Objective: To determine the relationship between age and long-term cognitive impairment (CI) in a sample of intensive care unit survivors.
Design: Prospective cohort study.
Materials and Methods: In a medical ICU, we enrolled 276 mechanically ventilated patients and monitored them daily. Six-months after hospital discharge, 150 (54.3%) patients were alive, of whom 41 were tested with a neuropsychological battery. Tests scores were adjusted for age and education. Comparison of data between groups was done using Wilcoxson Two-Sample and Kruskal-Wallis Tests.
Results: 7 of 41 patients (17%) had possible CI prior to admission (according to standardized surrogate measures) and were excluded from our final analysis, leaving a sample size of 34. For purposes of comparison, the population was divided into 2 groups - geriatric (>60) (N= 11) and non-geriatric (<60) (N=23). The mean age for the geriatric group was 70.54+/-8.80 years (+/-S.D.), compared to 44.34+/-8.70 years (+/-S.D.) for the non-geriatric group. No statistically significant differences existed between groups on measures of baseline severity of illness (APACHE II: 24.18 vs. 25.17, p=0.81), depression (GDS-SF: 5.18 vs. 4.13, p=0.74), or quality of life (MCS-12: 40.58 vs. 45.41, p=0.31; PCS-12: 33.53 vs. 33.56, p=1.00). More neuropsychological dysfunction existed in the geriatric group. More than half of geriatric subjects (54%, N=6) displayed cognitive impairment of a severity consistent with mild dementia, compared with 21% of non-geriatric subjects (N=5). The geriatric group scored lower on cognitive measures and significantly lower on measures of mental status (MMSE: 25.36 vs. 28.47, p=0.04), visuo-construction (REY Complex Figure Copy: 23.22 vs. 30.50, p=0.01), and visual-memory (REY Complex Figure 30 Minute Recall: 7.00 vs. 12.82, p=0.05).
Conclusion: Significant numbers of critically ill patients display cognitive abnormalities following hospital discharge. Geriatric ICU survivors without pre-existing cognitive impairment experience greater degrees of cognitive impairment 6 months after hospital discharge than their non-geriatric counterparts. Cognitive deficits are particularly prevalent among geriatric patients on tests such as the REY Complex Figure Copy and Recall – which assess diverse cognitive domains and sample a range of abilities – and on measures of global cognitive ability such as the MMSE. The precise etiology of cognitive impairment in elderly subjects following critical illness is unknown. Future research is needed to determine the prevalence and incidence of cognitive impairment in geriatric ICU survivors and to address any modifiable risk factors in this population.
Back to S096 Interface of Medicine and Psychiatry
Back to The Eleventh International Congress