Risk of admission within 4 weeks of discharge of elderly patients from the emergency department—the DEED study

Age and Ageing, Nov, 1998 by Gideon A. Caplan, Ann Brown, William D. Croker, Janis Doolan

Abstract

Objective: to identify risk factors for admission for patients aged 75 years and older after discharge from the emergency department (DEED: discharge of elderly from emergency department).

Design: prospective evaluation of discharged elderly patients from the emergency department who were followed up after 4 weeks.

Setting: emergency department of a teaching hospital for 1 year.

Subjects: patients aged 75 and over discharged to their home or hostel. Main outcome measures: demographic data, indices of function and cognitive status and admission to hospital within 4 weeks.

Results: 468 patients aged 75 and over (mean age 81.7 years; range 75-98) were enrolled; 80 patients (17.1%) were admitted to hospital during the subsequent 4 weeks. Risk factors for admission included dependence in the following activities of daily living (relative risk; 95% confidence interval): bathing (2.41; 1.32-4.41); dressing (2.38; 1.22-4.63); stairs (1.60; 1.09-2.33); finance (1.66; 1.23-2.25); shopping (1.39; 1.12-1.73) and transport (1.61; 1.25-2.06), as well as use of a community nurse (1.88; 1.12-3.17). Logistic regression analysis found two variables to be significant in predicting admission or not: dependence in transport and use of a community nurse.

Conclusions: older patients are at increased risk of readmission within 4 weeks of being sent home from the emergency department. It is possible to identify high-risk patients by a questionnaire. This allows targeting of these patients for more intensive follow-up in an attempt to ameliorate further deteriorations in their health.

Keywords: activities of daily living, emergency department, frailty, old age

Introduction

Patients over 75 more commonly present to and are also more often admitted to hospital from the emergency department (ED) than younger patients [1, 2]. Many of those who are not admitted to hospital, and are therefore discharged from the ED, will suffer a deterioration of their health or function, and approximately 20% will be admitted to hospital within the next month [3-5]. Many of these admissions may be preventable.

It is not clear from the published data why older patients have an increased risk of admission. This increased risk is not unique to the ED, but also occurs after discharge from surgical, medical and geriatric wards [6]. The effects of disease on frail, older people frequently lead to a cascade of illness and functional decline resulting in excess physiological morbidity and mortality [7]. This suggests that the increased risk of admission is due to frailty [8]. Frailty has never been precisely defined, but is used to describe patients, mainly over age 65, whom the burden of chronic disease leaves more vulnerable to environmental challenges. We hypothesized that standardized assessments of function, mental and social status would identify frail patients at risk of admission within the next month and designed the DEED (discharge of elderly from emergency department) study to test this hypothesis.

Methods

This study was conducted in the ED of a 361-bed teaching hospital attached to a university. The ED is an area trauma centre staffed by staff specialists and registrars in emergency medicine as well as by residents and interns on rotation. The population in the catchment area of the hospital includes 7.1% aged 75 years and over [9]. At our ED patients over 75 comprised 14.4% of all presentations, approximately double their representation in the population. This over-representation by a factor of two is in accord with other data [10].

We studied all patients aged 75 years and over who were discharged from the ED from 7 April 1994 to 6 April 1995. During the year of our study 3974 patients aged 75 and over presented to the ED, 2343 of these were admitted and 57 were dead on arrival. Patients were excluded if they met the following criteria: living out of area (121), living in a nursing home (246), eligible for the care of already existing intensive outreach services in orthogeriatrics, palliative care or psychiatry (56) or already in the study (211). These intensive outreach services already offer multidisciplinary interventions--medical, nursing and allied health--treating at home patients who may otherwise require admission. Only after the decision was made to discharge the patient was informed consent obtained. An additional group of patients declined consent (209) or were missed (263).

All patients who consented to enter the study answered a questionnaire covering living arrangements, background of the presentation to the ED, the Barthel index of activities of daily living (ADL) [11], a modified instrumental ADL index (IADL) [12] and the Short Portable Mental Status Questionnaire (MSQ) [13].

After 28 days patients were contacted by phone and visited at home, where detailed inquiry into the use of health services and the reason for that use during the study period was carried out. The study was approved by the hospital's ethics committee.

Risk of admission was calculated by dichotomizing individual's performance in each item of the ADL and IADL indices into fully independent or dependent to any degree. Statistical analyses were performed using Epi Info (USD Inc., Stone Mountain, GE, USA) for relative risks (RRs) and SPSS for Windows (SPSS Inc., Chicago, IL, USA) for logistic regression. For the logistic regression analysis, variables were entered into the model in a variety of combinations and analysed by automated model building to find the combination of variables with the best interpretability and parsimony, as recommended by the software.