Visit-to-Visit Variability of Blood Pressure and Coronary Heart Disease, Stroke, Heart Failure, and Mortality: A Cohort Study.

BACKGROUND: Variability of blood pressure (BP) across outpatient visits is frequently dismissed as random fluctuation around a patient's underlying BP. OBJECTIVE: To examine the association of visit-to-visit variability (VVV) of systolic BP (SBP) and diastolic BP with cardiovascular disease (CVD) and mortality outcomes. DESIGN: Prospective cohort study. SETTING: Post hoc analysis of ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial). PARTICIPANTS: 25 814 ALLHAT participants. MEASUREMENTS: The VVV of SBP was defined as the SD across SBP measurements obtained at 7 visits conducted from 6 to 28 months after ALLHAT enrollment. Participants without CVD events during the first 28 months of follow-up were followed from the 28-month visit through the end of active ALLHAT follow-up. Outcomes included fatal coronary heart disease (CHD) or nonfatal myocardial infarction, all-cause mortality, stroke, and heart failure. RESULTS: During follow-up, 1194 fatal CHD or nonfatal MI events, 1948 deaths, 606 strokes, and 921 heart failure events occurred. After multivariable adjustment, including for mean SBP, the hazard ratio comparing participants in the highest versus lowest quintile of SD of SBP (≥14.4 mm Hg vs. <6.5 mm Hg) was 1.30 (95% CI, 1.06 to 1.59) for fatal CHD or nonfatal MI, 1.58 (CI, 1.32 to 1.90) for all-cause mortality, 1.46 (CI, 1.06 to 2.01) for stroke, and 1.25 (CI, 0.97 to 1.61) for heart failure. Higher VVV of diastolic BP was also associated with CVD events and mortality. LIMITATION: Long-term outcomes were not available. CONCLUSION: Higher VVV of SBP is associated with an increased risk for CVD and mortality. Future studies should examine whether reducing VVV of BP lowers this risk. PRIMARY FUNDING SOURCE: National Institutes of Health.

Gene panels to help identify subgroups at high and low risk of coronary heart disease among those randomized to antihypertensive treatment: the GenHAT study.

OBJECTIVE: To identify panels of genetic variants that predict treatment-related coronary heart disease (CHD) outcomes in hypertensive patients on one of four different classes of initial antihypertensive treatment. The goal was to identify subgroups of individuals on the basis of their genetic profile who benefit most from a particular treatment. METHODS: Candidate genetic variants (n=78) were genotyped in 39 114 participants from Genetics of Hypertension Associated Treatment study, ancillary to Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial. Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial randomized hypertensive participants (≥55 years) to one of four treatments (amlodipine, chlorthalidone, doxazosin, lisinopril). The primary outcome was fatal CHD or nonfatal myocardial infarction (mean follow-up=4.9 years). A pharmacogenetic panel was derived within each of the four treatment groups. Receiver-operating characteristic (ROC) curves estimated the discrimination rate between those with and without a CHD event, on the basis of the addition of the genetic panel risk score. RESULTS: For each treatment group, we identified a panel of genetic variants that collectively improved the prediction of CHD to a small but statistically significant extent. Chlorthalidone (A): NOS3 rs3918226; SELE rs5361; ICAM1 rs1799969; AGT rs5051; GNAS rs7121; ROC comparison, P=0.004; Amlodipine (B): MMP1 rs1799750; Factor5 (F5) rs6025; NPPA rs5065; PDE4D rs6450512; MMP9 rs2274756; ROC comparison, P=0.006; Lisinopril (C): AGT rs5051; PON1 rs705379; MMP12 rs652438; F12 rs1801020; GP1BA rs6065; PDE4D rs27653; ROC comparison, P=0.01; Doxazosin (D): F2 rs1799963; PAI1 rs1799768; MMP7 rs11568818; AGT rs5051; ACE rs4343; MMP2 rs243865; ROC comparison, P=0.007. Each panel was tested for a pharmacogenetic effect; panels A, B, and D showed such evidence (P=0.009, 0.006, and 0.001, respectively) and panel C did not (P=0.09). CONCLUSION: Because each panel was associated with CHD in a specific treatment group but not the others, this research provides evidence that it may be possible to use gene panel scores as a tool to better assess antihypertensive treatment choices to reduce CHD risk in hypertensive individuals.

Has pharmacogenetics brought us closer to 'personalized medicine' for initial drug treatment of hypertension?

