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Exploring differential prescribing between anti‐epileptic drugs in epilepsy patients with a history of mood disorders
Author(s) -
Ishihara Lianna,
Webb David J.,
Irizarry Michael,
Weil John
Publication year - 2010
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.1905
Subject(s) - medicine , epilepsy , psychiatry , mood disorders , carbamazepine , oxcarbazepine , mood , medical prescription , bipolar disorder , gabapentin , pediatrics , lamotrigine , pharmacology , alternative medicine , anxiety , pathology
Purpose To explore differential prescribing of anti‐epileptic drugs (AEDs) to patients with epilepsy by history of mood disorder. Methods Epilepsy was defined as at least one diagnosis code and one AED prescription, and all patients must have been on the database 182 days before and after their first AED prescription. The Integrated HealthCare Information Services (IHCIS) insurance claims database included 44 557 patients with epilepsy between January 1997 and March 2007. The General Practice Research Database (GPRD) included 16 904 patients with epilepsy up to March 2007. Patients were categorized by their first use of specified AEDs. Mood disorders were defined as diagnosis codes for depression and bipolar disorder, or anti‐depressant use. The unadjusted odds ratios and 95% confidence intervals for a history of mood disorder diagnosis ever or within the three months prior to AED use were calculated with carbamazepine and oxcarbazepine (CBZ) as the referent. Results In the US IHCIS, a history of mood disorders was significantly more common in new users of most AEDs compared to CBZ new users, indicating differential prescribing. Clonazepam and gabapentin were the most commonly prescribed AEDs in patients with epilepsy and a history of mood disorders. In the UK GPRD, there was less evidence of differential prescribing of AEDs, although gabapentin was prescribed most often to epilepsy patients with a history of mood disorders. Conclusions Any observational studies of AEDs and suicidality would have to consider potential channeling bias by history of mood disorders, which is a major risk factor for suicide. Copyright © 2010 John Wiley & Sons, Ltd.