Delirium in an acute geriatric unit: clinical aspects

Archives of Gerontology and Geriatrics

28 (1999) 37–44

Delirium in an acute geriatric unit:clinical aspects

Jacob Feldman, Abraham Yaretzky *, Naila Kaizimov,Peter Alterman, Carola Vigder

The Geriatric Department, Sapir Medical Center, Meir Hospital, Kfar-Saba 44281, Israel

Received 8 June 1998; received in revised form 13 August 1998; accepted 23 August 1998

Abstract

Delirium is a common event in geriatric hospitalized patients. A prospective study wasperformed in order to characterize predictors, features and outcome in an acute geriatric careunit in a general hospital in Israel. The tools used to detect delirium were the ConfusionAssessment Method (CAM) and the Delirium Rating Scale (DRS), supported by clinicalobservation by an experienced geriatrician. Results showed an occurrence of 18%; riskfactors were polypharmacy and poor nutritional status. Age, education, ethnic origin,pre-morbid cognition and ADL status did not show any statistical correlation with theoccurrence of delirium. Delirious patients experienced longer hospital stays, more complica-tions, high mortality rate, cognitive and functional decline. It is very difficult to prove thecorrelation between reduction of brain reserve and appearance of delirium, but as we haveobserved in other systems (cardiovascular, renal, etc.), it seems reasonable to presume thatthe same mechanism is involved in cognitive function. Our conclusions are that the diagnosisof delirium may be misleading by a psychiatric overwhelming presentation, and should beconsidered not as a transient event, but as a marker for cognitive and functional decline inthe future, and therefore these patients should be looked after once discharged. © 1999Elsevier Science Ireland Ltd. All rights reserved.

Keywords: Delirium; Geriatric patients; Clinical aspects of delirium

* Corresponding author. Tel.: +972 9 7471003; fax: +972 9 7408610.

0167-4943/99/$ - see front matter © 1999 Elsevier Science Ireland Ltd. All rights reserved.

PII S0167-4943(98)00124-1

J. Feldman et al. / Arch. Gerontol. Geriatr. 28 (1999) 37–4438

1. Introduction

Delirium is an acute confusional disorder involving cognitive and affectiveaspects (American Psychiatric Association, 1994). Its prevalence among hospital-ized patients reaches 10–50% (Gillick et al., 1982; Francis et al., 1990).

This common disorder in the elderly is often misdiagnosed (Armstrong et al.,1997). The psychiatric features of delirium (defined in DSM IV) may mask itsunderlying causes and therefore delay an appropriate diagnosis and treatment,resulting in a high mortality rate, severe morbidity and significant functionaldecline. We undertook a prospective study aimed at isolating the characteristics ofthis common event in an acute geriatric unit in Israel.

2. Patients and methods

2.1. Subjects

We studied 61 patients, 70 or more years of age, admitted consecutively over a6-month period, to a 30-bed acute care geriatric unit within a university teachinghospital. Exclusion criteria were: patients who were not admitted to the geriatricunit on the day of admission to the hospital, patients admitted electively forinvestigation or rehabilitation, patients with aphasia or deafness, patients who wereexpected to remain in the hospital for less than 48 h, patients with moribundconditions and patients who were not assessed by a study doctor within 48 h ofadmission. Only the first admission of a patient within the study period wasincluded.

2.2. Clinical e6aluation

For every patient included, information about racial origin, education, place ofabode (community or nursing home), previous cognitive status and past medicalhistory including previous hospitalizations was sought from family members,caregivers and the general practitioner, and by inspection of previous medical andnursing notes.

Drugs used by patients prior to hospitalization were recorded, especially high riskgroup of medications, including benzodiazepine, anticholinergics, antidepressantsand antiparkinsonians.

All patients were examined for symptoms of delirium within 48 h of admission byan experienced geriatrician. Subsequently, all participants were monitored every 48h for at least the first 14 days of their stay, and were then monitored on anintermittent basis until discharge or death.

To maximize detection of symptoms of delirium we collected data by twomethods: the Confusion Assessment Method (CAM) (Inouye et al., 1990) and theDelirium Rating Scale (DRS) (Trzepacz et al., 1988). Only those patients whorespond to all three methods defining delirium (examination by an experiencedgeriatrician; CAM; DRS) were included in the study.

J. Feldman et al. / Arch. Gerontol. Geriatr. 28 (1999) 37–44 39

Assessment also included Mini-Mental-State-Examination (MMSE) (Folstein etal., 1975) and functional status at discharge. Functional status was assessed onadmission and on discharge using the Katz activities of daily living (ADL) scale(Katz and Akpom, 1976).