PURPOSE OF REVIEW: To describe recent advances in antihypertensive pharmacogenetics and discuss challenges related to translating this knowledge into 'personalized medicine' for the initial drug treatment of hypertension. RECENT FINDINGS: Recent studies included both prospective and retrospective analyses ranging from small clinical investigations of 42 participants to large, multicenter, randomized, outcome-based clinical trials of nearly 40 000 individuals. Treatment with drugs from five classes of antihypertensives was evaluated in these studies. The duration of treatment ranged from week-long follow up for blood pressure response to a decade-long follow up for clinical outcomes. In total, associations with 12 different candidate genes were assessed. These studies present the now familiar mixture of significant and nonsignificant pharmacogenetic findings that are sometimes consistent with, sometimes inconsistent with, previous findings in antihypertensive pharmacogenetics. SUMMARY: Recent research in antihypertensive pharmacogenetics has added to the existing evidence base, and novel genes and variants as well as new methodologies are cause for continued optimism. However, translation of genomic science to clinical settings has not kept pace with growing interest in personalized medicine for hypertension. New research paradigms may be needed to translate pharmacogenetics into clinical tools. Clinical application will also require a trained clinical workforce, validated genetic tests, and payers willing to fund pretreatment testing.

A review of the role of atrial natriuretic peptide gene polymorphisms in hypertension and its sequelae.

The natriuretic peptide precursor A (NPPA) gene, found on chromosome 1p36, encodes the precursor from which atrial natriuretic polypeptide (ANP) is derived. Due to the action of ANP, it is thought that the NPPA gene is involved in the control of blood pressure. Animal studies have shown that genetically reduced ANP concentration leads to salt-sensitive hypertension, whereas genetically increased ANP concentration leads to hypotension. These studies have encouraged researchers to search the human NPPA gene for polymorphisms that contribute to hypertension and its sequelae such as stroke and cardiovascular disease. This report provides a comprehensive review of studies exploring NPPA polymorphisms in relation to hypertension and hypertension-related outcomes.

Pharmacogenetic association of the NPPA T2238C genetic variant with cardiovascular disease outcomes in patients with hypertension.

CONTEXT: The NPPA gene codes for the precursor of atrial natriuretic polypeptide, suggesting that NPPA may modulate the efficacy of some antihypertensive drugs. OBJECTIVE: To test whether participants with minor NPPA alleles in the T2238C or G664A variants had different rates of cardiovascular disease or blood pressure (BP) changes than common allele homozygotes when treated with a diuretic vs other antihypertensive medications. DESIGN, SETTING, AND PATIENTS: Post hoc analysis of 38,462 participants with hypertension from ALLHAT, a multicenter randomized clinical trial conducted in the United States and Canada. Genotyping was performed from February 2004 to January 2005. INTERVENTION: Participants were randomly assigned to receive a diuretic (chlorthalidone; n = 13,860), a calcium antagonist (amlodipine; n = 8174), an angiotensin-converting enzyme inhibitor (lisinopril; n = 8233), or an alpha-blocker (doxazosin; n = 8195). MAIN OUTCOME MEASURE: The primary outcome measure was coronary heart disease (CHD), defined as fatal CHD or nonfatal myocardial infarction (mean follow-up, 4.9 years). Secondary outcomes were stroke, all-cause mortality, combined cardiovascular disease outcomes, and 6-month systolic and diastolic BP changes. Genotype x treatment interactions were tested where genotypes were modeled additively and dominantly. RESULTS: Depending on genotype, the event rates per 1000 person-years were 15.3 to 19.7 for CHO, 9.6 to 15.4 for stroke, and 27.4 to 30.7 for all-cause mortality. For the NPPA T2238C variant, lower event rates were found for the C allele carriers than for the TT homozygous individuals when comparing chlorthalidone and amlodipine (CHD: CC = 0.86; TC = 0.90; TT = 1.09; P = .03 [dominant model]; stroke: CC = 1.18; TC = 0.82; TT = 1.26; P = .01 [additive and dominant models]; all-cause mortality: CC = 0.87; TC = 0.98; TT = 1.12; P = .05 [dominant model]). Combined end points yielded similar results. Consistent with these clinical findings, 6-month changes in systolic BP for those with the CC genotype showed larger reductions with chlorthalidone (-6.5 mm Hg) than with amlodipine (-3.8 mm Hg), lisinopril (-2.4 mm Hg), or doxazosin (-3.8 mm Hg). Among those with the TT genotype, systolic BP differences between drugs were less (range, -5.4 to -7.5 mm Hg; P value, <.001 to .003 for interaction); diastolic BP showed similar results. We found no pharmacogenetic associations with the NPPA G664A variant. CONCLUSIONS: The NPPA T2238C variant was associated with modification of antihypertensive medication effects on cardiovascular disease and BP. Minor C allele carriers experienced more favorable cardiovascular disease outcomes when randomized to receive a diuretic, whereas TT allele carriers had more favorable outcomes when randomized to receive a calcium channel blocker.

