱ) were also recorded. Receiver operating characteristic (ROC) curve was drawn to assess the values of PCTc and D-Dc on the clinical outcome of the severe pneumonia patients. SPSS statistics 22.0 was used for statistical analysis. Data comparison between two groups was perfomed using χ² test, t test or Fisher exact test depending on date type. Results Among the 78 elderly patients, 31 cases (39.7%) were transferred out of ICU after treatment, and the other 47 (60.2%) patients died. The survival group had significantly younger age [(77.30±6.72) years] and lower APACHE Ⅱ score [(19.29±2.69) points] than the death group [(83.84±5.54) years, (21.02±2.72) points; P<0.05]. There were no obvious differences in PCT level between the survival group and the death group before and in 3 d after treatment (P>0.05). But the level was statistically lower in the survival group than the death group in 7 d after treatment and before transference from ICU or death [(2.57±0.65) vs (7.18±1.91) ng/ml, (0.62±0.25) vs (10.37±2.47) ng/ml; P<0.01]. Before and in 3 d after treatment, no significant difference was seen in D-D level between the 2 groups (P>0.05). Its level was in a decreasing trend in the survival group but in an increasing trend in the death group, and the former group had obviously lower level than the latter group in 7 d after treatment and transference from ICU or before death [(0.75±0.15) vs (3.78±0.85) mg/ml, (0.40±0.09) vs (4.89±0.69) mg/ml, P<0.001]. Statistical difference was seen in PCTc level between the 2 groups in 3 and 7 d after treatment and before out of ICU or death [5.56 (3.28,8.22) vs -3.17 (-4.55,0.00),53.73(49.12,58.93) vs -31.75(-40.91,-21.05),89.29(86.36,91.78) vs -96.86(-119.40,-68.00),all P<0.001]. The D-Dc level maintained at a high level and gradually turned to elevation with the condition better in the survival group. But the level differed from the 2 groups in 3 and 7 d after treatment and before out of ICU or death [0.00 (0.00,6.25) vs 0.00(-7.69,0.00),58.33(55.29,64.21) vs -95.24(-128.50,-60.87),77.22(74.29,83.64) vs -161.10(-218.70,-114.20); all P<0.001]. ROC curve analysis showed that PCTc, D-Dc and APACHEⅡ were of prognostic significances for the elderly with severe pneumonia [area under curve (AUC)=0.974,0.779, 0.337; P<0.05]. PCTc had an AUC of 0.974, a 95% confidence interval of 0.940 to 1.010, cutoff value of 0.658, a sensitivity of 93.5%, and a specificity of 97.9%. Conclusion PCTc and D-Dc could predict the clinical prognosis of elderly patients with severe pneumonia, and show good value in clinical application.

This work was supported by the Special Project for Clinical Research of Wu Jieping Medical Foundation in 2019 (320. 6750. 19089-2).