[Dynamic changes of platelet count in first week and their predictive value for prognosis in septic shock patients]

To observe the dynamic changes of platelet counts in septic shock patients within first week, and to explore their predictive value for prognosis.

Retrospective analysis of clinical data of patients with septic shock admitted to the department of intensive care unit (ICU) of the First Affiliated Hospital of University of Science and Technology of China from January 2020 to December 2021 was conducted. The baseline data on gender, age and primary diseases, clinical indicators on infection site, pathogenic microbial type, acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA), laboratory indicators and the trend of platelet count (PLT) on day 1, 3, 5 and 7 admitting ICU and patients prognosis of in-hospital were collected. Binary Logistic regression was used to assess the independent risk factors of in-hospital death in septic shock patients. Receiver operator characteristic curve (ROC curve) was drawn to evaluate the predictive power of each index for in-hospital mortality.

A total of 193 patients with sepsis were enrolled. Among them, 73 patients died and 120 patients survived. Univariate analysis showed that the age, proportion of hypertension and respiratory system infection, APACHE II score, SOFA score and blood lactic acid (Lac) in the death group were significantly higher than those in the survival group, while the proportion of urinary system infection, white blood cell (WBC) and neutrophil (NEU) were significantly lower in the death group. Within 7 days after admitting ICU, the platelet (PLT) firstly decreased and then rebounded in the survival group, whereas it's showed a continuous downward trend in the death group. And the PLT count in both day 5 and 7 were significantly higher in the survival group compared with the dead group [×10⁹/L: 94.5 (54.0, 182.0) vs. 50.0 (30.5, 87.5), 135.0 (86.8, 205.8) vs. 46.0 (23.5, 71.5), all P < 0.05]. Multivariate binary Logistic regression analysis showed that age [odds ratio (OR) = 1.059, 95% confidence interval (95%CI) was 1.002-1.118], hypertension (OR = 6.108, 95%CI was 1.340-27.851), respiratory system infection (OR = 5.300, 95%CI was 1.116-25.118), APACHE II score (OR = 1.158, 95%CI was 1.054-1.273), SOFA score (OR = 1.494, 95%CI was 1.060-2.107) and PLT on day 7 after admitting ICU (OR = 0.926, 95%CI was 0.894-0.958) were independent risk factors for in-hospital prognosis in septic shock patients (all P < 0.05). ROC analysis showed that APACHE II score, SOFA score and PLT on day 7 after admitting ICU all had good predictive value for in-hospital prognosis in septic shock patients, and the area under the ROC curve (AUC) of PLT on day 7 (AUC = 0.899, 95%CI was 0.857-0.941) was significantly higher than that of APACHE II score (AUC = 0.748, 95%CI was 0.680-0.816), SOFA score (AUC = 0.767, 95%CI was 0.702-0.833).

Clinicians should pay close attention to the dynamic changes of platelet counts in septic shock patients, especially the platelet counts on day 7 after admitting ICU. And active intervention should be provided to improve the prognosis.