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Prognosis of delirium
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  1. Toshi A Furukawa
  1. Kyoto University Graduate School of Medicine/School of Public Health, Kyoto, Japan; furukawa{at}kuhp.kyoto-u.ac.jp

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Clinical case

Patient: a woman aged 77 years

Present illness

The patient had type II diabetes since her 50s which had been fairly well controlled and also suffered from an old myocardial infarction, but had been able to live alone in her apartment, managing the household on her own. She caught a common cold several days ago, which worsened the next few days, and the patient was febrile, unable to eat or drink. The daughter living in the neighbourhood took her to the hospital, where she was diagnosed with severe pneumonia and dehydration and was hospitalised. In the general medicine ward, however, she developed delirium the night she was admitted.

Present status

At night, she was agitated and claimed that she had to go to work and that her husband (deceased) was in the room. She was often somnolent during the day, although she did have some relatively clear moments. She was able to communicate at those moments, but her attention was short and her speech was often incoherent.

Course of illness

Dehydration and pneumonia responded well to medical treatments but chronic heart failure persisted. As a consultant psychiatrist to the medical ward, you confirmed that the best supportive environment was provided, medications that may cause delirium were avoided and low-dose risperidone was prescribed to control delirium. However, delirium persisted, and after the medical managements for her diabetes and chronic heart failure were stabilised, the patient was discharged to the nursing home.

You wonder what percentage of patients who develop delirium in the hospital would be still delirious on discharge, and what would become of their delirium after discharge.

Formulate your clinical question

  • Patients: Patients who develop delirium in the hospital

  • Intervention: ---

  • Comparison: ---

  • Outcomes: Likelihood of delirium on hospital discharge and beyond

Literature search

The highest level evidence for prognosis can be obtained from prospective cohort studies and their systematic review. Findings from long-term randomised controlled trials can sometimes be informative, but the populations studied in them tend be limited in severity and comorbidity. On the other hand, prospective cohort studies can provide findings with possibly greater generalisability.

In order to identify studies on prognosis, Clinical Queries of PubMed remain the easiest and most efficient portal (http://www.ncbi.nlm.nih.gov/pubmed/clinical). First, you visit MeSH database to identify MeSH keywords corresponding with delirium. It was indeed ‘delirium’ and you searched ‘delirium’ (MeSH) in the Clinical Queries for the ‘category: prognosis’ and ‘scope: narrow’, using the drop-down menu. There were 681 articles and 345 reviews. Browsing first through the list of reviews, clicking on the potentially relevant reviews and then also checking the ‘Similar articles’ (this often proves to be an efficient way to identify relevant studies), you found a systematic review on persistent delirium: Cole et al.1 From the list of their included studies, you pick up the one with the largest number of participants and which is mostly likely to answer your clinical question: McCusker et al.2

What will you do with your patient?

The overall course of inhospital delirium was surprisingly chronic. Moreover, if delirious at discharge, one in three patients were dead within 12 months postdischarge, regardless of the presence or absence of dementia. Although there is nothing that I can do now that the patient herself has been discharged to a nursing home, you realise how important it is to manage, if possible, the delirium before discharge.

Critical appraisal of the literature on diagnostic test

ARE THE RESULTS AT RISK OF BIAS?

Was the sample of patients representative?

Probably yes. The sample was a consecutive sample of old patients admitted to general medical services of a 400-bed university-affiliated, primary acute care hospital

Were the patients sufficiently homogeneous with respect to prognostic risk?

No. Patients were therefore divided into those with dementia and those without dementia

Was the follow-up adequate and sufficiently complete?

Yes. All the patients were followed up to 12 months postdischarge or until death

Were outcome criteria objective and unbiased?

Probably yes. Delirium symptoms were assessed with the Delirium Index by a research assistant, based solely on patient observation, and the diagnosis was given in accordance with DSM-III-R criteria

WHAT ARE THE RESULTS?

How likely are the outcomes over time?

The likelihood of being in delirium was 32% (61/193, 95% CI 25% to 39%) at discharge, 32% (45/143, 24% to 40%) at 6 months postdischarge and 41% (49/119, 33% to 50%) at 12 months postdischarge

Figure. Proportion of patients in delirium at 0, 6 and 12 months postdischarge for people with or without dementia

How precise are the estimates of likelihood?

The CIs for the likelihood of being in delirium were as shown in the above figure, and were very wide, especially for those without dementia

HOW CAN I APPLY THE RESULTS TO PATIENT CARE?

Were the study patients and their management similar to those in my practices?

Probably yes

Can I use the results in the management of patients in my practice?

Yes. Not for this patient but for the next patients

References

Footnotes

  • Competing interests TAF has received lecture fees from Eli Lilly, Janssen, Meiji, MSD, Otsuka, Pfizer and Tanabe-Mitsubishi, and consultancy fees from Sekisui Chemicals. He has received royalties from Igaku-Shoin and Nihon Bunka Kagaku-sha publishers. He has received research support from Mochida and Tanabe-Mitsubishi.

  • Provenance and peer review Commissioned; externally peer reviewed.