 |
|
Delirium Predicts 12-Month Mortality
Jane McCusker, MD, DrPH;
Martin Cole, MD;
Michal Abrahamowicz, PhD;
Francois Primeau, MD;
Eric Belzile, MSc
Arch Intern Med. 2002;162:457-463.
ABSTRACT
| |
Background Delirium has not been found to be a significant predictor of postdischarge
mortality, but previous research has methodologic limitations including small
sample sizes and inadequate control of confounding. This study aimed to determine
the independent effects of presence of delirium, type of delirium (incident
vs prevalent), and severity of delirium symptoms on 12-month mortality among
older medical inpatients.
Methods A prospective, observational study of 2 cohorts of medical inpatients
was conducted with patients 65 years or older: 243 patients had prevalent
or incident delirium, and 118 controls had no delirium. Baseline measures
included presence of delirium and/or dementia, severity of delirium symptoms,
physical function, comorbidity, and physiological and clinical severity of
illness. Mortality during the 12 months after enrollment was analyzed with
the Cox proportional hazards model with adjustment for covariates.
Results The unadjusted hazard ratio of delirium with mortality was 3.44 (95%
confidence interval, 2.05-5.75); the adjusted hazard ratio was 2.11 (95% confidence
interval, 1.18-3.77). The effect of delirium was sustained over the entire
12-month period after adjustment for covariates and was stronger among patients
without dementia. Among patients with dementia, there was a weak, nonsignificant
effect of delirium on survival. After adjustment for covariates, mortality
did not differ between patients with incident and prevalent delirium, but
among patients with delirium without dementia, greater severity of delirium
symptoms was associated with higher mortality.
Conclusions Delirium is an independent marker for increased mortality among older
medical inpatients during the 12 months after hospital admission. It is a
particularly important prognostic marker among patients without dementia.
INTRODUCTION
DELIRIUM is a frequent phenomenon among older hospitalized patients
and has been found to be related to several adverse outcomes, including a
longer mean length of hospital stay, poor functional status and need for institutional
care, and mortality.1 With respect to mortality,
the evidence is not consistent2; controlled
studies have reported that delirium is associated with increased in-hospital
mortality.2-3 However, Inouye
et al4 controlled for age, sex, dementia, illness
severity, and functional status and found no significant elevation in in-hospital
or 3-month mortality. Several studies with up to 2 years of follow-up reported
no significant increase in postdischarge mortality.3, 5-7
A recent study with a median follow-up of 32.5 months reported a hazard ratio
(HR) of 1.71 (95% confidence interval [CI], 1.02-2.87) after adjustment for
comorbidity, dementia, frailty, age, sex, marital status, and institutional
residence.8 Nevertheless, these studies have
a number of methodologic limitations, including small sample sizes, often-limited
follow-up, and inadequate control of confounding factors such as dementia,
comorbidity, and severity of illness. Furthermore, it is not known whether
survival depends on the severity of the delirium, or on whether the delirium
is diagnosed at admission (prevalent delirium) or after admission (incident
delirium). The former is related to factors preceding hospital admission,
whereas the latter may be due to aspects of the care received in the hospital.
Also, little is known about whether the adverse consequences of delirium are
similar among demented and nondemented patients.
We undertook this study to determine the prognostic effect of delirium
on the outcome of older hospital medical inpatients during the 12 months after
admission. In this article, we report the independent effect of delirium,
adjusted for important confounding variables, on 12-month mortality and examine
the effects on mortality of type of delirium (incident vs prevalent), severity
of delirium symptoms, and presence of dementia.
METHODS
This prospective, observational, cohort study was conducted at a 400-bed,
university-affiliated, primary acute care hospital in Montreal, Quebec. We
compared 6- and 12-month outcomes in 2 cohorts: a delirium cohort with prevalent
or incident delirium detected during the first week of hospitalization, and
a control cohort without delirium. The study was conducted simultaneously
with a randomized controlled trial of the detection and treatment of delirium,
and a subgroup of the delirium cohort also participated in the trial.
ENROLLMENT OF SUBJECTS
A study nurse was responsible for patient screening and enrollment in
the 2 studies. Only patients 65 years or older who were admitted from the
emergency department to the medical services were included in the studies.
