Identification of Drug Resistance in a Validated Cohort of Incident Epilepsy Patients in the Danish National Patient Register

July 28, 2023

Abstract found on PubMed

Objective: The main purposes of this study were to validate the epilepsy diagnosis in incident epilepsy cases in the Danish National Patient Registry (DNPR), containing information on nearly 9,000,000 individuals; and identify persons in the validated cohort who fulfilled the International League Against Epilepsy (ILAE) criteria for drug resistant epilepsy (DRE).

Methods: We reviewed a random sample of medical records from all individuals registered with a first diagnosis of epilepsy (ICD-10: G40) or seizures (ICD-10: G41, R56, or F445) in Central Denmark Region from 2010-2019. In persons with a validated incident epilepsy diagnosis, we determined the proportion with DRE at the latest contact. We performed logistic regression analyses to identify clinical factors that correlated with risk of DRE.

Results: Of 20,723 persons with a first diagnosis of epilepsy (n=11,812) or seizures (n=8,911), we reviewed the medical records of n=1,067 with incident epilepsy and n=610 with incident seizures. Among those with a register diagnosis of epilepsy, the diagnosis was confirmed in 838 cases (45% females, mean age at onset = 42.4 years), providing a positive predictive value (PPV) of 79% (95% CI: 76-81%). The PPV of focal epilepsy was 86% (95% CI: 82-89%), and the PPV of generalized epilepsy was 71% (95% CI: 61-80%). Of 740 patients with confirmed incident epilepsy and ? 1 year of follow-up, 103 (14%) fulfilled the definition of DRE, 476 (64%) were drug responsive, and 161 (22%) had undefined responsiveness. In multivariable logistic regression analysis, early age at epilepsy onset, cognitive impairment, and a history of status epilepticus were associated with DRE.

Significance: In the Danish National Patient Registry, we found a positive predictive value of the epilepsy diagnosis of 79%. Among persons with confirmed epilepsy, 14% fulfilled ILAE criteria of drug resistant epilepsy. Early age at epilepsy onset, cognitive impairment, and a history of status epilepticus were independently associated with drug resistance.