High risk of cognitive and functional decline after postoperative delirium. A three-year prospective study
Bickel H, Gradinger R, Kochs E, Förstl H;
Commented by , 31 Jul 2008
Aim of the study
To investigate the association of postoperative delirium with the outcomes of cognitive impairment, functional disability and death.
Methods
Follow-up over time of 200 patients aged ≥60 who had hip surgery, after pre and postoperative assessments during hospital stay.
Results
41/200 developed postoperative delirium. After 38 months 53.8% of surviving patients with postoperative delirium had cognitive impairment compared to 4.4% of those who did not. Logistic regression analysis adjusted for age, sex, medical comorbidity and preoperative cognitive performance revealed highly significant associations between delirium and cognitive impairment (OR=41.2; 95%CI=4.3-396.2), subjective memory decline (OR=6.2, 95%CI=1.5-25.8) and incident need for long-term care (OR=5.6; 95%CI=1.6-19.7).
Professor Gauthier's comments
The authors confirmed the clinical observations made by many geriatricians that postoperative delirium is a predictor of cognitive decline (usually caused by Alzheimer's disease) in later years. A randomized clinical trial published in the same issue of Dementia and Geriatric Cognitive Disorders by Kat et al. (ref. 1) also documented in a similar hip surgery population age ≥ 70 a higher mortality rate 30 month after discharge relative to controls (RR 1.6), a higher incidence of dementia (RR 1.9) and a higher rate of institutionalization (RR 1.8).
There are many reasons why these data are important. In addition to a higher rate of mortality during the postoperative delirium, there is a higher risk of dementia within 30 to 38 months. If and when therapeutic strategies to arrest progression of dementia (particularly of Alzheimer type) are available, patients who had postoperative delirium should be considered for early treatment.
It may also be possible to prevent postoperative delirium in persons found to be at risk in a postoperative assessment using cholinesterase inhibitors in low doses over 1 to 2 weeks prior to elective surgery; such a therapy needs to be established using a prospective placebo-controlled study.
In conclusion, a geriatric assessment should be routinely performed in elderly patients about to undergo elective orthopedic procedures in order to estimate the risk of postoperative delirium, intervene early if it does occur, and offer long term follow-up to monitor for cognitive impairment and functional decline. Hopefully in the near future more interventions will be possible in this "at risk" population.
References
1. Kat MG, Vreeswijk R, de Jonghe JF, van der Ploeg T, van Gool WA, Eikelenboom P, et al. Long-term cognitive outcome of delirium in elderly hip surgery patients. A prospective matched controlled study over two and a half years? Dementia and Geriatric Cognitive Disorders 2008; 26 (1); 1-8. [Epub 2008 Jul 9]