We excluded patients with a primary diagnosis of stroke, those admitted to
the oncology unit, those who spoke neither English nor French, and those admitted
to the intensive care unit or cardiac monitoring unit unless they were transferred
to a medical ward within 48 hours of admission. At enrollment and during the
first week of hospitalization, the nurse screened eligible patients for delirium
using the Short Portable Mental Status Questionnaire (SPMSQ), a 10-item questionnaire
that evaluates orientation, memory, and concentration,9
and review of the nursing notes. The nurse conducted the Confusion Assessment
Method (CAM)10 interview with subjects who
made 3 or more errors on the initial SPMSQ (indicating moderate to severe
cognitive impairment), subjects whose SPMSQ scores increased by at least 1
error from the first assessment, and subjects whose nursing notes indicated
possible symptoms of delirium. (The CAM is a structured interview that assesses
9 symptom domains of delirium specified in the Diagnostic
and Statistical Manual of Mental Disorders, Revised Third Edition.10)
Prevalent delirium was diagnosed if the criteria for probable or definite
delirium11 were met at enrollment; incident
delirium was diagnosed if the criteria were not met until after enrollment.
Controls were selected from patients who were screened for delirium and found
not to have it. To balance the distributions of age and prior cognitive impairment
among patients with delirium and controls, the sampling method took into account
each patient's age and initial SPMSQ score. Thus, controls were selected from
patients 70 years and older, and patients with SPMSQ scores of 3 or more were
oversampled.
Subjects with fewer than 5 errors on the SPMSQ gave informed consent
to participate in the study; those with 5 or more errors assented to participation,
and a relative provided written consent. The studies were approved by the
hospital's research ethics committee.
DATA COLLECTION AND MEASURES
Patients were assessed at enrollment by a research assistant, blind
to study group, who also interviewed a family member. Date of death during
follow-up was ascertained by the research assistant, who observed patients
at least weekly during their hospital stay, at 8 weeks after discharge, and
at 6 and 12 months after enrollment. Other baseline data were collected by
chart review by a nurse abstracter, blind to study group.
Dementia was assessed from the 16-item Informant Questionnaire on Cognitive
Decline in the Elderly (IQCODE),12 which has
high internal consistency and test-retest reliability12-14
in both its original 32-item form and in its 16-item short-form. Cutoff points
of 3.38,12-13 and 3.6 or higher15 have been used; we used an intermediate cutoff of
higher than 3.5 to define dementia.
We assessed the severity of delirium symptoms with the Delirium Index
(DI)16 based solely on patient observation,
without additional information from family members, nursing staff, or the
patient's medical chart. Only 7 of 9 symptom domains assessed on the CAM (disorders
of attention, thought, consciousness, orientation, memory, perception, and
psychomotor activity; acute onset and sleep-wake disturbance were excluded)
were rated on a 4-point scale (0, absent; 1, mild; 2, moderate; 3, severe);
the minimum and maximum possible scores, therefore, were 0 (no symptoms) and
21 (maximum severity), respectively. The DI has satisfactory interrater reliability
and concurrent criterion validity.17
We administered the Instrumental Activities of Daily Living (IADL) questionnaire
from the Older American Resources and Services (OARS) project17
to an informant and used it to assess premorbid function (prior to the current
illness but not more than 1 month before hospital admission). The scale score
range is 0 (completely dependent) to 16 (completely independent).
Three measures of illness burden and severity were used. Comorbidity
at admission was assessed by chart review using the Charlson Comorbidity Index,
a weighted index that takes into account the number and severity of comorbid
conditions.18 Acute physiologic severity of
illness was assessed with the Acute Physiology Score, derived from the APACHE
II scale.19 The index was coded by chart review
based on laboratory and clinical measures made on or before the date of enrollment.
Clinical severity of illness was assessed by the research nurse at enrollment.20-21 The scores ranged from 1 (minimal)
to 9 (most severe).
The International Classification of Diseases, Ninth
Revision, codes for primary discharge diagnoses were obtained from
the hospital administrative database. Demographic variables (age, sex, marital
status, and residence) were recorded in study baseline forms.
STATISTICAL METHODS
Analyses of mortality focused on 2 main questions: (1) the role of delirium
as an independent prognostic factor for death; and (2) identification of prognostic
factors for mortality in the delirium cohort. First, the 2 cohorts were compared
with respect to the baseline distribution of various prognostic risk factors,
using the independent groups t test and  2 test for quantitative and categorical variables, respectively. To
assess the impact of delirium on mortality, survival analytical techniques
were used to compare survival rates in delirium and control cohorts. Time
0 was defined as the study enrollment, and subjects were censored at the time
of loss to follow-up or at the end of the 12-month follow-up period, whichever
occurred earlier. We used the exponential model for the survival time distribution
to estimate the yearly mortality rates separately for each of the 2 cohorts.
