Genome-Wide Association Study of Hypoglycemia in Adults With Diabetes in the Million Veteran Program

Hypoglycemia is a preventable adverse treatment effect in diabetes patients, but genetic markers to identify those with increased susceptibility are lacking. We performed a case/control genome-wide association study (GWAS) of hypoglycemia in U.S. Million Veteran Program (MVP) participants with medication-treated diabetes. Case participants had an outpatient random serum/plasma glucose <70 mg/dL or an emergency department visit for hypoglycemia. GWAS was stratified by race/ethnicity, adjusted for age at MVP enrollment, sex, and top 10 population-specific principal components, followed by multipopulation meta-analysis. Secondary analyses examined genetic associations with hypoglycemia stratified by diabetes medication exposure as well as replication in UK Biobank and the Action to Control Cardiovascular Risk in Diabetes clinical trial. The study included 72,244 (22,045 case participants) non-Hispanic White participants, 24,162 (10,441 case participants) non-Hispanic Black participants, and 9,196 (2,800 case participants) Hispanic participants. Four loci had genome-wide significant associations with hypoglycemia in multipopulation meta-analysis: rs12712928 (chromosome 2, SIX2/SIX3 locus), rs1064173 (chromosome 6, HLA-DQB1/DQA2 locus), rs35198068 (chromosome 10, TCF7L2 locus), and rs113748381 (chromosome 17, SCL16A11 locus). All four loci replicated in at least one independent cohort, and the magnitude of associations with hypoglycemia varied by diabetes type. Genome-wide analyses may complement candidate pharmacogenetic studies to identify risk markers of adverse drug effects. Article Highlights Genetic variants associated with hypoglycemia risk in individuals with medication-treated diabetes have not been evaluated genome-wide. The specific question we asked was whether common genetic variants are associated with hypoglycemia among individuals with diabetes treated with glucose-lowering medications. We found four genomic loci were associated with hypoglycemia in a genome-wide association study. One locus—on chromosome 6—was associated with hypoglycemia only in individuals with likely type 1 diabetes, and two loci—on chromosome 2 and chromosome 6—were associated with hypoglycemia only in the context of treatment with sulfonylureas (chromosome 2) or with insulin (chromosome 6). Genetic variants may help identify individuals with diabetes at increased hypoglycemia risk, but additional study is needed to address the clinical utility of genetic data to inform hypoglycemia risk.