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Recoverable Cognitive Dysfunction at Hospital Admission in Older Persons During Acute Illness
Article first published online: 11 SEP 2006
Journal of General Internal Medicine
Volume 21, Issue 12, pages 1276–1281, December 2006
How to Cite
Inouye, S. K., Zhang, Y., Han, L., Leo-Summers, L., Jones, R. and Marcantonio, E. (2006), Recoverable Cognitive Dysfunction at Hospital Admission in Older Persons During Acute Illness. Journal of General Internal Medicine, 21: 1276–1281. doi: 10.1111/j.1525-1497.2006.00613.x
- Issue published online: 11 SEP 2006
- Article first published online: 11 SEP 2006
- Manuscript received March 11, 2006Initial editorial decision May 10, 2006Final acceptance July 26, 2006
- cognitive impairment;
BACKGROUND: While acute illness and hospitalization represent pivotal events for older persons, their contribution to recoverable cognitive dysfunction (RCD) has not been well examined.
OBJECTIVE: Our goals were to estimate the frequency and degree of RCD in an older hospitalized cohort; to examine the relationship of RCD with delirium and dementia; and to determine 1-year cognitive outcomes.
DESIGN: Prospective cohort study.
PARTICIPANTS: Four hundred and sixty patients aged ≥70 years drawn from consecutive admissions to an academic hospital.
MEASUREMENTS: Patients underwent interviews daily during hospitalization and at 1 year. The primary outcome was RCD, defined as an admission Mini-Mental State Examination (MMSE) score that improved by 3 or more points by discharge.
RESULTS: Recoverable cognitive dysfunction occurred in 179 of 460 (39%) patients, with MMSE impairment at baseline ranging from 3 to 13 points (median=5.0 points). The majority of cases were not characteristic of either delirium or dementia, as 144 of 179 (80%) cases did not meet criteria for delirium, and 133 of 164 (81%) cases did not meet criteria for dementia at baseline. In multivariable analysis controlling for baseline MMSE level, 3 factors were predictive of RCD: higher educational level, preadmission functional impairment, and higher illness severity. At 1 year, further improvement in MMSE score occurred in 38 of 92 (41%) patients with RCD. Recoverable cognitive dysfunction was independently predictive of 1-year mortality with an adjusted odds ratio of 1.82 (95% confidence interval [95% CI] 1.03 to 3.20).
CONCLUSIONS: Acute illness is accompanied by a high rate of RCD that is neither characteristic of delirium or dementia. Our observations underscore the reversible nature of this cognitive dysfunction with continued improvement over the ensuing year, and highlight the potential clinical implications of this under-recognized phenomenon.