Maternal red blood cell alloimmunization prevalence in the United States.

Hemolytic disease of fetus and newborn (HDFN) is a life-threatening disease mediated by maternal alloimmunization to red blood cell (RBC) antigens. Studies of maternal alloimmunization prevalence in the United States (U.S.) lack national data. This study describes prevalence and trends in alloimmunization in pregnancy in the U.S. RBC antibodies (abs) were identified in a large, nationwide, commercial laboratory database from 2010-2021. The cohort comprised pregnancies for which the year of lab collection and patient's state of residence were available. Data were normalized based on U.S. Centers for Disease Control and Prevention estimates of live births and weighted by year and U.S. Census Division. Cochrane-Armitage tests assessed temporal trends of alloimmunization. Of 9,876,196 pregnancies, 1.5% (147,262) screened positive for RBC abs, corresponding to an estimated prevalence of 1,518/100,000 pregnancies. Of identified RBC abs, anti-D comprised 64.1% (586/100,000 pregnancies). Prevalence of other high-risk RBC abs for HDFN included anti-K (68/100,000) and anti-c (29/100,000). Incidence of all three high-risk abs increased from 2010-21 (all p<0.001). Among almost 10 million pregnancies in the US, comprising an estimated 14.4% of all pregnancies, 1.5% screened positive for RBC abs. Almost three-quarters (74.3%; 683/100,000) of RBC abs identified were high-risk for HDFN. Though prevalence of anti-D is difficult to interpret without the ability to distinguish alloimmunization from passive immunity, it remains problematic in HDFN, ranking second only to anti-K in critical titers. Given the sequelae of HDFN, new initiatives are required to reduce the incidence of alloimmunization in patients of reproductive potential.

Plasma arginine levels in arginase deficiency in the "real world".

Background: Deficiency of arginase-1, the final enzyme in the urea cycle, causes a distinct clinical syndrome and is characterized biochemically by a high level of plasma arginine. While conventional therapy for urea cycle disorders can lower these levels to some extent, it does not normalize them. Until now, research on plasma arginine levels in this disorder has primarily relied on data from specialized tertiary centers, which limits the ability to assess the natural history and treatment efficacy of arginase-1 deficiency due to the small number of patients in each center and technical variations in plasma arginine measurements among different laboratories. Method: In this study, we reported plasma arginine levels from 51 patients with arginase-1 deficiency in the database of Quest Diagnostics. The samples were collected from different US regions. Results: The mean plasma arginine level in these treated patients was 373 µmol/L and the median level was 368.4 µmol/L. Our data set from 30 arginase deficiency patients with plasma amino acid data from five or more collections revealed significant correlations between the levels of arginine and five other amino acids (citrulline, alanine, ornithine, glutamine, and asparagine). Conclusion: Despite treatment, the arginine levels remained persistently elevated and did not change significantly with age, suggesting the current treatment regimen is inadequate to control arginine levels and underscoring the need to seek more effective treatments for this disorder.

Predictors of lack of glycemic control in persons with type 2 diabetes.

BACKGROUND: Professional guidelines recommend an HbA1c < 7% for most people with diabetes and < 8.5% for those with relaxed glycemic goals. However, many people with type 2 diabetes mellitus (T2DM) are unable to achieve the desired HbA1c goal. This study evaluated factors associated with lack of improvement in HbA1c over 3 years. METHODS: All patients with T2DM treated within a major academic healthcare system during 2015-2020, who had at least one HbA1c value > 8.5% within 3 years from their last HbA1c were included in analysis. Patients were grouped as improved glycemic control (last HbA1c ≤ 8.5%) or lack of improvement (last HbA1c > 8.5%). Multivariate logistic regression analysis was performed to assess independent predictors of lack of improvement in glycemic control. RESULTS: Out of 2,232 patients who met the inclusion criteria, 1,383 had an improvement in HbA1c while 849 did not. In the fully adjusted model, independent predictors of lack of improvement included: younger age (odds ratio, 0.89 per 1-SD [12 years]; 95% CI, 0.79-1.00), female gender (1.30, 1.08-1.56), presence of hypertension (1.29, 1.08-1.55), belonging to Black race (1.32, 1.04-1.68, White as reference), living in low income area (1.86,1.28-2.68, high income area as reference), and insurance coverage other than Medicare (1.32, 1.05-1.66). Presence of current smoking was associated with a paradoxical improvement in HbA1c (0.69, 0.47-0.99). In a subgroup analysis, comparing those with all subsequent HbA1c values > 8.5% (N = 444) to those with all subsequent HbA1c values < 8.5% (N = 341), similar factors were associated with lack of improvement, but smoking was no longer significant. CONCLUSION: We conclude that socioeconomic factors like race, type of insurance coverage and living in low-income areas are associated with lack of improvement in HbA1c over a period of 3-years in people with T2DM. Intervention strategies focused on low-income neighborhoods need to be designed to improve diabetes management.

