Abstract
Objective
Electronic health records (EHRs) are increasingly used to conduct research and evaluate epilepsy quality of care. We examined the accuracy of International Classification of Diseases, 9th and 10th Revision, Clinical Modification (ICD-9-CM, ICD-10-CM)- and antiseizure medicine (ASM)-based algorithms for adult epilepsy.
Methods
Data from a diverse New York multicenter EHR were queried to identify encounters between January 1, 2012 and September 20, 2018 coded with an epilepsy/seizure ICD-CM code or an ASM. Eight hundred adults were randomly selected (350 with epilepsy-related codes, 150 with an ASM, and 300 with drug-resistant epilepsy codes). With chart review defined as the reference standard, sensitivity (Sn), specificity (Sp), negative predictive value (NPV), positive predictive value (PPV), and Youden index (YI) were calculated to evaluate various ICD-9-CM-, ICD-10-CM-, ± ASM-based algorithms’ accuracy in predicting epilepsy.
Results
Ninety-four algorithms were tested. A total of 435 (54.4%) patients had definite epilepsy. Estimates ranged as follows: YI = .18–.68, Sn = .59–.95, Sp = .52–.97, PPV = .67–.92, and NPV = .51–.93. The best algorithms were as follows. Highest YI for ICD-9-CM was single encounter with 345 (except 345.2 or 345.3) or 345.2, 345.3, or 780.3 with an ASM (Sn = .95, Sp = .73, PPV = .81, NPV = .92, YI = .68). Highest Y1 for ICD-10-CM was one encounter with G40 in primary diagnostic position or ≥2 encounters with G40 in any diagnostic position (Sn = .82, Sp = .85, PPV = .87, NPV = .80, YI = .67). Highest sensitivity was any encounter with ICD-9-CM 345 or 780.39 or ICD-10-CM G40, G41, or R56.9 (Sn = .96, Sp = .57, PPV = .73, NPV = .93, YI = .53). Highest specificity was ≥1 hospitalization with ICD-9-CM 345.x (except 345.2 and 345.3) or ICD-10-CM G40.x (Sn = .21, Sp = .97, PPV = .89, NPV = .51, YI = .18).
Significance
We identified ICD-9/10-CM-based case definitions (with and without ASM) that were sensitive and specific for epilepsy. Ultimately, extensive algorithms are provided to help inform case definition selection according to future study aims.
MAY