Delays and disparities in diagnosis for adults with epilepsy: Findings from U.S. Medicaid data

Abstract

Objective: To identify disparities in care pathways and time from first seizure to epilepsy diagnosis, we examined 2010-2014 Medicaid claims (including pharmacy) data from 16 States for individuals with incident epilepsy.

Methods: We identified adults (18-64) with an incident epilepsy diagnosis from 1/2012 through 6/2014. These individuals were enrolled in Medicaid for the entire study period and had no history of anti-epileptic drug (AED) use before their first seizure claim. We identified care pathways and calculated the duration from initial seizure to epilepsy diagnosis. We tested associations between these pathways and race/ethnicity, as well as time differences between care pathways using a Chi-squared and Kruskal-Wallis tests.

Results: The 14,337 adults followed five different care pathways. Their overall median duration from first seizure code to epilepsy diagnosis code was 19.0 months (interquartile range: 4.6, 30.4), and 56.0% filled an AED prescription. Some minorities were more likely to follow pathways with increased durations and delay to diagnosis, and the duration to diagnosis varied significantly across the care pathways.

Significance: The many different care pathways seen in people with epilepsy show substantial and significant time delays between first seizure diagnosis and epilepsy diagnosis, including significant racial/ethnic disparities that warrant attention.

Keywords: Anti-epileptic drug; Diagnosis; Diagnosis delay; Disparities; Medicaid; Time to diagnosis.

Figure 1.

Timeline showing the timeframe in which first epilepsy diagnosis was identified, as well as the minimum lookback and follow-up periods. The minimum lookback time for seizure demonstrates that at the minimum we would have 2-years of epilepsy-free claims leading up to the epilepsy diagnosis, for a person whose first epilepsy claim were to be on January 1, 2012. Most individuals had more than just the 2-year minimum. Seizure claims were identified at any time point up to their first epilepsy diagnosis date (not restricted to 2-years).

Figure 2.

The 5 care pathways that emerged in the analysis. The dashed lines represent that only a portion of individuals will go from epilepsy diagnosis to treatment (see Table 1). ^†There were 1,979 individuals who received an AED after their first seizure and continued to have seizure claims (1,401 individuals in Path 3 and 578 individuals in Path 4).

Figure 3.

Time (median, interquartile range, and range) from seizure to epilepsy diagnosis (in months) by pathway, as shown in Figure 1, demonstrating the substantial delays between seizure and epilepsy diagnosis as well as significant difference between pathways. There are significant differences both globally (p < 0.001), as well as between all pairwise comparisons except between Path 2 and Path 4, Path 2 and Path 5, and Path 4 and Path 5 (p = 0.85, p = 1.00, p = 0.45, respectively). Note: outliers have been visually removed in order to comply with data protection requirements under the Data Users Agreement.

Figure 4.

Proportion of pathway within race/ethnicity groups, demonstrating the disproportionate number of American Indian, Alaskan Native, Asian, Pacific Islander, Native Hawaiians and Other Pacific Islander (AIAN/API/NHOPI) who fall into Path 3, the path with the longest time between seizure and epilepsy, compared to the other races.

Figure 5.

Time (median, interquartile range, and range) from seizure to epilepsy (in months), by path and race/ethnicity. The upper left panel represents the overall values, and the others are stratified first by path and then by race/ethnicity. This figure demonstrates the highly variable time from seizure to epilepsy diagnosis across paths and race/ethnicity. Note: outliers have been visually removed in order to comply with data protection requirements under the Data Users Agreement.