Unadjusted analysis relied on the comparison of the Kaplan-Meier survival
curves and on the score test in the univariate Cox proportional hazards model,
which is equivalent to the log-rank test.22
To adjust the estimated effect of delirium on mortality for the possible
differences in the distribution of other risk factors in the 2 cohorts, we
used the multivariable Cox proportional hazards model with the following covariates
selected a priori: dementia, comorbidity, clinical severity, Acute Physiology
Score, admitting service (medicine vs geriatrics), and demographic variables.
In our primary analysis we did not adjust for premorbid IADL because
this measure is affected by the presence of dementia, a variable of interest
in this study. In our secondary analysis (not reported here) adjusting also
for IADL, we found that, as expected, the effect of delirium was essentially
unchanged, whereas the effect of dementia was slightly smaller. We also conducted
a secondary analysis (not reported here) in which we evaluated the effect
of considering primary discharge diagnosis as an additional covariate, grouped
into the 13 categories shown in Table 1. The inclusion of diagnosis had no effect on the magnitude of the
effect of delirium on survival.
|
|
|
|
Table 1. Selected Characteristics of Cohorts at Enrollment*
|
|
|
The proportional hazards assumption was verified using the regression
spline model–based likelihood ratio test.23
This allowed us to formally test whether the prognostic value of an initial
diagnosis of delirium changed during the 12-month follow-up. The importance
of such potential changes was then assessed based on a graph representing
the variation of the logarithm of the HR for the delirium vs control group
as a function of the follow-up duration. In addition, to further assess whether
the association between delirium diagnosis at baseline and mortality changed
with increasing follow-up duration, separate analyses were carried out for
3 time intervals: from inception to the end of the first month; from the second
month through the sixth month; and from the seventh month through the 12th
month. In each case, the analysis was restricted to subjects alive at the
beginning of the respective interval; and subjects who did not die until the
end of the interval were censored at that time. Using a similar approach,
separate analyses were also carried out for within-hospital and postdischarge
mortality.
To assess whether the impact of delirium on mortality depended on some
other patient characteristic(s), we evaluated first-order interactions between
delirium and each of the covariates by forcing all the covariates into the
multivariable Cox model and then selecting statistically significant interactions
through forward selection. Cutoff for entry into the model was P<.10.
Finally, to explore more fully the separate and joint effects of delirium
and dementia on mortality, subjects were classified into 4 categories of delirium/dementia:
(1) delirium alone; (2) delirium superimposed on dementia; (3) dementia alone;
and (4) no delirium or dementia. Using the group with no delirium or dementia
as the reference category, we estimated the relative risks associated with
each of the 3 other categories by including the corresponding dummy variables
in the Cox model.
Similar methods were used to identify prognostic factors for mortality
in the delirium cohort. The main focus of the analysis was on the assessment
of the role of delirium type and severity. Specifically, the following 3 delirium-related
variables were considered: (1) the mean of the first 2 DI scores (if obtained
during the first week of follow-up); (2) the binary indicator of definite
vs probable delirium (from the CAM); and (3) the binary indicator of prevalent
vs incident cases. Because these 3 variables were conceptually and statistically
related, we examined their effects in separate models, each time adjusting
for the covariates listed above, study group (inclusion in the intervention
or control group of the randomized trial), and for premorbid IADL.
RESULTS
During the study enrollment period, there were 4085 medical admissions,
of which 1552 (38.0%) were screened for delirium. The reasons for exclusion
were admission to oncology (n = 452), admission to intensive care or coronary
care units (n = 377), transfer to long-term care before screening (n = 332),
language barrier (n = 301), stroke (n = 289), missed or not sampled (n = 181),
refused screening (n = 164), previously enrolled in study (n = 127), transferred
or discharged (n = 113), communication problem (n = 105), residence outside
geographic area (n = 69), died before screening (n = 20), and other (n = 3).
Of the 1552 patients screened, 243 with a diagnosis of delirium and 118 controls
were enrolled in the study.
