[Application value of procalcitonin clearance rate on clinical outcome in patients with severe pneumonia]

Abstract

Objective: To investigate the changes in serum procalcitonin (PCT) in patients with severe pneumonia, and to analyze its value on evaluating the clinical outcome of patients with severe pneumonia.

Methods: A total of 58 patients with severe pneumonia aged over 18 years, and admitted to intensive care unit (ICU) of Zhuozhou City Hospital of Hebei Province from January 2017 to July 2018 were enrolled. The patients were divided into recovery group (the symptoms and signs of pneumonia disappeared or improved, and the X-ray chest films improved or did not make significant progress) and deterioration group (the symptoms and signs of pneumonia persisted or progressed, while X-ray chest radiography progressed, as well as serious complications such as involvement of other organ functions due to deterioration of pulmonary infection or septic shock) according to the therapeutic outcome. The serum PCT levels at 1, 3, 5, 7, 9 days after severe pneumonia diagnosed were recorded, and procalcitonin clearance rate (PCTc) was calculated. The acute physiology and chronic health evaluation II (APACHE II) score was estimated within 24 hours when severe pneumonia was diagnosed. Receiver operating characteristic (ROC) curve was drawn, and the area under ROC curve (AUC) was calculated to analyze the value of PCTc on evaluating the clinical outcome of patients with severe pneumonia.

Results: Among 58 patients, 33 (56.9%) had better outcome after active treatment (recovery group), and 25 (44.1%) had worse condition (deterioration group). There was no significant difference in PCT level at 1 day or 3 days between the recovery group and the deterioration group [μg/L: 5.05 (3.89, 7.61) vs. 5.29 (4.15, 7.46) at 1 day, 4.59 (4.02, 6.90) vs. 5.70 (4.59, 7.28) at 3 days, both P > 0.05]. With the prolongation of treatment time, serum PCT level was gradually decreased in the recovery group, while remained at higher level in the deterioration group, which was significantly lowered at 5, 7, 9 days in the recovery group as compared with that in the deterioration group [μg/L: 2.92 (2.09, 3.42) vs. 6.09 (3.24, 7.96) at 5 days, 1.94 (1.50, 2.07) vs. 7.65 (5.60, 10.52) at 7 days, 1.37 (0.91, 1.74) vs. 8.96 (6.09, 10.87) at 9 days, all P < 0.01]. PCTc at 3, 5, 7, 9 days in the recovery group were significantly higher than those in the deterioration group [15.10 (-17.80, 32.10)% vs. -1.53 (-20.80, 11.48)% at 3 days, 47.50 (30.25, 60.34)% vs. 6.25 (-14.58, 29.05)% at 5 days, 76.44 (53.18, 77.92)% vs. -11.20 (-66.75, -1.38)% at 7 days, 80.01 (59.86, 88.27)% vs. -38.15 (-99.38, -2.81)% at 9 days, all P < 0.05]. ROC curve analysis showed that PCTc at 3, 5, 7 and 9 days were valuable for evaluating the clinical outcome of patients with severe pneumonia, and 9-day PCTc had the greatest value, the AUC was 0.978 [95% confidence interval (95%CI) = 0.945-1.000, P = 0.000], which was higher than APACHE II (AUC = 0.442, 95%CI = 0.280-0.610, P = 0.392); when the best cut-off value of 9-day PCTc was 93.00%, its sensitivity was 99.0%, and specificity was 87.3%.

Conclusions: The PCT level of patients with severe pneumonia remained at a high level, which was related with the deterioration of the disease. PCTc, as an index to evaluate the clinical outcome of patients with severe pneumonia, has good application value.