Low preoperative estimated glomerular filtration rate level is a risk factor for postoperative cognitive dysfunction in elderly undergoing elective total hip replacement: a prospective observational study.

Background: Postoperative cognitive dysfunction (POCD) is a postoperative complication of the central nervous system, especially in elderly patients. Growing evidence shows a close relationship between the kidney and cognition. This study aimed to evaluate the relationship between the subsequent risk of POCD and indicators related to the kidney.

Methods: A total of 93 eligible patients (≥65 years old) undergoing elective total hip replacement were enrolled. Before and 1 day after surgery, blood samples were collected from enrolled patients. Mini-Mental State Examination and Montreal Cognitive Assessment were conducted 1 day before surgery and 1 week after surgery or at discharge. The receiver operating characteristic curve was used to examine the predictive value of the estimated glomerular filtration rate (eGFR) for POCD. Univariate and multiple logistic regression models were used to analyze the risk factors of POCD.

Results: Thirty patients (32.26%) were assessed for POCD 1 week after surgery. The preoperative eGFR level in the POCD group was significantly lower than in the non-POCD group (P < 0.001). The area under the curve of eGFR was 0.739 (95% CI, 0.630-0.848; P < 0.001). The multivariable logistic regression analysis results showed that preoperative eGFR was independently associated with POCD (odds ratio = 0.965, 95% CI = 0.935-0.996, P = 0.028) after adjustment for mixed factors.

Conclusion: Low eGFR is associated with an increased risk of POCD in patients undergoing elective total hip replacement surgery. Low eGFR is an effective predictor of incident POCD.