Applying comparative effectiveness research methods in bipolar disorders.
BACKGROUND
Randomized clinical trials [RCT] are the Gold Standard of medical evidence. However, observational comparative effectiveness research [CER] based on real-world data is receiving national attention. This paper demonstrates how observational CER can fill important gaps in clinical knowledge left behind by RCT approaches. An example of CER in bipolar disorders is presented.


METHODS
Paid claims data from a large commercial insurer were used to identify episodes of drug therapy. Episodes were defined each time a patient initiated or restarted therapy using an antipsychotic, antidepressant or mood stabilizing medication. Episode definitions were based on calculations of continuous days of drug therapy using a 15 day gap definition. 105,440 episodes of drug therapy were included in the analysis.


RESULTS
Most episodes were initiated using a mood stabilizing drug (40%) or an antidepressant (40%). Over 59% of all episodes were for augmentation therapy, followed by switching episodes (25%) and restart episodes (16%). Patient outcomes measured by either duration of uninterrupted therapy or one-year post-treatment cost varied significantly with patient treatment history, especially episode type. The comparative effectiveness of alternative therapies was sensitive to the extent to which treatment history is taken into account.


CONCLUSIONS
Observational research can evaluate patient outcomes across a wide range of clinical presentations with regard to the patient's treatment history. Treatment history is a major determinant of patient compliance and future treatment costs. Failure to account for treatment history can introduce bias into comparative effectiveness results. Observational CER research can also uncover important questions that require future research.
Department of Clinical Pharmacy and Pharmaceutical Economics and Policy, School of Pharmacy, University of Southern California, 1540 E. Alcazar St., Rm. CHP 140, Los Angeles, CA 90080-9004, United States. jmccombs@usc.edu
Jeffrey S
JS
McCombs
Vaidyanathan
V
Ganapathy
Sara
S
Zolfaghari
D000293:Adolescent; D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000191:economics / Q000627:therapeutic use; D058633:Antipyretics / Q000191:economics / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy* / Q000191:economics; D002648:Child; D057186:Comparative Effectiveness Research / Q000379:methods; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011619:Psychotropic Drugs / Q000191:economics / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D016896:Treatment Outcome; D055815:Young Adult
D000928:Antidepressive Agents; D058633:Antipyretics; D011619:Psychotropic Drugs