Misdiagnosed patients with bipolar disorder: comorbidities, treatment patterns, and direct treatment costs.
OBJECTIVE
The purpose of this study was to examine comorbidities, treatment patterns, and direct treatment costs of patients with bipolar disorder who are misdiagnosed with unipolar depression.


METHODS
This study is a retrospective analysis of data from the MarketScan Commercial Claims and Encounters (CCE) database. Logistic regressions and analyses of variance were used to compare the misdiagnosis cohort to 3 age- and gender-matched comparison cohorts (recognized bipolar, depression, and no psychiatric disorders based on ICD-9-CM criteria) during the year 2000.


RESULTS
Each cohort had 769 individuals (68.0% female; mean age of roughly 42 years). The misdiagnosis cohort had higher rates of several psychiatric comorbidities than the depression cohort (e.g., personality disorders, alcohol abuse, psychotic disorder) and the bipolar cohort (e.g., generalized anxiety disorder, panic) but a lower rate of psychotic disorders than the bipolar cohort (p < .05). Compared with the bipolar cohort, the misdiagnosis cohort was more likely to receive antidepressants, but less likely to receive anticonvulsants, antipsychotics, or lithium (all p < .001). Antidepressant rates were similar among the misdiagnosis and depression cohorts. Group differences were found in mean annual costs for anticonvulsants, antipsychotics, lithium, antidepressants, and total treatment costs: bipolar (USD $442, $310, $67, $497, $8600); misdiagnosis (USD $221, $185, $20, $704, $8761); depression (USD $70, $74, $5, $657, $7288).


CONCLUSIONS
Misdiagnosed bipolar patients received inappropriate and costly treatment regimens involving overuse of antidepressants and underuse of potentially effective medications. Patterns of psychiatric comorbidity suggest one possible strategy for improving recognition of bipolar disorder among patients presenting with depressive symptoms. Patients who present with the observed pattern of comorbidities may benefit from additional screening for bipolar disorder. It is recommended that steps be taken to minimize misdiagnosis in clinical settings.
Matza
Louis S
LS
The MEDTAP Institute at UBC, 7101 Wisconsin Avenue, Suite 600, Bethesda, MD 20814, USA. louis.matza@unitedbiosource.com
Rajagopalan
Krithika S
KS
Thompson
Christine L
CL
de Lissovoy
Gregory
G
D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology; D015331:Cohort Studies; D019992:Databases as Topic / Q000706:statistics & numerical data; D003695:Delivery of Health Care / Q000191:economics; D003866:Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D004180:Direct Service Costs / Q000706:statistics & numerical data*; D016527:Drug Costs / Q000706:statistics & numerical data; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases / Q000706:statistics & numerical data; D008094:Lithium / Q000627:therapeutic use; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology; D012189:Retrospective Studies
D000928:Antidepressive Agents; D014150:Antipsychotic Agents; D008094:Lithium