At enrollment, there were significant differences between the cohorts
with respect to demographic, clinical, and functional status measures (Table 1). Members of the delirium cohort
were more likely than controls to be male, more likely to have been admitted
to nongeriatric units, and, as expected, more severely impaired in all clinical
and functional status measures. They were also more likely to be demented.
These differences in the distribution of important prognostic factors made
it essential to adjust the comparison of mortality in the 2 cohorts for these
factors.
The cohorts did not differ with respect to age (owing in part to the
study design, which restricted age of controls to 70 years and older) and
several other characteristics not shown in Table 1 (marital status, level of education, type and length of
relationship to informant, visual or hearing impairment, and history of drug
or alcohol abuse). Dementia status was missing for 19 delirium cases and 20
controls because of failure to interview an informant.
IMPACT OF DELIRIUM ON MORTALITY
During the 12-month follow-up, 41.6% of the patients in the delirium
cohort and 14.4% of the controls died; 4.9% of the delirium cohort and 7.6%
of the controls withdrew from the study. Most withdrawals took place before
hospital discharge and were at the request of family members who did not want
the patients to be disturbed because of their medical illness. The estimated
yearly 12-month mortality rates were 63.3% for the delirium cohort and 17.4%
for controls (Figure 1). In the
delirium cohort, Kaplan-Meier survival decreased rapidly during the first
month after enrollment and then continued to decline but more slowly; the
survival curve declined more slowly in the control cohort (Figure 1).
|
|
|
|
Figure 1. Unadjusted Kaplan-Meier survival
curves of the 12-month mortality rate by study group.
|
|
|
Table 2 lists the univariate
and multivariate proportional hazards models for 12-month mortality. The unadjusted
association of delirium with mortality was very strong (HR, 3.44; 95% CI,
2.05-5.75). After adjustment for the differences between the distributions
of other prognostic factors in the 2 cohorts, the estimated effect of delirium
on mortality decreased but remained statistically significant (P = .01). Among patients with the same values for all other covariates,
delirium was independently associated with a 2-fold increase in mortality
during the 12-month follow-up (adjusted HR, 2.11; 95% CI, 1.18-3.77). Other
baseline variables significantly independently associated with higher mortality
in the final model included older age, not being currently married, and higher
scores on the comorbidity, clinical severity, and acute physiology scales;
male sex had a marginally nonsignificant effect (P
= .07).
|
|
|
|
Table 2. Results of Proportional Hazards Analyses of 1-Year Mortality*
|
|
|
The presence of dementia, on the other hand, was associated with a significant
protective effect, whereas patients whose dementia status was missing had
a nonsignificantly increased risk. There was an interaction between delirium
and dementia (P = .08), with a stronger effect of
delirium on mortality among patients without dementia (data not shown). To
further explore the effects of delirium and dementia on mortality, we compared
mortality among the 4 delirium/dementia groups (delirium alone; delirium superimposed
on dementia; dementia alone; and no delirium or dementia) while adjusting
for covariates. Using as the reference category patients with no delirium
or dementia, patients with delirium only are at a particularly high risk (HR,
3.77; 95% CI, 1.39-10.20). The HRs for patients with dementia and delirium
(1.96; 95% CI, 0.76-5.05) or with dementia alone (1.57; 95% CI, 0.52-4.71),
although elevated, did not differ significantly from the reference group.
Mortality was examined by time period using 2 different time groupings.
First, we investigated separately in-hospital mortality and postdischarge
mortality. Delirium was a significant predictor of postdischarge mortality
(HR, 2.16; 95% CI, 1.06-4.42). In the analysis of in-hospital mortality, there
were statistically significant interactions between delirium and comorbidity
(P = .01) and the Acute Physiology Score (P = .03); the effect of delirium was stronger among patients with lower
scores on these scales. Second, we investigated mortality in 3 time periods
following enrollment: the first month, months 2 through 6, and months 7 through
12. Delirium was associated with higher mortality in all 3 periods (Figure 2).
|
|
|
|
Figure 2. Assessing changes over time in
the adjusted effect of delirium on mortality. The solid line shows the logarithm
of the hazard ratio (log HR) expressing relative risks in the delirium cohort
compared with controls adjusted for all covariates included in the multivariable
model summarized in Table 2 as
a function of follow-up time. The dotted curves represent pointwise 95% confidence
intervals around the estimated log HR. The fact that the estimate is an almost
constant function of time indicates that the prognostic ability of the baseline
delirium remains stable over 12 months of follow-up.
|
|
|
The formal test of the changes over time in the effect of delirium on
mortality yielded a definitely nonsignificant result (P = .70), indicating that this effect remained fairly constant over
the 12 months of follow-up. Figure 2
provides additional support for this conclusion. The solid line in Figure 2 represents the estimated adjusted
effect of delirium in terms of logarithm of HR delirium/controls as a function
of follow-up time obtained using regression spline model.23
The almost perfect flatness of this estimate in spite of its potential flexibility
demonstrates that the effect of delirium diagnosed at study enrollment does
not show any tendency to decrease during the next 12 months.
