Does sponsored genetic testing for pediatric epilepsy expand access?
Clinical Genetics and Therapeutics
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Primary Categories:
- Health Care Inequities and health disparities
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Secondary Categories:
- Health Care Inequities and health disparities
Introduction:
Several genetic testing companies and biopharmaceutical companies have partnered to offer industry-sponsored genetic testing programs (STPs). These programs remove cost barriers to genetic testing to enable development of precision therapies and more efficient access to, and awareness of, targeted care. The purpose of this study was to retrospectively examine the population differences, delay in diagnosis, and results of patients who had genetic testing for epilepsy inside an STP (I-STP) and outside an STP (O-STP).
Methods:
Unrelated probands were tested I-STP and O-STP between December 2016 and June 2024 on a multigene epilepsy panel (89-302 genes). Inclusion criteria were patients <96 months at age of testing and residing in the United States. Demographic and clinical information were provided by the ordering clinician on the test requisition form. We used publicly-available census tract-based dataset, the Child Opportunity Index (COI) 3.0 (https://www.diversitydatakids.org/child-opportunity-index) to assign individuals to nationally normed socioeconomic status (SES) scores from their ZIP codes. The COI 3.0 is a composite index of 44 indicators of children’s education, health, and environmental neighborhood conditions developed in 2024 by the Kirwan Institute for the Study of Race and Ethnicity at Ohio State University. To evaluate differences between I-STP and O-STP cohorts, P-values were calculated using both parametric and non-parametric tests, where appropriate; analysis of variance and logistic regression were employed to test multiple factors.
Results:
Significantly more individuals were tested I-STP (N=45,836) than O-STP (N=11,639). Black and White individuals were more likely to get tested I-STP, while Asian, Hispanic and individuals noted to have multiple ethnicities were more likely to get tested O-STP (p<0.005). I-STP was more likely to have high and very high SES, while individuals tested O-STP were more likely to have very low and low SES. The age of seizure onset was lower in O-STP compared to I-STP cohort (I-STP 28.24 months vs 23.29 months, p<0.0001). Individuals from I-STP had a shorter time to testing than O-STP (I-STP 16.02 months vs. O-STP 18.78 months, p<0.0001). Across both cohorts, compared to White individuals, Black and Hispanic individuals were found to have a longer time to testing (White 15.67 months; Black 16.87 months; Hispanic 17.40 months, p<0.005). The overall positive diagnostic rate was higher for O-STP than I-STP (15.94% vs 13.14%, p<0.0001). Lastly, logistic regression analysis revealed that ethnicity, sex, age of onset and time to testing all significantly affected molecular diagnosis rate.
Conclusion:
We found unexpected differences among race/ethnicity groups and SES of patients who underwent genetic testing I-STP versus O-STP, highlighting inequity among marginalized groups compared to White individuals. Our study was limited to the experience of one commercial laboratory. Though we analyzed variables known to contribute to pediatric epilepsy, additional confounding factors may be unknown. This demands further research on the relative importance of factors that affect access to genetic testing, such as provider awareness, perceived clinical utility of genetic testing, and systemic health inequities through a biopsychosocial lens. Ultimately, significantly more patients were tested I-STP and, notably, they had a shorter time from clinical diagnosis to genetic testing and a similar molecular diagnosis rate as individuals whose testing was performed O-STP.
Several genetic testing companies and biopharmaceutical companies have partnered to offer industry-sponsored genetic testing programs (STPs). These programs remove cost barriers to genetic testing to enable development of precision therapies and more efficient access to, and awareness of, targeted care. The purpose of this study was to retrospectively examine the population differences, delay in diagnosis, and results of patients who had genetic testing for epilepsy inside an STP (I-STP) and outside an STP (O-STP).
Methods:
Unrelated probands were tested I-STP and O-STP between December 2016 and June 2024 on a multigene epilepsy panel (89-302 genes). Inclusion criteria were patients <96 months at age of testing and residing in the United States. Demographic and clinical information were provided by the ordering clinician on the test requisition form. We used publicly-available census tract-based dataset, the Child Opportunity Index (COI) 3.0 (https://www.diversitydatakids.org/child-opportunity-index) to assign individuals to nationally normed socioeconomic status (SES) scores from their ZIP codes. The COI 3.0 is a composite index of 44 indicators of children’s education, health, and environmental neighborhood conditions developed in 2024 by the Kirwan Institute for the Study of Race and Ethnicity at Ohio State University. To evaluate differences between I-STP and O-STP cohorts, P-values were calculated using both parametric and non-parametric tests, where appropriate; analysis of variance and logistic regression were employed to test multiple factors.
Results:
Significantly more individuals were tested I-STP (N=45,836) than O-STP (N=11,639). Black and White individuals were more likely to get tested I-STP, while Asian, Hispanic and individuals noted to have multiple ethnicities were more likely to get tested O-STP (p<0.005). I-STP was more likely to have high and very high SES, while individuals tested O-STP were more likely to have very low and low SES. The age of seizure onset was lower in O-STP compared to I-STP cohort (I-STP 28.24 months vs 23.29 months, p<0.0001). Individuals from I-STP had a shorter time to testing than O-STP (I-STP 16.02 months vs. O-STP 18.78 months, p<0.0001). Across both cohorts, compared to White individuals, Black and Hispanic individuals were found to have a longer time to testing (White 15.67 months; Black 16.87 months; Hispanic 17.40 months, p<0.005). The overall positive diagnostic rate was higher for O-STP than I-STP (15.94% vs 13.14%, p<0.0001). Lastly, logistic regression analysis revealed that ethnicity, sex, age of onset and time to testing all significantly affected molecular diagnosis rate.
Conclusion:
We found unexpected differences among race/ethnicity groups and SES of patients who underwent genetic testing I-STP versus O-STP, highlighting inequity among marginalized groups compared to White individuals. Our study was limited to the experience of one commercial laboratory. Though we analyzed variables known to contribute to pediatric epilepsy, additional confounding factors may be unknown. This demands further research on the relative importance of factors that affect access to genetic testing, such as provider awareness, perceived clinical utility of genetic testing, and systemic health inequities through a biopsychosocial lens. Ultimately, significantly more patients were tested I-STP and, notably, they had a shorter time from clinical diagnosis to genetic testing and a similar molecular diagnosis rate as individuals whose testing was performed O-STP.