Current issues of ACP Journal Club are published in Annals of Internal Medicine


Prognosis

Review: Hospitalized elderly patients with delirium have a poor prognosis

ACP J Club. 1993 Nov-Dec;119:87. doi:10.7326/ACPJC-1993-119-3-087


Source Citation

Cole MG, Primeau FJ. Prognosis of delirium in elderly hospital patients. Can Med Assoc J. 1993 Jul 1;149:41-6.


Abstract

Objective

To determine, using meta-analysis, the prognosis of delirium in hospitalized elderly patients.

Data sources

Studies were identified using MEDLINE from January 1980 to March 1992 with key words delirium and aged and using bibliographic review of relevant papers.

Study selection

Articles were selected if they were original prospective studies published in English or French that included ≥ 20 patients aged ≥ 60 years who were followed for ≥ 1 week. The diagnosis of delirium had to be based on an acute deterioration in mental state.

Data extraction

Data were extracted on number of patients and their characteristics, inclusion and exclusion criteria, screening and referral processes, completeness and duration of follow-up, outcome criteria, study quality (including blinded outcome assessment and adjustments for extraneous prognostic factors), mean length of stay, rate of institutional care at 1 and 6 months, mortality rates at 1 and 6 months, and rate of improvement in mental state at 1 month.

Main results

8 studies including 573 patients with delirium were selected. The number of patients ranged from 20 to 144. The length of follow-up ranged from 1 week to 12 months. No study had blinded outcome assessment. Studies varied greatly in how previous dementia, acute illness severity, and need for long-term care were used in the selection of patients and the data analysis. When data were combined, patients with delirium compared with patients without delirium had a longer mean length of hospital stay (21 vs 9 d), a higher rate of institutional care at 1 month (47% vs 18%, {95% Cl for the difference 23 % to 34 %}*) and 6 months (43% vs 8%, {CI for the difference 28% to 42%}*), and a higher mortality rate at 1 month (14% vs 5%, {Cl for the difference 6% to 13%}*) and 6 months (22% vs 11 %, {Cl for the difference 7% to 17%}*). The rate of improvement in mental state at 1 month in patients with delirium was 55%. 2 studies showed an increased mortality rate at 6 months if the patients had dementia, severe illness, or both.

Conclusions

Hospitalized elderly patients with delirium have a poor prognosis with an increased mean hospital length of stay, higher rates of institutional care at 1 and 6 months, and higher mortality rates at 1 and 6 months. The prognosis of delirium may be influenced by the presence of concomitant dementia or severe physical illness.

Source of funding: Not stated.

For article reprint: Dr. M.G. Cole, Psychiatrist-in-chief, St. Mary's Hospital Centre, 3830 Lacombe Avenue, Montreal, Quebec H3T lM5, Canada. FAX 514-734-2636.

*Numbers calculated from data in article.


Commentary

Delirium (acute confusion state) is no longer considered a transient mental disturbance with a favorable prognosis once the precipitating cause is successfully treated. In today's acute care hospital, delirium is highly prevalent, and is most likely to occur in those patients with dementia, advanced age, and severe medical illness, all factors that increase the risk for poor outcomes. Recent studies of the prognosis of delirium (1) have confirmed and extended the meta-analysis of Cole and Primeau. Even after baseline differences in cognitive and physical function, age, and illness severity are taken into account, the occurrence of delirium identifies a subset of older patients at higher risk for mortality, nursing home placement, and functional decline (2). Such poor outcomes occur even in medical units specially designed for the needs of older patients (3).

Delirium continues to be a challenging syndrome both to study and to manage. Patients with delirium can be highly heterogeneous in presentation, with manifestations that vary unpredictably over time (4). Often, the presentation is misdiagnosed as depression (5), which may lead to inappropriate therapies. Furthermore, delirium amplifies existing shortcomings in our systems of care for older persons. It may, for instance, trigger a cascade of adverse events (e.g., chemical and/or physical restraints, deconditioning, falls, aspiration, underhydration) that add to the risk for functional decline. By impairing decision-making capacity, delirium makes informed consent and adherence to therapeutic regimes difficult. Finally, delirium may be slow to resolve, and show persistent effects at time of hospital discharge (6).

The methodological hurdles for a controlled study to prevent poor outcomes in patients with delirium are daunting, and it is not surprising that such studies have yet to appear in the literature. Nonetheless, clinicians need to recognize delirium (fewer than half of patients with delirium are detected by their physicians) and understand its importance. The 8 prospective studies summarized in this analytic review, and the several studies that have followed (1, 7) show that delirium among older patients is not benign, and challenge us to improve our recognition of the disorder and to institute better interdisciplinary management of underlying cognitive and functional problems.

Joseph Francis, MD, MPH
University of TennesseeMemphis, Tennessee, USA


References

1. Elie M, Cole MG, Primeau FJ, Bellavance F. Delirium risk factors in elderly hospitalized patients. J Gen Intern Med. 1998;13:204-12.

2. Inouye SK, Rusing JT, Foreman MD, Palmer RM, Pompei P. Does delirium contribute to poor hospital outcomes? A three-site epidemiologic study. J Gen Intern Med. 1998;13:234-42.

3. O'Keefe S, Lavan J. The prognostic significance of delirium in older hospital patients. J Am Geriatr Soc. 1997;45:174-8.

4. Rudberg MA, Pompei P, Foreman MD, Ross RE, Cassel CK. The natural history of delirium in older hospitalized patients: a syndrome of heterogeneity. Age Ageing. 1997;26:169-74.

5. Farrell KR, Ganzini L. Misdiagnosing delirium as depression in medically ill elderly patients. Arch Intern Med. 1995;155:2459-64.

6. Francis J. Outcomes of delirium: can systems of care make a difference? J Am Geriatr Soc. 1997;45:247-48.

7. Pompei P, Foreman M, Rudberg MA, et al. Delirium in hospitalized older persons: outcomes and predictors. J Am Geriatr Soc. 1994;42:809-15.