Rationale:
There are many uses of a list of diagnoses with seizure risk. Epidemiologically, prevalence and impact of seizures could be evaluated. For healthcare quality, utilization of resources such as emergency departments and EEGs could be examined in people at risk of seizures. For inpatients, evaluation of seizure testing and treatments could be assessed relative to outcomes and cost of care. While payers already use their own lists to determine coverage, to our knowledge there is no scientifically vetted list of diagnostic codes associated with risk of seizure. Here, we describe the creation of such a list, with the intention of making it widely available for further investigation.
Methods:
Beginning with all diagnosis codes in the International Classification of Disease (ICD-10) (CMMS, 2019), those with seizure risk were identified along three axes: (a) diseases of the brain or central nervous system (CNS), (b) seizures and epilepsy, (c) diagnoses known to increase risk of seizures. ICD codes corresponding to brain pathology were identified by including all ICD codes with descriptions that contained relevant terms (e.g., “cereb”). Specific diagnoses with risk for seizure were collected from online resources and publications and corresponding ICD codes were identified. All included codes were reviewed by an epileptologist (GM). Duplicate codes as well as codes with no risk of seizure were removed. The final ICD code list was categorized by diagnostic category, anatomical location, and seizure risk. Diagnostic categories included: Metabolic, Vascular, Inflammatory, Trauma, Infectious, Genetic, Epilepsy/Seizure, Tumor, Congenital, Dementia, and Other. Anatomical categories included Brain/Meninges, Mixed CNS (brain and spinal cord), Neuro Not CNS (peripheral), Mixed Neuro (CNS and PNS), Not Neuro (e.g. sepsis) and Mixed Not Neuro and Neuro (e.g. acquired syphilis). Seizure risk category was designated by independent ranking of each code by three physicians (two epileptologists [GM, SA] and one neurohospitalist [PS]). Seizure risk assigned by each physician was given a point value and summed to create a final seizure risk categorization of none, low, medium, and high (see figure). Codes with a final seizure risk of “none” after recategorization were removed from the final list.
Results:
Beginning with 71,932 total ICD codes, 4,311 were selected for initial inclusion. After removal of 192 duplicates and 778 with no risk of seizure, the list included 3,341 codes with associated seizure risk. The list may be accessed at
https://hartfordhealthcare.org/seizureriskcodes, and can be filtered by diagnostic category, anatomical location, and seizure risk. Conclusions:
This study resulted in a list of ICD-10 diagnosis codes associated with risk of seizures. Evaluation of actual seizure risk should be performed in large populations (e.g., epidemiological data) as well as focused scenarios (e.g. inpatients with EEG confirmation). This list is immediately available and offers improved opportunity for identifying people at risk of seizures for research within epidemiology, quality, and healthcare access domains.
Funding: Not funded