Perioperative platelet count in peripheral blood is associated with the early stage of PND after major orthopedic surgery: a prospective observational study

Abstract

Background: Perioperative neurocognitive disorders (PND) are common complications of major surgery among elderly patients, remarkably decreasing patients' life quality. Platelet count has been proved to be an essential factor in inflammation. However, as far as we know, the relationship between platelet count and PND is not clear yet in the orthopedic area. PND could be a long-term disease, which sometimes lasts for several years, and it is meaningful to find a biomarker of PND at the early stage. Thus, we designed this study to find out the association between perioperative platelet count and occurrence of PND, and determine whether preoperative platelet count could be a biomarker of the early stage of PND.

Methods: A prospective observational study was performed on the patients who would take total knee arthroplasty or total hip arthroplasty. Their peripheral platelets were counted by blood routine examination 1 day before and 3 days after the surgery. And we assessed their neurocognitive functions 1 day before and 3 days after the surgery. These data were recorded and analyzed to find out the relationship between platelet count and the occurrence of PND.

Results: Eventually, 70 patients finished the whole process, and 14 of them developed PND. The median preoperative platelet count in the PND group was significantly higher than that in the non-PND group (239 vs 168 × 10^9/L, p = 0.009). Preoperative platelet count was an independent risk factor for PND (odds ratio = 1.014, 95% confidence interval [CI] 1.000-1.027, P = 0.043) in the logistic multivariable regression, while the area under the curve of the receiver operating characteristic curve of the prediction model was 0.796 (95% CI 0.676-0.916).

Conclusions: The higher preoperative and postoperative level of platelet count in the peripheral blood were associated with the early stage of PND, and preoperative platelet count could be a potential predictor of the early stage of PND in patients undergoing major orthopedic surgeries.

Trial registration: Chinese Clinical Trial Registry: ChiCTR2000033001 , registration date: 17 May 2020.

Keywords: Biomarker; Elderly major orthopedic surgery; Perioperative neurocognitive disorders; Perioperative platelet count.

Fig. 1

Flow diagram of participants. The figure showed the whole process of patients’ inclusion and exclusion

Fig. 2

Receiver-operating characteristic (ROC) curves for preoperative platelet and postoperative platelet. The figure showed the ROC curves for preoperative platelet and postoperative platelet, whose area under the curve (AUC) were 0.728 and 0.754 respectively

Fig. 3

Receiver-operating characteristic (ROC) curve for prediction model of occurrence of PND. The figure showed the ROC curves for the prediction model of occurrence of PND, whose area under the curve (AUC) was 0.796