Abstracts

Rationale: Persons with epilepsy (PWE) often have multiple concurrent diseases. Nonetheless, the pattern of these co-occurring conditions in PWE remain largely unexplored. This study was designed to examine the pattern of comorbid conditions and the extent of its variation in PWE.Methods: We performed a retrospective dynamic cohort study using Ohio Medicaid data from 1997-2008 to identify a total of 1,931 incident epilepsy cases. Subjects entered our cohort if they were between 18 and 64 years of age at the time of epilepsy diagnosis. We measured the prevalence of 23 common conditions that were selected based on their commonality in the epilepsy population and their impact on the patient s outcome. The conditions that occurred prior to epilepsy diagnosis were classified as pre-existing conditions. To assess combinations of co-occurring conditions, the most common 3 conditions that coexisted in the same subject (triplets) were determined. Three-way disease clusters were used as the main unit of analysis. An individual subject could have >1 triplet. An observed-to-expected approach was used to compare the observed prevalence of 3-way disease clusters with the prevalence that would have been expected if all diseases were independent.Results: The mean number of pre-existing conditions was 5.5 4. Hypertension, depression, psychosis, chronic pulmonary diseases, and diabetes were the most common pre-existing conditions. The most common 3-way combination of pre-existing conditions was hypertension, psychosis, and depression, which together occurred in 17.5% of men, and 17.5% of women. After epilepsy diagnosis, the mean number of comorbid conditions increased to 6.4 4. The 5 most common pre-existing conditions continued to be the most common concurrent conditions after epilepsy diagnosis. Moreover, a combination of hypertension, depression, and psychosis remained the most common 3-way combination of concurrent conditions in both men (24.8%) and women (33.8%) with epilepsy. Conclusions: Comorbid conditions in PWE mostly occur prior to epilepsy diagnosis. Specific combinations of concurrent diseases are highly prevalent in PWE. Accounting for these combinations of comorbid conditions is essential for developing integrated care and for minimizing drug-drug and drug-disease interactions.