Development and validation of a case definition for epilepsy for use with administrative health data

• Published in: Epilepsy research 2012-12, Vol.102 (3), p.173-179
• Main Authors: Reid, Aylin Y, St.Germaine-Smith, Christine, Liu, Mingfu, Sadiq, Shahnaz, Quan, Hude, Wiebe, Samuel, Faris, Peter, Dean, Stafford, Jetté, Nathalie
• Format: Article
• Language: English
• Subjects: Accuracy; Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Algorithms; Anticonvulsants. Antiepileptics. Antiparkinson agents; Biological and medical sciences; Databases, Factual - statistics & numerical data; Epilepsy - diagnosis; Epilepsy - epidemiology; Epilepsy - physiopathology; Female; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; ICD-10; ICD-9; International Classification of Disease; International Classification of Diseases; Male; Medical Records - statistics & numerical data; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Neurology; Neuropharmacology; Pharmacology. Drug treatments; Reproducibility of Results; Retrospective Studies; Seizure; Sensitivity and Specificity; Young Adult
• ISSN: 0920-1211; 1872-6844
• DOI: 10.1016/j.eplepsyres.2012.05.009

Summary The objective of this study was to develop and validate coding algorithms for epilepsy using ICD-coded inpatient claims, physician claims, and emergency room (ER) visits. 720/2049 charts from 2003 and 1533/3252 charts from 2006 were randomly selected for review from 13 neurologists’ practices as the “gold standard” for diagnosis. Epilepsy status in each chart was determined by 2 trained physicians. The optimal algorithm to identify epilepsy cases was developed by linking the reviewed charts with three administrative databases (ICD 9 and 10 data from 2000 to 2008) including hospital discharges, ER visits and physician claims in a Canadian health region. Accepting chart review data as the gold standard, we calculated sensitivity, specificity, positive, and negative predictive value for each ICD-9 and ICD-10 administrative data algorithm (case definitions). Of 18 algorithms assessed, the most accurate algorithm to identify epilepsy cases was “2 physician claims or 1 hospitalization in 2 years coded” (ICD-9 345 or G40/G41) and the most sensitive algorithm was “1 physician clam or 1 hospitalization or 1 ER visit in 2 years.” Accurate and sensitive case definitions are available for research requiring the identification of epilepsy cases in administrative health data.