Sex-specific effects of ACE I/D and AGT-M235T on pulse pressure: the HyperGEN Study.

Evidence shows that an elevated pulse pressure (PP) may lead to an increased risk of cardiovascular morbidity and mortality. There is also evidence that PP is a sexually dimorphic trait, and that genetic factors influence inter-individual variation in PP. The aim of this project was to assess the genotype-by-sex interaction on PP in a sample of mostly hypertensive African American and White participants using candidate genes involved in the renin-angiotensin-aldosterone system. Subjects were participants in the HyperGEN Study, including men (43%) and women (57%) over the age of 55 years (mean age = 65). Candidate gene polymorphisms used were ACE insertion/deletion (1,789 subjects genotyped) and AGT-M235T (1,800 subjects genotyped). We employed linear regression methods to assess the genotype-by-sex interaction. For ACE, genotype-by-sex interaction on PP was detected (P = 0.04): the "D/D" genotype predicted a 2.2 mmHg higher pulse pressure among women, but a 1.2 mmHg lower PP among men, compared to those with an "I" allele, after adjusting for age, weight, height, ethnicity, and antihypertension medication use. A similar interaction was found for systolic blood pressure. The genotype-by-sex interaction was consistent across ethnicity. The interaction was evident among those on antihypertensive medications (P = 0.05), but not among those not taking such medications (P = 0.55). In our analysis of AGT, no evidence of a genotype-by-sex interaction affecting PP, SBP, or DBP was detected. This evidence for a genotype-by-sex interaction helps our understanding of the complex genetic underpinnings of blood pressure phenotypes.

A whole genome scan for pulse pressure/stroke volume ratio in African Americans: the HyperGEN study.

BACKGROUND: Arterial stiffness is reported in numerous family studies to be heritable. Linkage analysis has identified genomic regions that likely harbor genes contributing to its phenotypic expression. We sought to identify loci contributing to arterial stiffness in a large group of African-American hypertensive families. METHODS: We performed a genome scan on 1251 African Americans in families participating in the HyperGEN (Hypertension Genetic Epidemiology Network) study. Children of the hypertensive proband generation were also included in the analysis. Arterial stiffness was estimated as pulse pressure (PP; systolic - diastolic blood pressure [BP]) divided by echocardiographically determined stroke volume (SV). The PP/SV ratio was adjusted for several nongenetic sources of variation, including demographic and lifestyle factors. The residual phenotype was analyzed using multipoint variance components linkage implemented in SOLAR 2.0.3. RESULTS: Arterial stiffness was 20% heritable in African Americans. Two regions were highly suggestive of linkage, one between markers D1S1665 and D1S1728 in the 215-cM region of chromosome 1 (LOD = 3.08), and another between D14S588 and D14S606 in the 85-cM region of chromosome 14 (LOD = 2.42). Two candidate genes (GPR-25, SMOC-1) are located in the linked regions. SMOC-1 is of physiological interest because it codes a secreted glycoprotein with five domains, each containing regions homologous to those on other proteins that mediate cell-matrix interactions. GPR-25 is homologous to receptors involved in BP regulation. CONCLUSIONS: At least two chromosomal regions in humans are likely to harbor genes contributing to interindividual variation in PP/SV ratio, an index of arterial stiffness, in African Americans.

Visit-to-Visit Variability of BP and CKD Outcomes: Results from the ALLHAT.

