The association between C-reactive protein and delirium in 710 acute elderly hospital admissions.
BACKGROUND
Delirium is a common neuropsychiatric syndrome associated with poor outcomes. Evidence supports a neuroinflammatory etiology, but the role of the inflammatory marker C-reactive protein (C-RP) remains unclear. We investigated the relationship between C-RP and delirium and its severity as well as interaction with medical diagnosis.


METHODS
From an existing database (710 patients over 70 years old admitted to a Medical Acute Admissions Unit) we analyzed data which included C-RP levels, delirium (using the Confusion Assessment Method), and other clinical and demographic factors. Primary diagnoses were grouped (cardiovascular, musculoskeletal, infection, metabolic, and other).


RESULTS
There was a strong association between elevated C-RP and delirium (t = 5.09; p < 0.001), independent of other potential risk factors for delirium (odds ratio (OR) = 1.32 (95% CI: 1.10-1.58) p = 0.003). There was no significant association between C-RP and delirium severity, and between C-RP and delirium in the populations with cardiovascular disease, infection upon admission, or from the metabolic group despite an OR of 2.24 (95% CI: 0.92-5.45). There was an association in the musculoskeletal group (OR 2.19 (95% CI: 1.19-4.02)).


CONCLUSIONS
There is an association between elevated C-RP and delirium. This is strongest in patients admitted with musculoskeletal disease but not in others, implying that C-RP is involved in the genesis of delirium in musculoskeletal disease, but that other factors or processes may be more important in those with cardiovascular disease or infection.
Centre for Mental Health, Imperial College London, London, UK.
C W
CW
Ritchie
Centre for Mental Health, Imperial College London, London, UK.
T H
TH
Newman
Marie Curie Palliative Care Research Unit, UCL Mental Health Sciences Unit, University College Medical School, Charles Bell House, London, UK.
B
B
Leurent
Marie Curie Palliative Care Research Unit, UCL Mental Health Sciences Unit, University College Medical School, Charles Bell House, London, UK.
E L
EL
Sampson
D000208:Acute Disease; D000368:Aged; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000150:complications; D003221:Confusion / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D003693:Delirium / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000523:psychology / Q000628:therapy; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007239:Infections / Q000150:complications; D008131:London; D008297:Male; D009140:Musculoskeletal Diseases / Q000150:complications; D009460:Neurologic Examination / Q000379:methods; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013223:Statistics as Topic
D015415:Biomarkers; D002097:C-Reactive Protein