Some other variables differed in their associations with in-hospital
vs postdischarge mortality. The Charlson Comorbidity Index was a significant
predictor of mortality in both time periods, while the Acute Physiology Score
as well as admission to a medical rather than geriatric ward predicted only
in-hospital mortality and not postdischarge mortality. On the other hand,
demographic factors such as male sex and unmarried status were associated
with higher risks of postdischarge mortality only. (The subgroup of patients
with missing dementia status had an elevated HR only for in-hospital mortality,
suggesting that this effect results from the failure to interview an informant
among patients who were imminently terminal.)
SURVIVAL ANALYSIS WITHIN THE DELIRIUM COHORT
We examined the following prognostic factors for mortality within the
delirium cohort: definite vs probable delirium (from the CAM findings), mean
DI score based on the first 2 DI measures during the first week, and prevalent
vs incident delirium. Because the first 2 measures were related to each other,
they were examined in separate models, each time adjusted for prevalent vs
incident delirium and for the dementia, comorbidity, clinical severity, Acute
Physiology Score, admitting service, and demographic variables (Table 3). In models that did not consider interactions, none of
these variables was significantly associated with mortality. However, there
was a significant interaction between the mean DI score and dementia: a higher
mean DI score was associated with higher mortality among patients without
dementia only (data not shown). There were no statistically significant interactions
of either definite/probable delirium or prevalent/incident delirium with dementia
or any of the other predictors (data not shown).
|
|
|
|
Table 3. Results of Proportional Hazards Analysis of 1-Year Mortality
in the Delirium Cohort*
|
|
|
COMMENT
The results of this study indicate a significantly higher 12-month mortality
rate among medical inpatients diagnosed with delirium than for controls without
delirium, even after adjustment for confounding by several measures of severity
and comorbidity, prior dementia, and other relevant factors. Notably, delirium
had a strong, sustained effect on mortality during the entire 12-month follow-up
period after adjustment for covariates. The effect of delirium was particularly
strong among patients without dementia. Among those with dementia, there was
a weak, nonsignificant effect of delirium on mortality.
Our study provides new evidence of the importance of delirium as a prognostic
indicator for mortality. Previous research has found an association only with
in-hospital mortality,2, 24 and
even then not in all studies4; postdischarge
mortality has not previously been associated with delirium.3, 5-7
The ability of our study to demonstrate a longer-term effect of delirium on
mortality may be related to our ability to recruit a large sample with excellent
follow-up and to control for other important characteristics, particularly
the presence of dementia, comorbidity, and severity of illness.
Of interest is the observation that all 3 measures of disease burden
and severity used in this study were significant independent predictors of
mortality. All these measures are known to predict mortality,17-18,20, 22
but seldom have all 3 been controlled simultaneously. This emphasizes the
importance of multiple measures of these constructs to avoid confounding.
In particular, the Charlson Comorbidity Index was a significant independent
predictor of mortality both during and after hospitalization, while the Acute
Physiology Score predicted only in-hospital and not postdischarge mortality.
Interestingly, primary discharge diagnosis did not confound the effect of
delirium on mortality and did not contribute further to our ability to predict
mortality in the presence of these other covariates.
Delirium during hospitalization seems to be a strong, independent marker
of high risk of mortality not just in the hospital, as indicated in previous
research, but for at least 12 months after admission. Furthermore, among patients
with delirium only, those with more severe delirium symptoms had the highest
mortality risk. We were unable to directly assess the effect on mortality
of the duration of delirium. Our results suggest that delirium has a particularly
strong effect on mortality among patients without preexisting dementia; the
HR in this group (compared with subjects with neither delirium nor dementia)
was 3.77 (95% CI, 1.39-10.20). In contrast, among patients with preexisting
dementia, there was a weaker, nonsignificant effect of delirium (and severity
of delirium symptoms) on mortality.
