Hypoglycemia is a preventable adverse effect of treatment in diabetes patients, but actionable pharmacogenetic evidence to minimize hypoglycemia risk is lacking. We used the MVP biospecimen and clinical biobank to perform a case/control GWAS of hypoglycemia in 96,406 diabetes patients receiving care in the U.S. Veterans Health Administration. Cases had an outpatient random plasma glucose (RPG) <70 mg/dL or an emergency room visit for hypoglycemia; controls had an RPG or clinic visit annually during follow-up but did not meet the case criteria. Genotypes were based on a custom MVP Affymetrix array, imputed with ancestry-specific HRC reference panels and limited to variants with minor allele frequency (MAF) >1%. GWAS were conducted in 72,244 participants (22,045 cases) of European ancestry [EUR] and 24,162 (10,441 cases) of African ancestry [AFR]), adjusted for age at MVP enrollment, sex, and 10 genetic principal components. We identified a single locus associated with hypoglycemia in EUR individuals (rs1064173, HLA-DQB1 locus, odds ratio [OR] 1.15, p=5.6E-19, MAF 0.20) and in AFR individuals (rs12712928, SIX3 locus, OR 0.87, p=2.7E-8, MAF 0.17). In a phenomewide association study (PheWAS) in MVP EUR diabetes patients, rs1064173 was associated with type 1 diabetes (T1D, OR 1.41, p=7.8E-25) and diabetes complications (retinopathy, OR 1.24, p=9E-24; neuropathy, OR 1.16, p=1.3E-5). To address the known association of the HLA locus with T1D, we performed a sensitivity analysis excluding patients with any use of T1D diagnosis codes. In this sample enriched for type 2 diabetes, rs1064173 remained nominally associated with hypoglycemia (OR 1.23, p=0.02) and retinopathy (OR 1.10, p=0.003). Rs12712928 - previously associated with glucose and hemoglobin A1c in an East Asian sample - was not associated with any diagnoses in a PheWAS of MVP AFR diabetes patients.

In conclusion, a GWAS of hypoglycemia in a clinical biobank found ancestry-specific genetic associations that may have treatment implications.

Disclosure

S. Raghavan: None. Z. Wang: None. A.M. Hung: None. B.R. Charest: None. L. Costa: None. E.M. Litkowski: None. A. Leong: None. J.B. Meigs: Consultant; Self; Quest Diagnostics. P.W. Wilson: None. P. Reaven: Consultant; Self; Boston Heart Diagnostics, Intercept Pharmaceuticals, Inc. Research Support; Self; Bristol-Myers Squibb, Lysulin. M.K. Rhee: Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc. Y.V. Sun: None. L.S. Phillips: Research Support; Self; AbbVie Inc., Diasome Pharmaceuticals, Inc., Eli Lilly and Company, GlaxoSmithKline plc., Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Pfizer Inc., Sanofi-Aventis. Other Relationship; Self; Diasyst, Janssen Pharmaceuticals, Inc.

Funding

U.S. Department of Veterans Affairs (I01-CX001737, IK2-CX001907-01)

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.