Application of blood PCT, IL-6 and AFR in evaluating the prognosis of elderly patients with severe pneumonia

Objective To evaluate the application of serum procalcitonin (PCT), interleukin 6 (IL-6) and albumin (ALB) /fibrinogen (FIB) ratio (AFR) for the prognosis of elderly patients with severe pneumonia (SP). Methods A total of 97 elderly patients with SP who were diagnosed and treated in the Second Affiliated Hospital of Xuzhou Medical University from January 2019 to May 2021 were enrolled. According to the prognosis of these patients within 28 days after admission, they were divided into two groups: a death group (n=33) and a survival group (n=64). Both groups were compared for their levels of PCT, IL-6, AFR, ALB, and FIB. A ROC curve was plotted to explore the value of combined detection of PCT, IL-6 and AFR in evaluating the prognosis of elderly SP patients. Results The death group showed higher levels of PCT, IL-6 and FIB, and lower levels of ALB and AFR than the survival group (P<0.05). According to the ROC curve, the AUC of PCT, IL-6, AFR, ALB, and FIB in predicting the prognosis of elderly SP patients was 0.807, 0.806, 0.754, 0.676, and 0.729, respectively (P<0.05). The sensitivity of PCT, IL-6, and AFR to predict the prognosis of elderly SP patients was 63.6%, 60.6%, and 87.5%, respectively. The specificity of PCT, IL-6, and AFR was 87.5%, 92.2%, and 54.5%, respectively. The cutoff of PCT, IL-6, and AFR was 6.16, 75.52, and 4.98, respectively. The AUC of combined PCT, IL-6 and AFR to predict the prognosis of elderly SP patients was 0.908, the sensitivity was 72.7%, and the specificity was 93.8%, which were significantly higher than those according to single indicators. Conclusions Increased blood PCT and IL-6 levels and decreased AFR levels are useful for evaluating the prognosis of elderly SP patients, and the combined detection has a higher predictive value.