Three reasons for this discrepancy can be considered. First, delirium
among those with dementia may result from different pathological processes
compared with patients without dementia. The delirium in the former may be
primarily a manifestation of the underlying disease responsible for the dementia
and, therefore, of little additional prognostic importance. Second, delirium
may be harder to detect in those with dementia, leading to misclassification
and bias toward the null. Third, our instrument to identify dementia, the
IQCODE, may perform differently in patients with delirium. The IQCODE asks
informants to rate the behavioral change that took place among subjects from
over 5 years previously until immediately before the illness that led to hospital
admission. Informants may have confused the acute behavioral changes of delirium
with the longer-term changes associated with dementia. Further research is
needed in this complex area of measurement.
The results of this study have implications for the care of older medical
inpatients and for research in this population. First, delirium should be
considered a significant, serious problem in its own right and/or as a marker
of serious risk of mortality. The detection of delirium should prompt efforts
to identify and treat underlying medical problems. Previous research has demonstrated
consistently that in most cases, delirium is not detected in hospital settings.25 A randomized trial of the systematic detection and
management of delirium by a physician-nurse team, conducted by members of
our group in conjunction with the present study, found no overall significant
benefit on mortality or other outcomes.26 However,
there was a potentially clinically important, although statistically nonsignificant,
benefit of the intervention among patients without dementia. Further research
is warranted in this high-risk population to identify potentially modifiable
factors leading to death. It is also important to investigate postdischarge
interventions because the increased mortality risk in these patients seems
to be sustained well beyond hospital discharge.
AUTHOR INFORMATION
Accepted for publication July 2, 2001.
This research was supported by grants from the Medical Research Council
of Canada, Ottawa, Ontario (MA14709), the Fonds de la Recherche en Santé
du Québec, Montreal, Quebec (980892), and St Mary's Hospital Center,
Montreal (SMH9627). Dr Abrahamowicz is a Scientist of the Canadian Institutes
of Health Research, Ottawa, Ontario, and receives financial support from them.
Corresponding author and reprints: Jane McCusker, MD, DrPH, Department
of Clinical Epidemiology and Community Studies, St Mary's Hospital Center,
3830 Lacombe Ave, Room 2508, Montreal, Quebec, Canada H3T 1M5 (e-mail: jane.mccusker{at}mcgill.qc.ca).
From the Departments of Clinical Epidemiology and Community Studies
(Dr McCusker and Mr Belzile) and Psychiatry (Drs Cole and Primeau), St Mary's
Hospital Center; Epidemiology and Biostatistics (Drs McCusker and Abrahamowicz)
and Psychiatry (Drs Cole and Primeau), McGill University; and the Division
of Clinical Epidemiology, Montreal General Hospital (Dr Abrahamowicz), Montreal,
Quebec.
REFERENCES
| |
1. Cole M, Primeau F. Prognosis of delirium in elderly hospital patients. CMAJ. 1993;149:41-46.
ABSTRACT
2. Rabins PV, Folstein MF. Delirium and dementia: diagnostic criteria and fatality rates. Br J Psychiatry. 1982;140:149-153.
FREE FULL TEXT
3. Pompei P, Foreman M, Rudberg MA, Inouye SK, Braund V, Cassel CK. Delirium in hospitalized older persons: outcomes and predictors. J Am Geriatr Soc. 1994;42:809-815.
ISI
| PUBMED
4. Inouye S, Rushing J, Foreman M, Palmer R, Pompei P. Does delirium contribute to poor hospital outcomes? a three-site epidemiologic
study. J Gen Intern Med. 1998;13:234-242.
FULL TEXT
|
ISI
| PUBMED
5. Francis J, Martin D, Kapoor WN. A prospective study of delirium in hospitalized elderly. JAMA. 1990;263:1097-1101.
FREE FULL TEXT
6. Francis J, Kapoor WN. Prognosis after hospital discharge of older medical patients with delirium. J Am Geriatr Soc. 1992;40:601-606.
ISI
| PUBMED
7. O'Keeffe S, Lavan J. The prognostic significance of delirium in older hospital patients. J Am Geriatr Soc. 1997;45:174-178.
ISI
| PUBMED
8. Rockwood K, Cosway S, Carver D, Jarrett P, Stadnyk K, Fisk J. The risk of dementia and death after delirium. Age Ageing. 1999;28:551-556.
