Accuracy of referring psychiatric diagnosis on a consultation-liaison service
Dilts SL Jr, Mann N and Dilts JG;
Commented by , 28 Oct 2003
Background
27-60% of medical inpatients suffer psychiatric comorbidity, leading to increased morbidity, mortality and cost. Yet, psychiatric disorders continue to be under- and misdiagnosed in the general medical setting.
Purpose
Determine the accuracy of psychiatric diagnoses of primary medical providers requesting psychiatric consultation in a general medical inpatient setting.
Methods
In a U.S. tertiary care center, 346 consecutive consultations to a consultation-liaison (C-L) psychiatry service were retrospectively reviewed over a 3 months. The initial diagnostic impression of primary medical providers was compared with the final diagnosis of the consulting psychiatrists. Statistical differences were established by chi-square and two-sided Fischer’s exact tests.
Results
Referrals to the C-L service represented 3.7% of all patients admitted. Three diagnostic groups – cognitive, substance use and depressive disorders - were dominant in both the initial and final diagnoses, accounting for 56.6% and 80.6% of diagnoses, respectively. 33.8% of initial referrals were for problem-based, nondiagnostic reasons – e.g. “suicide attempt” or “competency.”
Accuracy rates for cognitive, substance use and depressive disorders were 100%, 88.9% and 53.6%, respectively. 26.2% of patients referred as “depressed” were found to have a cognitive disorder. Bipolar, anxiety and psychotic disorders were accurate in 42.8%, 40.0% and 40.0%, respectively. The majority of misdiagnoses in these categories also represented cognitive disorders.
The accuracy of an initial diagnosis of a cognitive or substance use disorder versus a depressive disorder was significantly different (p<0.0001). Similarly, the differences in diagnostic accuracy were significantly greater for cognitive and substance use disorders than anxiety (p<0.001), psychotic (p<0.01) or bipolar (p<0.01) disorders.
Discussion
This study has several limitations. The retrospective nature of the data may misrepresent the diagnostic impressions of the referring physician. For instance, “depressed” may have been intended as a symptom as opposed to a formal diagnosis. Validating the final psychiatric diagnosis with a structured clinical interview would have strengthened the findings, although such interviews are impractical in the general medical setting.
Notwithstanding these limitations, this simple naturalistic study is illustrative of the progress that is required in the management of psychiatric comorbidity in medical inpatients. The inaccuracy of primary medical providers at diagnosing major psychiatric illnesses – mood, anxiety and psychotic disorders – is concerning.
While referring physicians were accurate when they suspected a cognitive disorder, they frequently mistook symptoms of a cognitive disorder for mood, anxiety and psychotic disorders. These disorders are clearly prevalent in general hospital settings, are associated with significant morbidity and mortality, yet are commonly undetected. If physicians on the front line lack the required diagnostic skills, how can we expect improved detection and treatment of these disorders?
The liaison psychiatrist can play an important role in raising the level of psychiatric knowledge and skills among our medical colleagues, particularly targeting these areas of relative deficiency. Undergraduate and postgraduate medical educators also need to “buy in” to the importance of improved training in these areas if we are to anticipate progress.
The absence of initial and final diagnoses of personality disorders is interesting, particularly when this group encompasses 24-28% of primary care patients (1,2). Perhaps it connotes the pejorative label often accompanying such diagnoses, which again speaks to the importance of improved education surrounding this complicated and prevalent group of patients.
References
- Moran P, Jenkins R, Tylee A, et al: The prevalence of personality disorder among UK primary care attenders. Acta Psychiatrica Scandinavia 2000; 102; 52-57
- Casey PR, Tyrer P: Personality disorder and psychiatric illness in general practice. British Journal of Psychiatry 1990; 156; 261-265