BACKGROUND AND OBJECTIVES: Increased visit-to-visit variability of BP is associated with cardiovascular disease risk. We examined the association of visit-to-visit variability of BP with renal outcomes among 21,245 participants in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We measured mean BP and visit-to-visit variability of BP, defined as SD, across five to seven visits occurring 6-28 months after participants were randomized to chlorthalidone, amlodipine, or lisinopril. The composite outcome included incident ESRD after assessment of SD of systolic BP or ≥50% decline in eGFR between 24 months and 48 or 72 months after randomization. We repeated the analyses using average real variability and peak value of systolic BP and for visit-to-visit variability of diastolic BP. RESULTS: Over a mean follow-up of 3.5 years, 297 outcomes occurred. After multivariable adjustment, including baseline eGFR and mean systolic BP, the hazard ratios for the composite end point were 1.29 (95% confidence interval [95% CI], 0.75 to 2.22), 1.76 (95% CI, 1.06 to 2.91), 1.46 (95% CI, 0.88 to 2.45), and 2.05 (95% CI, 1.25 to 3.36) for the second through fifth (SD of systolic BP =6.63-8.82, 8.83-11.14, 11.15-14.56, and >14.56 mmHg, respectively) versus the first (SD of systolic BP <6.63 mmHg) quintile of SD of systolic BP, respectively (P trend =0.004). The association was similar when ESRD and a 50% decline in eGFR were analyzed separately, for other measures of visit-to-visit variability of systolic BP, and for visit-to-visit variability of diastolic BP. CONCLUSIONS: Higher visit-to-visit variability of BP is associated with higher risk of renal outcomes independent of mean BP.

The Association Between Antihypertensive Medication Nonadherence and Visit-to-Visit Variability of Blood Pressure: Findings From the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial.

Low adherence to antihypertensive medication has been hypothesized to increase visit-to-visit variability (VVV) of blood pressure (BP). We assessed the association between antihypertensive medication adherence and VVV of BP in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). VVV of BP was calculated using SD independent of mean, SD, and average real variability across study visits conducted 6 to 28 months after randomization. Participants who reported taking <80% of their antihypertensive medication at ≥1 study visits were categorized as nonadherent. Participants were followed up for cardiovascular events and mortality after the assessment of adherence and VVV of BP. SD independent of mean of BP was higher for nonadherent (n=2912) versus adherent (n=16 878) participants; 11.4±4.9 versus 10.5±4.5 for systolic BP; 6.8±2.8 versus 6.2±2.6 for diastolic BP (each P<0.001). SD independent of mean of BP remained higher among nonadherent than among adherent participants after multivariable adjustment (0.8 [95% confidence interval, 0.7-1.0] higher for systolic BP and 0.4 [95% confidence interval, 0.3-0.5] higher for diastolic BP]. SD and average real variability of systolic BP and diastolic BP were also higher among nonadherent than among adherent participants. Adjustment for nonadherence did not explain the association of VVV of BP with higher fatal coronary heart disease or nonfatal myocardial infarction, stroke, heart failure, or mortality risk. In conclusion, improving medication adherence may lower VVV of BP. However, VVV of BP is associated with cardiovascular outcomes independent of medication adherence.

A genome scan for linkage with aortic root diameter in hypertensive African Americans and whites in the Hypertension Genetic Epidemiology Network (HyperGEN) study.

BACKGROUND: Aortic root dilation is a prominent feature in several cardiovascular diseases. This study seeks to identify genomic regions linked to variation in the aortic root diameter (ARD) in hypertensive African American and white individuals. METHODS: We performed a genome scan for ARD in the Hypertension Genetic Epidemiology Network Study, one of four networks in the National Heart, Lung, and Blood Institute Family Blood Pressure Program (FBPP). Data were collected from 1129 African American siblings from 504 hypertensive sibships and 883 white siblings from 374 hypertensive sibships. Standardized residual values of ARD were calculated using linear regression, adjusting for effects of age, age2, and field center (ie, minimally adjusted model), separately in groups composed by sex and ethnicity. The ARD was additionally adjusted for height, weight, diastolic BP, and systolic BP in a fully adjusted model. Multipoint linkage analysis was performed using the GENEHUNTER2 variance components method. RESULTS: Suggestive evidence for linkage was found on chromosome 5 at 85 cM in African Americans, with a maximal log of the odds (LOD) score of 2.07. Suggestive evidence for linkage was found on chromosome 1 at 157 cM in whites, with a maximal LOD score of 2.40. CONCLUSIONS: Our findings suggest that genes present on chromosomes 1 and 5 might influence inter-individual variation in aortic root diameter.

Hemodynamic and echocardiographic profiles in African American compared with White offspring of hypertensive parents: the HyperGEN study.