FREE FULL TEXT
9. Pfeiffer E. A short portable mental status questionnaire for the assessment of
organic brain deficit in elderly patients. J Am Geriatr Soc. 1975;23:433-441.
ISI
| PUBMED
10. Inouye S, VanDyck C, Alessi C, Balkin S, Siegal A, Horwitz R. Clarifying confusion: the confusion assessment method—a new method
for detection of delirium. Ann Intern Med. 1990;113:941-948.
11. Lewis LM, Miller DK, Morley JE, Nork MJ, Lasater LC. Unrecognized delirium in ED geriatric patients. Am J Emerg Med. 1995;13:142-145.
FULL TEXT
|
ISI
| PUBMED
12. Jorm A. A short form of the Informant Questionnaire on Cognitive Decline in
the Elderly (IQCODE): development and cross-validation. Psychol Med. 1994;24:145-153.
ISI
| PUBMED
13. Jorm FA, Broe AG, Creasey H, et al. Further data on the validity of the Informant Questionnaire on Cognitive
Decline in the Elderly (IQCODE). Int J Geriatr Psychiatry. 1996;11:131-139.
FULL TEXT
|
ISI
14. Jorm A, Christensen H, Henderson A, Jacomb PA, Korten A, Mackinnon A. Informant ratings of cognitive decline of elderly people: relationship
to longitudinal change on cognitive tests. Age Ageing. 1996;25:125-129.
FREE FULL TEXT
15. Law S, Wolfson C. Validation of a French version of an informant-based questionnaire
as a screening test for Alzheimer's disease. Br J Psychiatry. 1995;167:541-544.
FREE FULL TEXT
16. McCusker J, Cole M, Bellavance F, Primeau F. Reliability and validity of a new measure of severity of delirium. Int Psychogeriatr. 1998;10:421-433.
FULL TEXT
| PUBMED
17. Fillenbaum G. Multidimensional Functional Assessment: The OARS
Methodology—A Manual. Durham, NC: Duke University Center for the Study of Aging and Human
Development; 1978.
18. Charlson M, Pompei P, Ales K, MacKenzie R. A new method of classifying prognostic comorbidity in longitudinal
studies: development and validation. J Chronic Dis. 1987;40:373-383.
FULL TEXT
|
ISI
| PUBMED
19. Knaus W, Draper E, Wagner D, Zimmerman J. APACHE II: a severity of disease classification system. Crit Care Med. 1985;13:818-829.
ISI
| PUBMED
20. Charlson M, Sax F, MacKenzie R, Fields S, Braham R, Douglas R. Assessing illness severity: does clinical judgment work? J Chronic Dis. 1986;39:439-452.
FULL TEXT
|
ISI
| PUBMED
21. Inouye S, Viscoli C, Horwitz R, Hurst L, Tinetti M. A predictive model for delirium in hospitalized elderly medical patients
based on admission characteristics. Ann Intern Med. 1993;119:474-481.
FREE FULL TEXT
22. Cox D. Regression models and life tables (with discussion). J R Stat Soc. 1972;34:187-220.
23. Abrahamowicz M, MacKenzie T, Esdaile J. Time-dependent HR: modeling and hypothesis testing with application
in lupus arthritis. J Am Stat Assoc. 1996;81:1432-1439.
FULL TEXT
24. Pompei P, Foreman M, Rudberg MA, Inouye SK, Braund V, Cassel CK. Delirium in hospitalized older persons: outcomes and predictors. J Am Geriatr Soc. 1994;42:809-815.
25. Thomas RI, Cameron DJ, Fahs MC. A prospective study of delirium and prolonged hospital stay: exploratory
study. Arch Gen Psychiatry. 1988;45:937-940.
FREE FULL TEXT
26. Cole M, McCusker J, Bellavance F, et al. Randomized trial of systematic detection and treatment of delirium
in older hospitalized medical patients. CMAJ. In press.
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati
What's this?
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
|
Predicting the onset of delirium in the post-operative patient
Noimark
Age Ageing 2009;38:368-373.
ABSTRACT
| FULL TEXT
Delirium accelerates cognitive decline in Alzheimer disease
Fong et al.
Neurology 2009;72:1570-1575.
ABSTRACT
| FULL TEXT
Falls in the General Hospital: Association With Delirium, Advanced Age, and Specific Surgical Procedures
Lakatos et al.
Psychosomatics 2009;50:218-226.