Finally we mention the discharge disposition among the community dwellingsample.

2.3. Nutritional assessment

Laboratory results (albumin, cholesterol, lymphocyte count, ferrum and folicacid values) reflecting nutritional status of patients were collected. Percent of weightloss during 6 months prior to hospitalization was also recorded.

2.4. Hospital acquired complications

Falls, pressure sores and urinary incontinence were recorded according tostandardized criteria and were identified on the basis of interviews with anexperienced nurse.

2.5. Statistics

T-test was used to compare continuous variables in patients with and withoutdelirium. Chi-square test was used to compare frequencies of discrete variables.One-way analysis of variance with repeated measures was used for two variables—MMSE and cognition.

3. Results and discussion

Characteristics of delirious subjects and non-delirious controls are shown inTables 1–3. Of the 61 study participants delirium occurred in 11 (18%). There wasno statistically significant difference between the two groups concerning age,education or ethnic origin. Delirious patients used more medications (especiallyfrom the high risk drugs), their hospital stay was longer and they had moreconcurrent diseases. Cognition prior to hospitalization was similar in both groupsbut MMSE on discharge was lower in delirious patients. This group of patients hadmore hospitalizations during the year prior to the study enrolment. Deliriouspatients experienced more in-hospital complications, and a higher mortality rate.All delirious patients (11) were admitted to the hospital from the community (Table4), and three of them died. The percent of delirious patients among those who wereindependent on ADL prior to hospitalization was lower compared to dependentpatients, but without a statistically significant difference (Table 5).

Nutritional parameters are shown in Table 6. Albumin levels were significantlylower in the delirious group. Weight loss was evident in both groups. A trendtowards a higher percentage of weight loss, during the 6 months prior to hospital-


Table 1Characteristics of the study population

P-valueWith delirium Without delirium

No. of patients 11 5025/25Female/male 3/880.596.9 N.S.83.296.8Age (mean9S.D.)

N.S.Years of education (mean9S.D.) 5.594.5 6.594.33.092.3No. of chronic medications (Mean9S.D.) 4.591.8 0.057.395.2 B0.00118.296.2Length of hospitalization (days9S.D.)

B0.01No. of chronic diseases (9S.D.) 4.091.2 2.591.3B0.051.091.72.491.9No. of recent hospitalizations (9S.D.)

60.8924.4MMSE on discharge (9S.D.) in percent 38.1927 B0.0522/50 (44%)Patients treated with high risk drugs 11/11 (100%) \0.001

\0.0017/50 (14%)11/11 (100%)Complications during hospitalization1/50 (2%)Mortality 3/11 (27.3%) \0.005

Table 2Ethnic origin of patients

With delirium Without delirium P-value

NS33 (84.6%)6 (15.4%)Ashkenazi JewsNSSephardic Jews 5 (22.7%) 17 (77.3%)

ization, was seen in the delirious group. No difference between groups was observedconcerning lymphocyte count, cholesterol, ferrum and folic acid levels.

Functional decline in both groups is shown in Fig. 1. Delirious patients deterio-rated during hospitalization significantly more than the controls.

In order to be as precise as possible in the diagnosis of delirium, we used twosensitive and reliable methods to detect delirium assessed by two physicians(described in Section 2.2). This approach was chosen in order to reduce thepossibility of overdiagnosis and underdiagnosis, a well-known pitfall in this field(Lyness, 1990; Farrell and Ganzini, 1995). In addition to these two techniques, agood clinical impression by an experienced physician is always useful (O’Keeffe andGosney, 1997).

Table 3Cognition prior to hospitalization (MMSE)

P-valueTotal With delirium Without delirium

5 (17.9%) 23 (82.1%) NSNo dementia 2815 3 (20%)Mild dementia 12 (80%) NS

Severe dementia NS3 (16.7%) 15 (83.3%)1811 (18%)61Total NS50 (82%)


Table 4Source of admission

Without delirium P- valueWith delirium

41Community NS11NS9—Nursing home

Table 5Functional status prior to hospitalization (ADL)

With delirium P- valueWithout deliriumTotal

2/22 (9.1%) 22/22 (90.9%) NSIndependent 2220/26 (76.9%)Mildly dependent 26 6/26 (23.1%) NS10/13 (76.9%) NSCompletely dependent 3/13 (23.1%)1350 (82%)Total 61 11 (18%) NS

Our results highlight several important points which may have substantial clinicalimplications.

