Recoverable cognitive dysfunction at hospital admission in older persons during acute illness.
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.


METHODS
Prospective cohort study.


METHODS
Four hundred and sixty patients aged > or =70 years drawn from consecutive admissions to an academic hospital.


METHODS
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.
Inouye
Sharon K
SK
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. Sharoninouye@hrca.harvard.edu
Zhang
Ying
Y
Han
Ling
L
Leo-Summers
Linda
L
Jones
Richard
R
Marcantonio
Edward
E
D000203:Activities of Daily Living; D000208:Acute Disease / Q000401:mortality / Q000523:psychology* / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000150:complications* / Q000453:epidemiology / Q000523:psychology*; D015331:Cohort Studies; D003693:Delirium / Q000150:complications / Q000453:epidemiology; D003704:Dementia / Q000150:complications / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D020127:Recovery of Function; D012720:Severity of Illness Index