ABSTRACT
| FULL TEXT
Impact of Delirium on Short-Term Mortality in Elderly Inpatients: A Prospective Cohort Study
Gonzalez et al.
Psychosomatics 2009;50:234-238.
ABSTRACT
| FULL TEXT
Assessing Delirium in the Intensive Care Unit
Sona
Crit Care Nurse 2009;29:103-105.
FULL TEXT
Trajectories of Life-Space Mobility After Hospitalization
Brown et al.
ANN INTERN MED 2009;150:372-378.
ABSTRACT
| FULL TEXT
Persistent delirium in older hospital patients: a systematic review of frequency and prognosis
Cole et al.
Age Ageing 2009;38:19-26.
ABSTRACT
| FULL TEXT
Postoperative Delirium
Fricchione et al.
Am. J. Psychiatry 2008;165:803-812.
FULL TEXT
Differing management of people with advanced cancer and delirium by four sub-specialties
Agar et al.
Palliat Med 2008;22:633-640.
ABSTRACT
Multicomponent Geriatric Intervention for Elderly Inpatients With Delirium: Effects on Costs and Health-Related Quality of Life
Pitkala et al.
Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2008;63:56-61.
ABSTRACT
| FULL TEXT
Delirium Superimposed on Dementia Predicts 12-Month Survival in Elderly Patients Discharged From a Postacute Rehabilitation Facility
Bellelli et al.
Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2007;62:1306-1309.
ABSTRACT
| FULL TEXT
Associations of delirium with in-hospital and in 6-months mortality in elderly medical inpatients
Adamis et al.
Age Ageing 2007;36:644-649.
ABSTRACT
| FULL TEXT
Delirium post-stroke
McManus et al.
Age Ageing 2007;36:613-618.
ABSTRACT
| FULL TEXT
Symptom Profile of Delirium in Older People With and Without Dementia
Edlund et al.
J Geriatr Psychiatry Neurol 2007;20:166-171.
ABSTRACT
An Exploratory Study of Diagnostic Criteria for Delirium in Older Medical Inpatients
Cole et al.
J. Neuropsychiatry Clin. Neurosi. 2007;19:151-156.
ABSTRACT
| FULL TEXT
Delirium in older patients admitted to general internal medicine.
Edlund et al.
J Geriatr Psychiatry Neurol 2006;19:83-90.
ABSTRACT
Multicomponent geriatric intervention for elderly inpatients with delirium: a randomized, controlled trial.
Pitkala et al.
Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2006;61:176-181.
ABSTRACT
| FULL TEXT
Can Olanzapine Cause Delirium in the Elderly?
Lim et al.
The Annals of Pharmacotherapy 2006;40:135-138.
ABSTRACT
| FULL TEXT
A decrease of >=2 points on the Mini-Mental State Examination was the best determinant of delirium in elderly patients admitted to hospital
Fields
Evid. Based Med. 2005;10:149-149.
FULL TEXT
Premature Death Associated With Delirium at 1-Year Follow-up
Leslie et al.
Arch Intern Med 2005;165:1657-1662.
ABSTRACT
| FULL TEXT
Preventing delirium in older people
Anderson
Br Med Bull 2005;73-74:25-34.
ABSTRACT
| FULL TEXT
Delirium in Elderly Patients
Cole
Focus 2005;3:320-332.
ABSTRACT
| FULL TEXT
Delirium From the COX-2 Inhibitor Refecoxib
Muralee et al.
Psychosomatics 2004;45:361-363.
FULL TEXT
Delirium as a Predictor of Mortality in Mechanically Ventilated Patients in the Intensive Care Unit
Ely et al.
JAMA 2004;291:1753-1762.
ABSTRACT
| FULL TEXT
Delirium and Dementia
Ajilore and Kumar
Focus 2004;2:210-220.
ABSTRACT
| FULL TEXT
Delirium: A Call to Improve Current Standards of Care
Flaherty and Morley
Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2004;59:M341-M343.
FULL TEXT
Accuracy of Referring Psychiatric Diagnosis on a Consultation-Liaison Service
Dilts et al.
Psychosomatics 2003;44:407-411.
ABSTRACT
| FULL TEXT
Studying delirium
Cole and McCusker
CMAJ 2003;168:541-542.
FULL TEXT
Other articles noted
Evid. Based Ment. Health 2002;5:104-104.
FULL TEXT
|