BACKGROUND: Alterations in cardiovascular structure and function have been shown to precede the finding of elevated blood pressure. METHODS: This study is part of the Hypertension Genetic Epidemiologic Network (HyperGEN) in which genetic and environmental determinants of hypertension were investigated in 5 geographical field centers. All nonhypertensive offspring (n = 1,035) were included from the entire HyperGEN study population that consists of 2,225 hypertensive patients and 1,380 nonhypertensive patients who had adequate echocardiographic left ventricular (LV) mass measurements. Participants were compared by self-declared race (African American and white). RESULTS: Nonhypertensive African American offspring were younger (aged 31 years vs. 38 years), more likely to be female, and had a higher body mass index (BMI) and higher systolic blood pressure (SBP) than their white counterparts. After adjusting for age, sex, SBP, pulse pressure (PP), BMI, diabetes status, and family effects, we observed statistically significant and potentially pathophysiological differences (all with P ≤ 0.001) with greater LV mass/height, relative wall thickness, and posterior wall thickness and with lesser midwall shortening, PP/stroke volume, and (PP/stroke volume)/fat-free body mass. CONCLUSION: This study shows that ethnic differences in hemodynamic and echocardiographic profiles exist in a large, population-based cohort of nonhypertensive offspring of hypertensive parents.

Effect of chlorthalidone, amlodipine, and lisinopril on visit-to-visit variability of blood pressure: results from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial.

Few randomized trials have compared visit-to-visit variability (VVV) of systolic blood pressure (SBP) across drug classes. The authors compared VVV of SBP among 24,004 participants randomized to chlorthalidone, amlodipine, or lisinopril in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). VVV of SBP was calculated across 5 to 7 visits occurring 6 to 28 months following randomization. The standard deviation (SD) of SBP was 10.6 (SD=5.0), 10.5 (SD=4.9), and 12.2 (SD=5.8) for participants randomized to chlorthalidone, amlodipine, and lisinopril, respectively. After multivariable adjustment including mean SBP across visits and compared with participants randomized to chlorthalidone, participants randomized to amlodipine had a 0.36 (standard error [SE]: 0.07) lower SD of SBP and participants randomized to lisinopril had a 0.77 (SE=0.08) higher SD of SBP. Results were consistent using other VVV of SBP metrics. These data suggest chlorthalidone and amlodipine are associated with lower VVV of SBP than lisinopril.

The effects of angiotensinogen gene polymorphisms on cardiovascular disease outcomes during antihypertensive treatment in the GenHAT study.

Previous studies have reported that risk of cardiovascular morbidity and mortality substantially increases in hypertensive patients, especially among those with inadequate blood pressure control. Two common antihypertensive drug classes including thiazide diuretics and angiotensin-converting enzyme (ACE) inhibitors affect different enzymes in the renin-angiotensin-aldosterone system (RAAS). In the RAAS, angiotensinogen is converted into angiotensin II which increases blood pressure through vasoconstriction. Using a case-only design with 3448 high-risk hypertensive individuals from the Genetics of Hypertension Associated Treatment (GenHAT) study, we examined whether seven single nucleotide polymorphisms (SNPs) in the angiotensinogen gene (AGT) interact with three classes of antihypertensive drugs including chlorthalidone (a thiazide diuretic), lisinopril (an ACE inhibitor), and amlodipine (a calcium channel blocker) to modify the risk of incident coronary heart disease (CHD) and heart failure (HF) among Caucasian and African American participants, separately. We found no gene by treatment interactions to be statistically significant after correction for multiple testing. However, some suggestive results were found. African American participants with the minor allele of rs11122576 had over two-fold higher risk of CHD when using chlorthalidone compared to using amlodipine, or lisinopril compared to amlodipine (p = 0.006 and p = 0.01, respectively). Other marginal associations are also reported among both race groups. The findings reported here suggest that rs11122576 could contribute to future personalization of antihypertensive treatment among African Americans though more studies are needed.

Genetic and Adverse Health Outcome Associations with Treatment Resistant Hypertension in GenHAT.

Treatment resistant hypertension (TRH) is defined as uncontrolled hypertension (HTN) despite the use of ≥3 antihypertensive medication classes or controlled HTN while treated with ≥4 antihypertensive medication classes. Risk factors for TRH include increasing age, diminished kidney function, higher body mass index, diabetes, and African American (AA) race. Importantly, previous studies suggest a genetic role in TRH, although the genetics of TRH are largely understudied. With 2203 treatment resistant cases and 2354 treatment responsive controls (36% AA) from the Genetics of Hypertension Associated Treatment Study (GenHAT), we assessed the association of 78 candidate gene polymorphisms with TRH status using logistic regression. After stratifying by race and adjusting for potential confounders, there were 2 genetic variants in the AGT gene (rs699, rs5051) statistically significantly associated with TRH among white participants. The Met allele of rs699 and the G allele of rs5051 were positively associated with TRH: OR = 1.27 (1.12-1.44), P = 0.0001, and OR = 1.36 (1.20-1.53), P < 0.0001, respectively. There was no similar association among AA participants (race interaction P = 0.0004 for rs699 and P = 0.0001 for rs5051). This research contributes to our understanding of the genetic basis of TRH, and further genetic studies of TRH may help reach the goal of better clinical outcomes for hypertensive patients.

