Length of hospital stay and health services use of medical inpatients with comorbid noncognitive mental disorders: a review of the literature
Introduction
In the last 30 years, there has been a continuous stream of studies that apparently demonstrate that mental disorders among patients admitted to a general hospital because of their physically ill condition prolong length of stay (LOS). A decade ago, when Saravay and Lavin [1] reviewed 26 studies that assessed the effect of psychiatric comorbidity on the LOS for medical and surgical patients, their conclusions were positive. Most studies included in that review demonstrated an association between psychiatric comorbidity and LOS. The majority of these studies, however, had serious methodological weaknesses. They were retrospective, did not correct for illness severity and the detection of psychopathology was not systematic, but based on referrals or spontaneous identification. Saravay and Lavin concluded that the findings of methodologically sound studies demonstrate that psychiatric cormorbidity contributes to increased costs by extending hospital LOS and by contributing to greater hospital use after discharge from an index admission. In fact, these conclusions were based on four so-called third-generation studies that had a prospective design and were controlling for severity of illness. Three of these four studies were positive; the other one [2] showed negative findings. Of the three positive studies, one concerned the association between delirium and LOS [3]. The other two studies measured a broad spectrum of psychopathology, including cognitive impairment [4], [5]. The correction for illness severity was done by testing the association between illness severity and LOS or between illness severity and psychopathology. Finding these associations to be nonsignificant was considered sufficient reason to conclude that psychopathology and LOS were positively associated.
The empirical evidence as reviewed by Saravay and Lavin is mainly pointing to an association between organic or cognitive mental disorders and hospital resource use. The question whether noncognitive mental disorders are associated with higher resource use in general hospitals is therefore still open. For that reason and because new studies were published in the last decade, we decided to undertake a review of studies on that subject that fulfilled at least some elementary methodological standards, avoiding the internal validity problems of most older studies.
This review aims to test the evidence for the assumption that comorbid mental disorders are associated with higher resource use from general medical services among patients admitted to general hospitals because of their physically ill condition by systematically reviewing the empirical literature on that association.
More specifically, we will focus on noncognitive psychiatric comorbidities and mental health problems, thus, excluding organic disorders like dementia (cognitive impairment), confusional states and delirium. Schizophrenia, other psychotic disorders and personality disorders will also be excluded, as well as substance abuse.
In population studies, the disorders we included are sometimes indicated as “common mental disorders” [6]. This means that, mainly, affective disorders, anxiety disorders and somatization will be included, however, without using strict diagnostic criteria, as used in formal diagnostic classification systems like DSM-IV or ICD-10. The reason for choosing such a broad definition of mental disorders is based on evidence that subthreshold mental disorders may have serious disabling consequences and may therefore affect illness behavior in general and more specifically health service use [7], [8], [9], [10], [11].
To be included in the review, a study should be directed to groups admitted to a general hospital. Assessment of resource use should start with the index admission. The observation period might be restricted to the admission only or might be extended to a longer period.
Section snippets
Method
This review is part of a more comprehensive review of the literature concerning not only inpatient studies, but also outpatient and population studies. For that comprehensive review, a literature search was conducted using Medline and PsychLit databases from 1984, with several search terms related to mental health problems (excluding organic disorders, schizophrenia, psychotic disorders, personality disorders) and utilization of general health care services. Search terms used for mental health
Results
The initial searches (in 2001) of Medline and PsychLit, tables of contents of selected journals and reference lists produced 484 references. After reading the abstracts to check whether the content of the study matched the aim of the review, 289 studies were eliminated. It proved to be impossible to make a reliable judgment of the research design based on information contained in the abstracts. Therefore, the decision to include a study meeting the research quality criteria was made after
Discussion
We reviewed 20 inpatient studies that all fulfilled some elementary methodological criteria of internal validity. Three studies combined a short observation period (during index admission) with a longer observation period during follow-up and were, therefore, considered to be composed of two separate studies published as one study.
The 15 studies that were restricted to service use during index admission showed mixed results. The eight studies that used a longer observation period showed
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