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Geriatr Gerontol Int. 2018 Jul;18(7):1025-1030. doi: 10.1111/ggi.13293. Epub 2018 Mar 1.

Is anemia associated with cognitive impairment and delirium among older acute surgical patients?

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Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK.
Department of Medicine for the Elderly, Aberdeen Royal Infirmary, Aberdeen, UK.
Department of General Surgery, University Hospital of Wales, Cardiff, UK.
Department of General Surgery, North Bristol NHS Trust, Bristol, UK.
Department of General Surgery, Manchester Royal Infirmary, Manchester, UK.
Department of General Surgery, Royal Alexandra Hospital, Paisley, Greater Glasgow, UK.
University Hospital Llandough, Cardiff, UK.
Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.



The determinants of cognitive impairment and delirium during acute illness are poorly understood, despite being common among older people. Anemia is common in older people, and there is ongoing debate regarding the association between anemia, cognitive impairment and delirium, primarily in non-surgical patients.


Using data from the Older Persons Surgical Outcomes Collaboration 2013 and 2014 audit cycles, we examined the association between anemia and cognitive outcomes in patients aged ≥65 years admitted to five UK acute surgical units. On admission, the Confusion Assessment Method was carried out to detect delirium. Cognition was assessed using the Montreal Cognitive Assessment, and two levels of impairment were defined as Montreal Cognitive Assessment <26 and <20. Logistic regression models were constructed to examine these associations in all participants, and individuals aged ≥75 years only.


A total of 653 patients, with a median age of 76.5 years (interquartile range 73.0-80.0 years) and 53% women, were included. Statistically significant associations were found between anemia and age; polypharmacy; hyperglycemia; and hypoalbuminemia. There was no association between anemia and cognitive impairment or delirium. The adjusted odds ratios of cognitive impairment were 0.95 (95% CI 0.56-1.61) and 1.00 (95% CI 0.61-1.64) for the Montreal Cognitive Assessment <26 and <20, respectively. The adjusted odds ratio of delirium was 1.00 (95% CI 0.48-2.10) in patients with anemia compared with those without. Similar results were observed for the ≥75 years age group.


There was no association between anemia and cognitive outcomes among older people in this acute surgical setting. Considering the retrospective nature of the study and possible lack of power, findings should be taken with caution. Geriatr Gerontol Int 2018; 18: 1025-1030.


anemia; cognitive impairment; delirium; older surgical patients

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