Abstracts

RATIONALE: At the end of this presentation, participants should be able to describe factors associated with the use of antiepileptic drugs (AEDs) by nursing home (NH) admissions with bipolar disorder, with/without epilepsy/seizure disorder (Epi/Sz).
In a previous multivariate analysis of epilepsy and AED use among NH elderly, we found a strong association between AED use and bipolar disorder (manic depression). Little research exists about the use of AEDs in the treatment of elderly NH residents with bipolar disorder. Frontline therapy includes antimanic agents (e.g., lithium) and AEDs used as mood stabilizers (e.g., VPA). Because lithium is associated with increased adverse drug reactions among elderly, VPA in particular, as well as other AEDs (GBP, LTG, CBZ, and TPM) are often the treatment of choice. The purpose of this study was to examine the prevalence of and factors associated with AED treatment of NH admissions with bipolar disorder, including Epi/Sz as a comorbidity variable.
METHODS: Subjects were all elderly (N=10,318), [gte]65 years, admitted to 510 NHs located in 31 states during Jan-Mar 1999. Data sources included the Minimum Data Set, a federally mandated, standardized assessment form, and medication orders for all prescription drugs at admission. In a logistic regression analysis, AED use was the dependent variable; covariates included comorbidities, co medications, demographics, clinical characteristics, and functional capabilities.
RESULTS: Of the 10,318 NH admissions, AED prevalence was 7.77%. In the multivariate analysis of factors associated with any AED use, bipolar disorder had an odds ratio (OR) of 10.87; the second highest OR after Epi/SZ disorder. Further analysis of the admissions cohort showed that the prevalence of bipolar disorder was 1.1% (N=113). Of these, 93% (N=105) did not have Epi/SZ as a comorbidity. 30% of the 105 admissions with bipolar disorder had AED use, including VPA (N=21), GBP (N=6), CBZ (N=3), GBP & CBZ (N=1), and GBP &VPA (N=1). Eight others with bipolar disorder also had a comorbidity of Epi/SZ; their AED use included CBZ (N=1), PHT (N=2), VPA (N=3), PHT/GBP (N=1), and PHT/VPA (N=1).
CONCLUSIONS: Little is known about the pharmacoepidemiology of AEDs used as either single or adjunctive therapy for bipolar disorder. Prevalence of bipolar disorder was 1.1% among NH admissions, 1/3 of whom had AED treatment. The majority (66%) of admissions with bipolar disorder without Epi/SZ were being treated with VPA. In the presentation we will discuss additional multivariate relationships between demographic, clinical, and functional variables associated with AED use among NH elderly with bipolar disorder.
*Abbreviations: VPA--valproate, GBP--gabapentin, CBZ--carbamazepine, PHT--phenytoin, LTG--lamotrigine, TPM--topiramate.
[Supported by: NIH-NINDS grant #P50-NS16308.]; (Disclosure: Honoraria - Ilo Leppik, MD: Abbott laboratories, Novartis, Pfizer)