Delirium Is an Important Predictor of Incident Dementia among Elderly Hip Fracture Patients

Background: Delirium is believed to constitute a risk factor for dementia, but previous research has failed to satisfactorily take account of the patients’ preexisting level of cognitive functioning. Methods: A prospective 6-month follow-up of 106 elderly hip fracture patients free from prefracture dementia. Delirium was assessed by the Confusion Assessment Method. Caregivers described the patients’ prefracture cognition by the Informant Questionnaire on Cognitive Decline in the Elderly, Short Form (IQCODE-SF). Cognition was measured after 6 months, using 5 validated cognitive tests. An expert panel assessed each case as to whether the diagnostic criteria for dementia according to the DSM-IV were fulfilled at baseline and after 6 months. Results: 29/106 patients (27%) developed delirium in the acute phase. In the delirious group, 11/29 (38%) fulfilled the criteria of dementia after 6 months, compared to 5/77 (7%) in the group without delirium (p < 0.001; χ 2 test). Delirium was the strongest predictor of dementia after 6 months (adjusted odds ratio: 10.5; 95% CI: 1.6–70.3). IQCODE-SF score was a nonsignificant risk factor for incident dementia. Conclusion: In hip fracture patients free from prefracture dementia, delirium constitutes the main predictor of dementia 6 months later, adjusted for prefracture cognitive decline measured by the IQCODE-SF.