3.1. Pre6alence

Delirium among elderly medical inpatients is found in 10–50% (Gillick et al.,1982; Francis et al., 1990). We diagnosed delirium in 18% of our studied popula-tion. Levkoff et al. (1992) reported that 58% of their patients with incident deliriumwere still delirious on discharge from the hospital. Four (50%) of our deliriouspatients who survived, were still delirious on discharge. However, even in thosedelirious patients in which a marked improvement on discharge was noted, theresolution of the clinical signs was not entirely complete. It seems that thesepatients were discharged too early. On the other hand, one must understand thatprolonged stays in the hospital, has, in itself, hazardous consequences.

Table 6Nutritional status

Without delir-Delirium P-valueium

Albumin (g/dl, mean9S.D.) 3.190.5 3.790.6 B0.05Lymphocyte count (cells/mm3, mean9S.D.) 14069849 16029713 NS

NS187947Cholesterol (mg/dl, mean9S.D.) 202966Ferrum (mg/dl, mean9S.D.) 43934 47927 NS

5.792.85.492.0Folic acid (ng/ml, mean9S.D.) NSNS4.995.28.596.3Weight loss in the last 6 months prior to current

hospitalization (percent, mean9S.D.)


Fig. 1. Functional decline during hospitalization (functional status according to Katz activities of dailyliving scale: (A (1), completely independent; G (7), completely dependent).

The fact that a minor event can provoke such a severe psychiatric disorder, mayserve as an indicator that these patients are prone to develop a rapid cognitivedecline (Francis and Kapoor, 1992). The occurrence of delirium should not beconsidered as an episodic, transient event, but as a marker for a high risk group ofpatients who can develop recurrent delirium in the future, even to a minor andapparently nonsignificant trigger.

3.2. Functional status before hospitalization

As was noted by others (Pompei et al., 1994), we found that delirium was morecommon among patients with poor pre-morbid ADL, but without any statisticalsignificance. It is known that patients who are delirious on admission, or becamedelirious during hospital stay, were more dependent in ADL on discharge (O’Keeffeand Lavan, 1997). The significant decline in the Katz score observed in our patients(Fig. 1) compels their families to provide a greater level of assistance in patients’ADL.

3.3. Age

Logically, one should expect a correlation between age and occurrence ofdelirium (Lipowsky, 1989). Surprisingly, we did not find a statistical correlationbetween advanced age and increased prevalence of delirium. This observation isalso shared by others (Levkoff et al., 1992). There is no suitable explanation for thisfinding and hypotheses remain highly speculative.


3.4. Mental status

Although most studies exhibit correlation between cognitive function and occur-rence of delirium (Pompei et al., 1994) we did not find such a correlation in ourstudy. This difference may be due to incomplete and inaccurate informationdelivered by patients’ families. We think that this interesting observation deservesfurther thorough study.

3.5. Nutritional status

It is of relevance to take nutritional status into consideration in the assessment ofa delirious patient. In order to define malnutrition, more than 10% of weight lossshould be noted over a 6-month period prior to current hospitalization. Low levelsof albumin, folic acid, ferrum and low lymphocyte count are also noted. In ourstudy nutritional parameters described were those used to evaluate basic nutritionalstatus. The results suggest that poor nutritional status expressed by level of albuminand by weight loss in the delirious patients (although without statistical significanceconcerning weight loss) plays a certain role in exposing a frail patient to developdelirium. We think that this interesting aspect should be investigated separatelybefore drawing any definite conclusions.

3.6. Ethnic characteristics

In Israel, the population is heterogeneous, and research in any domain andparticularly in the field of cognition and behavior should take into considerationthe variety of ethnic origin as we did in our research. We did not find anysignificant difference between these groups.

3.7. Other risk factors

Other risk factors observed by us are well known: polypharmacy, multiplechronic diseases and the number of recent hospitalizations.

4. Conclusion

The psychiatric presentation is sometimes overwhelming and can mask the cause(infection/metabolic/vascular/polypharmacy/etc.) of delirium leading to misdiagno-sis of this very common geriatric complication. Delirium may be a marker forreduced brain reserve possibly due to an early dementia (Francis and Kapoor,1992). Cerebral metabolic changes during delirium may produce lasting cerebraldamage, resulting in cognitive and functional decline as observed in some of ourpatients. It is highly recommended that these patients, once discharged fromhospital, should be appropriately looked after in order to detect recurrence ofdelirium or chronic deterioration of cognitive function leading to dementia.


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Delirium in an acute geriatric unit: clinical aspects