Pharmacogenetic association of NOS3 variants with cardiovascular disease in patients with hypertension: the GenHAT study.

Nitric oxide synthase 3 (NOS3) catalyzes production of NO in the endothelium and may play a role in cardiovascular disease (CVD). We assessed the pharmacogenetic associations of three NOS3 polymorphisms and three antihypertensive drugs with CVD outcomes. Hypertensive subjects (n = 30,280) from a multi-center, double-blind clinical trial were randomized to chlorthalidone, amlodipine, or lisinopril treatment (mean follow up, 4.9 years). Outcomes included coronary heart disease (CHD: fatal CHD and nonfatal myocardial infarction); stroke; heart failure (fatal, requiring hospitalization, or outpatient treatment); all-cause mortality; and end-stage renal disease (ESRD). Main effects of NOS3 variants on outcome and genotype-treatment interactions were tested. For NOS3 -690 C>T (rs3918226), a higher hazard ratio (HR) was found in minor allele carriers for CHD (CC = 1.00, CT+TT = 1.12 (95% confidence interval (CI) = 1.00-1.26), P = 0.048). For NOS3 -922 A>G (rs1800779), a higher HR was found in minor allele carriers for heart failure (AA = 1.00, AG+GG = 1.10 (CI = 1.00-1.21), P = 0.046). Significant pharmacogenetic findings were observed for stroke and all-cause mortality. For -690 C>T, a lower HR was observed for stroke in minor allele carriers when treated with amlodipine versus lisinopril (CC = 0.85 (CI = 0.73-0.99), CT+TT = 0.49 (CI = 0.31-0.80), P = 0.04). For glu298asp G>T (rs1799983), a lower HR was observed for all-cause mortality in minor allele carriers when treated with amlodipine versus lisinopril (GG = 1.01 (CI = 0.91-1.13), GT+TT = 0.85 (CI = 0.75-0.97), P = 0.04). We observed significant associations with NOS3 variants and CHD and heart failure and significant pharmacogenetic effects for stroke and all cause mortality. This suggests that NOS3 variants may potentially provide useful clinical information with respect to treatment decisions in the future.

Pharmacogenetic associations of MMP9 and MMP12 variants with cardiovascular disease in patients with hypertension.

OBJECTIVES: MMP-9 and -12 function in tissue remodeling and may play roles in cardiovascular disease (CVD). We assessed associations of four MMP polymorphisms and three antihypertensive drugs with cardiovascular outcomes. METHODS: Hypertensives (n = 42,418) from a double-blind, randomized, clinical trial were randomized to chlorthalidone, amlodipine, lisinopril, or doxazosin treatment (mean follow up, 4.9 years). The primary outcome was coronary heart disease (CHD). Secondary outcomes included combined CHD, all CVD outcomes combined, stroke, heart failure (HF), and mortality. Genotype-treatment interactions were tested. RESULTS: There were 38,698 participants genotyped for at least one of the polymorphisms included here. For MMP9 R668Q (rs2274756), lower hazard ratios (HRs) were found for AA subjects for most outcomes when treated with chlorthalidone versus amlodipine (eg., CCHD: GG = 1.00, GA = 1.01, AA = 0.64; P = 0.038). For MMP9 R279Q (rs17576), modest pharmacogenetic findings were observed for combined CHD and the composite CVD outcome. For MMP12 N122S (rs652438), lower HRs were observed for CHD in subjects carrying at least one G allele and being treated with chlorthalidone versus lisinopril (CHD: AA = 1.07, AG = 0.80, GG = 0.49; P = 0.005). In the lisinopril-amlodipine comparison, higher HRs were observed for participants having at least one G allele at the MMP12 N122S locus (CHD: AA = 0.94, AG = 1.19, GG = 1.93; P = 0.041). For MMP12 -82A>G (rs2276109), no pharmacogenetic effect was found for the primary outcome, although lower HRs were observed for AA homozygotes in the chlorthalidone-amlodipine comparison for HF (P = 0.015). CONCLUSIONS: We observed interactions between antihypertensive drugs and MMP9 and MMP12 for CHD and composite CVD. The data suggest that these genes may provide useful clinical information with respect to treatment decisions.

