Retrospective analysis cognitive function changes in elderly depressive patients after gastrointestinal tumor surgery and exploration of cholinergic mechanism

Abstract

BACKGROUND

Gastrointestinal tumors are among the most common malignant tumors in older people. Surgical treatment for these tumors is characterized by extensive scope, severe trauma, and prolonged during of anesthesia, and it is considered to pose a high risk for post-operative cognitive dysfunction (POCD).

AIM

To retrospectively analyze the medical records of older patients with depression who developed POCD after surgery for a gastrointestinal tumor.

METHODS

A total of 95 older patients with depression who underwent surgery. For a gastrointestinal tumor at the Second Affiliated Hospital of Soochow University between January 2021 and December 2024, were retrospectively selected. Patients were assigned to the POCD group or the non-POCD group based on the post-surgical presence of POCD. Indicators, including general data, peri-operative data, depressive status, cognitive function, and laboratory test results, were collected. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors for POCD, and a mediating effect model was used to explore the mediating role of cholinergic function in depression and POCD.

RESULTS

The incidence of POCD at seven days post-surgery was 36.84%. Univariate and multivariate logistic regression analyses showed that advanced age, high pre-operative Hamilton Depression Rating Scale (HAMD) score, lengthy duration of surgery, intra-operative administration of anticholinergic drugs, and high post-operative interleukin-6 (IL-6) change rate, were independent risk factors for POCD. Mediating effect analysis revealed that the pre-operative HAMD score had a significant positive predictive effect on post-operative IL-6, and post-operative IL-6 had a significant negative predictive effect on post-operative Montreal Cognitive Assessment (MoCA) score; the direct effect of HAMD on MoCA and the indirect effect mediated by IL-6 were significant, with the indirect effect accounting for 19.7% of the total effect. Additionally, the pre-operative HAMD score had a significant negative predictive effect on the post-operative cholinesterase (CHE) level, and the post-operative CHE level had a significant positive predictive effect on the post-operative MoCA score; the indirect effect was significant, accounting for 17.2% of the total effect.

CONCLUSION

The incidence of POCD is relatively high in older patients with depression after surgery for a gastrointestinal tumor. Advanced age, pre-operative depression severity, surgical trauma stress, and intra-operative administration of anticholinergic drugs were independent risk factors for POCD. The severity of pre-operative depression can upregulate the systemic inflammatory response, leading to cholinergic system dysfunction and increased risk of POCD.

Keywords: Post-operative cognitive dysfunction; Older people with depression; Gastrointestinal tumor; Cholinergic system; Retrospective study

Core Tip: Data from 95 older patients with depression who had gastrointestinal tumor surgery, were retrospectively analyzed, and there was an incidence of post-operative cognitive dysfunction (POCD) of 36.84%, seven days post-operatively. Advanced age, high pre-operative Hamilton Depression Rating Scale score, long duration of surgery, intra-operative anticholinergics, and high post-operative interleukin-6 (IL-6) change rate were independent risk factors for POCD. Mechanistically, pre-operative depression exacerbated systemic inflammation (via IL-6) and impaired cholinergic function (via reduced cholinesterase), jointly increasing the risk of POCD, with the two mediating effects accounting for 19.7% and 17.2% of the total effect, respectively. These findings provide a basis for the targeted prevention of POCD.