A Genetic Response Score for Hydrochlorothiazide Use: Insights From Genomics and Metabolomics Integration

Abstract

Hydrochlorothiazide is among the most commonly prescribed antihypertensives; yet, <50% of hydrochlorothiazide-treated patients achieve blood pressure (BP) control. Herein, we integrated metabolomic and genomic profiles of hydrochlorothiazide-treated patients to identify novel genetic markers associated with hydrochlorothiazide BP response. The primary analysis included 228 white hypertensives treated with hydrochlorothiazide from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) study. Genome-wide analysis was conducted using Illumina Omni 1 mol/L-Quad Chip, and untargeted metabolomics was performed on baseline fasting plasma samples using a gas chromatography-time-of-flight mass spectrometry platform. We found 13 metabolites significantly associated with hydrochlorothiazide systolic BP (SBP) and diastolic BP (DBP) responses (false discovery rate, <0.05). In addition, integrating genomic and metabolomic data revealed 3 polymorphisms (rs2727563 PRKAG2, rs12604940 DCC, and rs13262930 EPHX2) along with arachidonic acid, converging in the netrin signaling pathway (P=1×10(-5)), as potential markers, significantly influencing hydrochlorothiazide BP response. We successfully replicated the 3 genetic signals in 212 white hypertensives treated with hydrochlorothiazide and created a response score by summing their BP-lowering alleles. We found patients carrying 1 response allele had a significantly lower response than carriers of 6 alleles (∆SBP/∆DBP: -1.5/1.2 versus -16.3/-10.4 mm Hg, respectively, SBP score, P=1×10(-8) and DBP score, P=3×10(-9)). This score explained 11.3% and 11.9% of the variability in hydrochlorothiazide SBP and DBP responses, respectively, and was further validated in another independent study of 196 whites treated with hydrochlorothiazide (DBP score, P=0.03; SBP score, P=0.07). This study suggests that PRKAG2, DCC, and EPHX2 might be important determinants of hydrochlorothiazide BP response.

Keywords: genome-wide association study; hydrochlorothiazide; hypertension; metabolomics; pharmacogenetics.

Figure 1. The overall analyses framework of the study

Figure 2. Effects of rs2727563 and rs12604940 polymorphisms on the BP responses of whites treated with HCTZ in the PEAR HCTZ monotherapy and HCTZ add-on

A) rs2727563 on SBP responses in PEAR monotherapy and PEAR HCTZ add-on. B) rs2727563 on DBP response in the PEAR monotherapy and PEAR HCTZ add-on. C) rs12604940 on SBP response in PEAR monotherapy and PEAR HCTZ add-on. D) rs12604940 on DBP response in the PEAR monotherapy and PEAR HCTZ add-on. BP responses were adjusted for baseline BP, age, sex, and principal components 1 and 2. P-values represented are for contrast of adjusted means between different genotype groups. Error bars represent standard error of the mean. *One sided p-value based on a one-sided hypothesis tested in the replication study.

Figure 3. Correlation between HCTZ BP response and arachidonic acid peak height

P-values and correlation coefficient (r-values) were generated using Pearson correlation test. A) systolic blood pressure. B) diastolic blood pressure. Peak height represents the maximum intensity of all data points forming the mass spectrometry peak.

Figure 4. Effects of rs13262930 polymorphism on the BP response of whites treated with HCTZ in the PEAR HCTZ monotherapy and PEAR HCTZ add-on

A) SBP response in the PEAR HCTZ monotherapy. B) DBP response in the PEAR HCTZ monotherapy. C) Replicating the effect on SBP response in the PEAR HCTZ add-on. D) Replicating the effect on DBP response in the PEAR HCTZ add-on. BP responses were adjusted for baseline BP, age, sex and principal components 1 and 2. P-values represented are for contrast of adjusted means between different genotype groups. Error bars represent standard error of the mean. *One sided p-value based on a one-sided hypothesis tested in the replication study.

Figure 5. HCTZ response score in PEAR and GERA studies

A) Tested against DBP response in the PEAR HCTZ monotherapy. B) Tested against SBP response in the PEAR HCTZ monotherapy. C) Tested against DBP response in the GERA study. D) Tested against SBP response in the GERA study. BP responses were adjusted for baseline BP, age, sex and principal components 1 and 2. P-values represented are for contrast of adjusted means between different genotype groups. Error bars represent standard error of the mean. *One sided p-value based on a one-sided hypothesis tested in the replication study.