Pharmacogenetic association of hypertension candidate genes with fasting glucose in the GenHAT Study.

BACKGROUND: Several clinical studies report increased risk of diabetes mellitus with pharmacologic treatment for hypertension (HTN). HTN genes may modify glycemic response to antihypertensive treatment. METHOD: The current study examined the association of 24 single nucleotide polymorphisms (SNPs) in 11 HTN candidate genes with fasting glucose measured at 2, 4, and 6 years after treatment initiation. The study sample included participants free of diabetes at baseline in the Genetics of Hypertension Associated Treatment (GenHAT) study (N = 9309). GenHAT participants were randomized to receive treatment with a diuretic (chlorthalidone), calcium channel blocker (amlodipine), or angiotensin-converting enzyme (ACE) inhibitor (lisinopril). Mixed models for repeated measures were employed to test for gene and pharmacogenetic associations with fasting glucose during follow-up. RESULTS: Fasting glucose at year 2 increased on average 6.8, 4.8 and 3.0 mg/dl from baseline in the chlorthalidone, amlodipine and lisinopril groups, respectively. Carrying the I allele (rs1799752) of the ACE I/D polymorphism was associated with lower fasting glucose levels (P = 0.02). Additionally, an ACE promoter polymorphism (-262, rs4291) was associated with lower fasting glucose for the model AA/AT vs. TT, which remained significant after correction for multiple testing (P = 0.001). Finally, a SNP in the α-subunit of the amiloride-sensitive epithelial sodium channel (SCNN1A, rs2228576) modified the association of amlodipine vs. chlorthalidone treatment with fasting glucose (P < 0.001). CONCLUSION: Further examination of these genes and their relationships with cardiometabolic disease could foster development of pharmacogenetic guidelines aimed to prevent increases in fasting glucose during antihypertensive treatment.

Antihypertensive pharmacogenetic effect of fibrinogen-beta variant -455G>A on cardiovascular disease, end-stage renal disease, and mortality: the GenHAT study.

OBJECTIVE: The FGB gene codes for fibrinogen-beta, a polypeptide of the coagulation factor fibrinogen, which is positively associated with cardiovascular diseases. Studies show that angiotensin-converting enzyme (ACE) inhibitors lower plasma fibrinogen concentrations, whereas diuretics and calcium-channel blockers do not. As carriers of the FGB-455 minor 'A' allele have higher levels of fibrinogen while ACE inhibitors lower it, we hypothesize that 'A' allele carriers benefit more from antihypertensive treatment with ACE inhibitors than calcium-channel blockers or diuretics, relative to 'GG' genotype individuals. METHODS: The Genetics of Hypertension Associated Treatment (GenHAT) study [ancillary to Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)] genotyped hypertensive participants for several hypertension-related candidate genes, making this a post-hoc analysis of a randomized trial. In total, 90.1% of the ALLHAT population was successfully genotyped for FGB-455. We included participants (n=30 076) randomized to one of three antihypertensive medications (lisinopril, amlodipine, chlorthalidone), with two treatment comparisons: lisinopril versus chlorthalidone and lisinopril versus amlodipine. The primary outcome of ALLHAT/GenHAT was coronary heart disease, defined as fatal coronary heart disease or non-fatal myocardial infarction, and secondary outcomes included stroke, heart failure, all-cause mortality, and end-stage renal disease (ESRD) with mean follow-up time of 4.9 years. Genotype-by-treatment interactions (pharmacogenetic effects) were tested with the Cox regression. RESULTS: Stroke: common 'GG' homozygotes had higher risk on lisinopril versus amlodipine [hazard ratio (HR)=1.38, P<0.001], whereas minor 'A' allele carriers had slightly lower risk (HR=0.96, P=0.76; P value for interaction=0.03). Mortality: 'GG' homozygotes had higher risk on lisinopril versus amlodipine (HR=1.12, P=0.02) or chlorthalidone (1.05, P=0.23), whereas 'A' allele carriers had slightly lower risk (HR=0.92, P=0.33 for lisinopril versus amlodipine; HR=0.88, P=0.08 for lisinopril versus chlorthalidone; P value for interactions 0.04 and 0.03, respectively). ESRD: 'GG' homozygotes had higher risk on lisinopril versus chlorthalidone (HR=1.27, P=0.08), whereas 'A' allele carriers had lower risk (HR=0.64, P=0.12; P value for interaction=0.03). CONCLUSION: There was evidence of pharmacogenetic effects of FGB-455 on stroke, ESRD, and mortality, suggesting that relative to those homozygous for the common allele, variant allele carriers of the FGB gene at position -455 have a better outcome if randomized to lisinopril than chlorthalidone (for mortality and ESRD) or amlodipine (for mortality and stroke). For the models in which a pharmacogenetic effect was observed, the outcome rates among 'GG' homozygotes were higher in those randomized to lisinopril versus amlodipine or chlorthalidone, whereas minor 'A' allele carriers had lower event rates when randomized to lisinopril versus the other medications.

