Alzheimer’s Dementia After Exposure to Anesthesia and Surgery in the Elderly

Abstract

Objective: The aim of this study was to determine whether surgery and anesthesia in the elderly may promote Alzheimer disease and related dementias (ADRD). Background: There is a substantial conflicting literature concerning the hypothesis that surgery and anesthesia promotes ADRD. Much of the literature is confounded by indications for surgery or has small sample size. This study examines elderly patients with appendicitis, a common condition that strikes mostly at random after controlling for some known associations. Methods: A matched natural experiment of patients undergoing appendectomy for appendicitis versus control patients without appendicitis using Medicare data from 2002 to 2017, examining 54,996 patients without previous diagnoses of ADRD, cognitive impairment, or neurological degeneration, who developed appendicitis between ages 68 through 77 years and underwent an appendectomy (the ''Appendectomy'' treated group), matching them 5:1 to 274,980 controls, examining the subsequent hazard for developing ADRD. Results: The hazard ratio (HR) for developing ADRD or death was lower in the Appendectomy group than controls: HR = 0.96 [95% confidence interval (CI) 0.94-0.98], P < 0.0001, (28.2% in Appendectomy vs 29.1% in controls, at 7.5 years). The HR for death was 0.97 (95% CI 0.95-0.99), P = 0.002, (22.7% vs 23.1% at 7.5 years). The HR for developing ADRD alone was 0.89 (95% CI 0.86-0.92), P < 0.0001, (7.6% in Appendectomy vs 8.6% in controls, at 7.5 years). No subgroup analyses found significantly elevated rates of ADRD in the Appendectomy group. Conclusion: In this natural experiment involving 329,976 elderly patients, exposure to appendectomy surgery and anesthesia did not increase the subsequent rate of ADRD.

Risk of Parkinson's disease after anaesthesia and surgery

“…EditordPostoperative delirium is characterised by acute and usually reversible cognitive disturbance with fluctuating changes in attention and level of consciousness, with an incidence of ~20% in older patients after major, non-emergent surgery. 1 It is recognised as a significant contributor to adverse outcomes in older hospitalised patients, as delirium is associated with prolonged hospitalisation, discharge to skilled care facilities, and persistent cognitive decline. 2,3 As surgical populations continue to age, the incidence of postoperative delirium and related complications will likely increase.…”

“…EditordWe previously examined the association between the exposure of surgery and anaesthesia for appendicitis and the subsequent development of Alzheimer's disease and related dementias (ADRD). 1,2 We chose to focus on appendicectomy because appendicitis appears to occur fairly randomly (acting as a natural experiment), and its sequelae are generally not long term, unlike other procedures possibly needed as a result of underlying illnesses that may affect long-term outcomes. Literature has suggested that there are common pathways of neurodegeneration in Parkinson's disease (PD) and ADRD.…”

“…The details of our matching techniques were published previously. 1 Briefly, for each of 55,000 older patients undergoing an appendicectomy for acute appendicitis, we matched five controls on 211 covariates reflecting health before the appendicectomy and followed these patients for up to 15 yr to determine if exposure to appendicectomy was associated with an increased rate of PD. Previous studies have suggested a 0.1e0.3% annual incidence rate of PD among older individuals in the USA (Supplementary Appendix 1, Section 7).…”

Academic Anesthesiology – Continuing to Provide Fulfillment and Opportunity

“…Retrospective studies on the risk for developing Alzheimer disease and related dementias (ADRD) after surgery with anesthesia have yielded conflicting results. A new study using a Medicare database compared this risk in nearly 55,000 patients aged 68 to 77 years without ADRD who required an appendectomy for appendicitis (treatment group) versus nearly 275,000 patients matched for age and multiple other factors who had no signs of appendicitis and no appendectomy prior to matching (control group) [1]. After 7.5 years follow-up, the treatment group actually had a lower rate of ADRD (7.6 versus 8.6 percent).…”

Stress Granules Modulate SYK to Cause Tau-Associated Neurocognitive Deterioration in 5XFAD Mouse After Anesthesia and Surgery

“…Besides, elderly surgical patients are more likely to have preexisting AD or be at risk for developing it (Işik, 2015). On the other hand, there are clinical studies that fail to support the association of anesthesia and surgery with AD (Avidan and Evers, 2011;Sprung et al, 2013Sprung et al, , 2020Aiello Bowles et al, 2016;Silber et al, 2020). However, some animal experiments have been reported where individuals with AD may develop cognitive impairment after anesthesia and surgery, but the mechanism is not clear (Zhang et al, 2017;Miao et al, 2018;Kim et al, 2021).…”