Table 1.

Demographics

Variable	Sample as a whole N=821‡‡§§
Age at enrollment (years)	61 (51 – 71)
Caucasians N (%)	740 (90%)
Males N (%)	420 (51%)
Education (years)	12 (12 – 14)
AHRQ SES Index*	50 (48 – 53)
Charlson Comorbidity Index at enrollment†	2 (1 – 4)
APACHE APS at enrollment‡	21 (15 – 26)
Framingham Stroke Risk Profile at enrollment§	9 (6 – 14)
Apo E4 at enrollment¶
E2 / E2	0.5%
E2 / E3	10.1%
E2 / E4	2.4%
E3 / E3	61.1%
E3 / E4	22.6%
E4 / E4	3.3%
IQCODE at enrollment#	3 (3 - 3.1)
Clinical Frailty Scale at enrollment**	3 (3 – 5)
Delirium during study period	596 (73%)
Days of delirium in the hospital among everyone	1 (0 – 4)
Coma during study period	517 (63%)
Days of coma in the hospital among everyone	3 (2 – 6)
Days of severe sepsis in the ICU among everyone	572 (70%)
Mean modified SOFA score during ICU stay††	5 (4 – 7)
Intervals where O2 saturations < 90% during ICU stay	3 (0 – 12)

^*Agency for Healthcare Research and Quality Socioeconomic Status Index

^†The Charlson Comorbidity Index ranges from 0 to 33; for each increasing level of comorbidity there is a 2.3-fold increase in the 10-year risk of mortality.

^‡The Acute Physiology and Chronic Health Evaluation (APACHE) rates ICU mortality on a range of 0-71 using a combination of physiological variables and chronic health conditions. The Acute Physiology Score (APS) of the APACHE is a relative value scale applied to 12 physiologic variables used as a severity adjustment to diagnosis-related groups.

^§The Framingham Stroke Risk Profile integrates the effect of various vascular risk factors to predict the 10-year probability of incident stroke.

^¶Apolipoprotein E genotype

^#The Short Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) is a scale ranging from 1.0 to 5.0 where 5.0 indicates severe cognitive impairment.

^**Clinical Frailty Score ranges from 1 to 9 where 1 indicates very fit and 9 terminally ill.

^††The Sequential Organ Failure Assessment (SOFA) ranges from 0 to 24 with higher scores indicating more severe organ dysfunction. The modified SOFA score excludes the Glasgow Coma Scale since coma was included separately in our models.

^‡‡History of depression was missing in 38 participants and were not included in this table but included in the analysis using multiple imputation.

^§§Continuous variables are described as median values and interquartile range. Categorical variables are described using numbers and percentiles.