The effect of nine common polymorphisms in coagulation factor genes (F2, F5, F7, F12 and F13 ) on the effectiveness of statins: the GenHAT study.

BACKGROUND: Pharmacogenetic research has shown that genetic variation may influence statin responsiveness. Statins exert a variety of beneficial effects beyond lipid lowering, including antithrombotic effects, which contribute to the risk reduction of cardiovascular disease. Statins have been shown to influence the expression of coagulation factors II, V, VII, XII and XIII. AIM: Data from a large randomized clinical trial of pravastatin, designed to show efficacy relative to usual care, were used to investigate whether a pharmacogenetic effect of polymorphisms in genes coding for coagulation factors II, V, VII, XII and XIII is associated with reduced fatal coronary heart disease (CHD) and nonfatal myocardial infarction, combined CHD and all-cause mortality. METHODS: The Genetics of Hypertension Associated Treatment is an ancillary study of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. The genotyped population in the lipid-lowering trial of Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial included 9624 participants randomly assigned to pravastatin or to usual care. The efficacy of pravastatin in reducing risk of all-cause mortality, CHD and nonfatal myocardial infarction and combined CHD, was compared among genotype strata by examining an interaction term in a proportional hazards model. RESULTS: None of the polymorphisms were associated with the clinical outcomes. For the F7 (-323) ins/del polymorphism there was no interaction with pravastatin for either outcome. For both the F5 Arg506Gln G>A (rs6025) polymorphism and F7 Arg353Gln G>A (rs6046) polymorphism there were no interactions with pravastatin in relation to all-cause mortality, but there were significant interactions with combined CHD [interaction hazard ratio = 1.33, 95% confidence interval (1.01-1.76) and interaction hazard ratio = 1.92, 95% confidence interval (1.00-3.65), respectively]. There were no interactions between the polymorphisms in the other coagulation genes and pravastatin in relation to any outcome. CONCLUSION: Polymorphisms in anticoagulation genes (F5 and F7) seem to modify the efficacy of pravastatin in reducing risk of cardiovascular events.

Genome-wide linkage analysis for loci affecting pulse pressure: the Family Blood Pressure Program.

Pulse pressure, the difference between systolic and diastolic blood pressure, is an independent risk factor for cardiovascular disease. Increased pulse pressure reflects reduced compliance of arteries and is a marker of atherosclerosis. To locate genes that affect pulse pressure, a genome-wide linkage scan for quantitative trait loci influencing pulse pressure was performed using variance components methods as implemented in sequential oligogenic linkage analysis routines. The analysis sample included 10 798 participants in 3320 families who were recruited as part of the Family Blood Pressure Program and were phenotyped with an oscillometric blood pressure measurement device using a consistent protocol across centers. Pulse pressure was adjusted for the effects of sex, age, age2, age-by-sex interaction, age2-by-sex interaction, body mass index, and field center to remove sources of variation other than the genetic effects related to pulse pressure. Significant linkage was observed on chromosome 18 (logarithm of odds [LOD]=3.2) in a combined racial sample, chromosome 20 (LOD=4.4), and 17 (LOD=3.6) in Hispanics, chromosome 21 (LOD=4.3) in whites, chromosome 19 (LOD=3.1) in a combined sample of blacks and whites, and chromosome 7 (logarithm of odds [LOD]=3.1) in blacks from the GenNet Network. Our genome scan shows significant evidence for linkage for pulse pressure in multiple areas of the genome, supporting previous published linkage studies. The identification of these loci for pulse pressure and the apparent congruence with other blood pressure phenotypes provide increased support that these regions contain genes influencing blood pressure phenotypes.