title: Factors associated with seizure recurrence in epilepsy patients treated with antiepileptic monotherapy: A retrospective observational cohort study using US administrative insurance claims.
abstract: BACKGROUND
  Few studies examine predictors of seizures in medically treated patients with epilepsy receiving antiepileptic monotherapy using a large patient population.
  
  
  OBJECTIVE
  Our objective was to identify clinical, medication, and demographic factors associated with seizure recurrence in medically treated patients with epilepsy receiving one of four antiepileptic monotherapy regimens: lamotrigine, levetiracetam, oxcarbazepine, or topiramate.
  
  
  METHODS
  A retrospective cohort study was conducted using Innovus Invision™ Data Mart paid medical and prescription US commercial insurance claims data from January 2007 to September 2010.
  
  
  METHODS
  Patients aged 18-64 years with a primary or secondary diagnosis of epilepsy and one or more prescription claim for an antiepileptic drug (AED) pre-index were included. The primary outcome was incidence of a seizure or seizure-related event, defined as an emergency room visit, ambulance service use, or inpatient hospitalization medical claim with a primary or secondary diagnosis of epilepsy during the 1-year follow-up. The factors included AED adherence, somatic comorbidity (measured via Charlson Comorbidity Index), mental health comorbidity, pre-index seizure, type of epilepsy diagnosis, presence of AED-interacting medications and any bioequivalent AED switch. The covariates included age, gender, and geographic region of residence.
  
  
  RESULTS
  A total of 5.3 % (166/3,140) of patients on AED monotherapy had experienced a seizure or a seizure-related event requiring urgent care at 1-year follow-up. The multivariate analysis of the combined cohort showed that pre-index seizures/seizure-related events (odds ratio [OR] 4.23; 95 % confidence interval [CI] 2.77-6.46), any mental health comorbidity (OR 3.50; 95 % CI 2.14-5.70), and Charlson Comorbidity Index ≥1 (OR 2.91; 95 % CI 1.98-4.28) were significantly associated with post-index seizures/seizure-related events. Patients residing in Northeastern USA had a higher likelihood of a post-index seizure (OR 1.90; 95 % CI 1.17-3.08) than patients residing in the Southern region of the USA. Bioequivalent AED switch, type of epilepsy diagnosis, AED adherence, and presence of AED-interacting medications were not associated with seizure recurrence in the combined cohort analysis (p > 0.05).
  
  
  CONCLUSIONS
  Epilepsy patients with comorbid conditions (both mental and somatic diseases) and prior seizures were more likely to experience seizures at 1-year follow-up. Non-adherent patients and patients with bioequivalent AED switches appeared to show no increased likelihood of seizure at follow-up. Clinicians may consider these findings before starting or transitioning to an AED monotherapy.
authors.affiliation: Department of Pharmaceutical and Administrative Sciences, College of Pharmacy, Western New England University, 1215 Wilbraham Road, Springfield, MA, 01119, USA, natalia.shcherbakova@wne.edu.
authors.forename: Natalia
authors.initials: N
authors.lastname: Shcherbakova
authors.forename: Karen
authors.initials: K
authors.lastname: Rascati
authors.forename: Carolyn
authors.initials: C
authors.lastname: Brown
authors.forename: Kenneth
authors.initials: K
authors.lastname: Lawson
authors.forename: Suzanne
authors.initials: S
authors.lastname: Novak
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Richards
authors.forename: Linda
authors.initials: L
authors.lastname: Yoder
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000008:administration & dosage* / Q000627:therapeutic use*; D015897:Comorbidity; D003627:Data Interpretation, Statistical; D016208:Databases, Factual; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D017723:Drug Utilization Review; D004827:Epilepsy / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control; D006801:Humans; D007348:Insurance, Health; D008875:Middle Aged; D015995:Prevalence; D012008:Recurrence; D012189:Retrospective Studies; D014481:United States; D055815:Young Adult
chemical_list: D000927:Anticonvulsants
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