Lopez-Medina, Ana I

ABSTRACT Drug‐induced QTc prolongation (diQTP) is a major risk factor for torsades de pointes and sudden cardiac death. This study evaluated whether carriers of the G allele of the NOS1AP rs10494366 T > G variant have greater risk for diQTP when prescribed high‐risk QT‐prolonging medications. A retrospective case‐control analysis was conducted using the Michigan Genomics Initiative (MGI) biobank, linking genotype and electronic health records for 5848 patients of European ancestry prescribed ≥ 1 CredibleMeds high‐risk drug for torsades de pointes between 2001 and 2022. QTc was Bazett‐corrected, and diQTP was defined as change of > 60 ms from the baseline QTc and/or QTc ≥ 500 ms. Associations between rs10494366 and diQTP were tested using unadjusted and propensity‐score‐adjusted logistic regression. The minor‐allele frequency (G) was 0.36, and genotype frequencies were in Hardy–Weinberg equilibrium ( p = 0.07). diQTP occurred in 12.2% of participants. The G allele was not significantly associated with risk of diQTP in either the unadjusted analysis (OR 0.94 [95% CI 0.84–1.05] p = 0.27) or the adjusted analysis (OR 0.94 [95% CI 0.83–1.06] p = 0.30). In this large, real‐world cohort of patients with European ancestry, the NOS1AP rs10494366 variant was not significantly associated with the risk of diQTP. These findings suggest that previously observed associations between this variant and baseline QTc may not extend to all drug‐induced settings.

Drug-induced QT prolongation (diQTP) can lead to rare, but potentially fatal adverse effects of many medications, yet individual susceptibility varies due to both clinical and genetic factors. SDHAF3 p.F53L (rs62624461) is a genetic variant that plays a role in mitochondrial function and was previously associated with diQTP in one small prior study. Therefore, the objective of this retrospective pharmacogenetic study was to evaluate whether SDHAF3 p.F53L is associated with clinically significant diQTP. Data were obtained from the Michigan Genomics Initiative, which links genotype information with electronic health records at Michigan Medicine. Adult patients with available genotype and electrocardiogram data who received at least one high-risk QT-prolonging drug between 2001 and 2022 were included. The analysis was limited to 5848 patients of European ancestry, of whom 320 (5.5%) were carriers of the SDHAF3 p.F53L variant. QT prolongation was defined as a QTc greater than or equal to 500 ms or an increase greater than 60 ms from baseline during high-risk QT-prolonging drug prescription. Logistic regression under a dominant genetic model assessed associations between variant carrier status and diQTP, with and without propensity score adjustment. Baseline demographics and comorbidities were similar between carriers and noncarriers. No significant association was observed between SDHAF3 p.F53L and diQTP [unadjusted odds ratio (OR) = 1.06, 95% confidence interval (CI) = 0.76–1.48, P = 0.742; adjusted OR = 1.05, 95% CI = 0.74–1.51, P = 0.773]. These results suggest that SDHAF3 p.F53L does not meaningfully influence diQTP risk in a large, real-world clinical cohort. Future studies should examine this variant across diverse populations.

Objective Drug-induced long QT syndrome (diLQTS) is an adverse reaction from over 150 FDA-approved medications, posing the risk of triggering torsades de pointes and sudden death. While common genetic variants may modestly impact QT interval individually, their collective effect can significantly amplify risk of diLQTS. Consequently, this study aimed to validate a polygenic risk score (PRS) for diLQTS previously proposed by Strauss et al. Methods A retrospective cohort study was conducted utilizing patients from the Michigan Genomics Initiative prescribed 27 high-risk QT-prolonging drugs and an ECG during the prescription. The primary outcome was marked prolongation of the QTc interval (either >60 ms change from baseline or >500 ms absolute value) during treatment with a high-risk QT-prolonging drug. Results The primary outcome occurred in 12.0% of n = 6070 self-reported White, 12.4% of 558 African American, and 8.2% of 110 Asian patients. The PRS significantly associated with diLQTS in White patients [adjusted odds ratio = 1.44 (95% CI: 1.09–1.89); P = 0.009]. However the study lacked sufficient statistical power to confirm the PRS as a risk factor in African Americans [adjusted odds ratio = 2.18 (95% CI: 0.98–5.49); P = 0.073] and Asians [adjusted odds ratio = 3.21 (95% CI: 0.69–16.87); P = 0.139] due to smaller sample sizes in these groups. Conclusion The previously published PRS for diLQTS was validated in a large, real-world cohort, demonstrating its potential as a tool for identifying high-risk patients. Incorporating this PRS into routine clinical practice could enable proactive measures to prevent life-threatening diLQTS.