Insulin resistance probability score and incident cardiovascular disease.

BACKGROUND: Insulin resistance (IR) is associated with cardiovascular disease (CVD). However, insulin immunoassay variability and scarce research of the elderly have hindered the adoption of IR assessment for CVD prevention. We asked whether the probability of having IR [p(IR)]-derived from insulin and C-peptide mass-spectrometry assays-was associated with CVD in the elderly. METHODS: A random cohort was drawn from MPP, a population-based study of the elderly. After excluding those with missing data, CVD, or diabetes, 3645 participants (median age = 68) remained. RESULTS: During follow-up (13.3 years), 794 incident CVD events were observed. p(IR) > 80% (n = 152) compared with p(IR) ≤ 80% was associated with incident CVD (HR = 1.51, 95% CI 1.12-2.05, p = 0.007) and CVD or all-cause mortality (HR = 1.43, 95% CI 1.16-1.77, p = 0.0009) after adjusting for age, sex, hypertension, smoking, HDL-cholesterol, total cholesterol, triglycerides, BMI, and prediabetes. CONCLUSION: High p(IR) was associated with >50% greater risk of incident CVD. IR assessment in the elderly may be warranted.

Concordance of Cardiovascular Risk Factors and Behaviors in a Multiethnic US Nationwide Cohort of Married Couples and Domestic Partners.

Importance: Married couples and domestic partners have been reported to share similar environmental exposures, adopt similar behavior patterns, and have similar transferable characteristics. However, the degree to which couples share similar levels of cardiovascular risk factors and behaviors is uncertain. Objective: To assess within-couple concordance of the American Heart Association-defined Life's Simple 7 (LS7). Design, Setting, and Participants: Cross-sectional study with a longitudinal substudy of employees and spouses (or domestic partners) who participated in an employer-sponsored health assessment program throughout the United States between October 2014 and December 2018. Data were analyzed from November 1, 2019, to August 4, 2020. Exposures: Having a spouse or domestic partner. Main Outcomes and Measures: The LS7 risk factors and behaviors (smoking status, body mass index, exercise, diet, total cholesterol, blood pressure, and fasting glucose) were assessed by questionnaires, examinations, and laboratory tests. LS7 categories were scored as 2 for ideal, 1 for intermediate, or 0 for poor and summed to generate a CV health score. Results: The study included 10 728 participants (5364 couples): 7% were African American, 11% Hispanic, 21% Asian, and 54% White (median [interquartile range] age, 50 [41-57] years for men and 47 [39-55] for women). For most couples, both members were in the ideal category or both were in a nonideal category. Concordance ranged from 53% (95% CI, 52%-54%) for cholesterol to 95% (95% CI, 94%-95%) for diet. For the CV health score, in 79% (95% CI, 78%-80%) of couples both members were in a nonideal category, which was associated mainly with unhealthy diet (94% [95% CI, 93%-94%] of couples) and inadequate exercise (53% [95% CI, 52%-55%] of couples). However, in most couples, both members were in the ideal category for smoking status (60% [95% CI, 59%-61%] of couples) and glucose (56% [95% CI, 55%-58%]). Except for total cholesterol, when 1 member of a couple was in the ideal category, the other member was likely also to be in the ideal category: the adjusted odds ratios for also being in the ideal category ranged from 1.3 (95% CI, 1.1-1.5; P ≤ .001) for blood pressure to 10.6 (95% CI, 7.4-15.3; P ≤ .001) for diet. Concordance differed by ethnicity, socioeconomic status, and geographic location. A 5-year longitudinal analysis of 2186 couples found modest changes in concordance of blood pressure (from 55% [95% CI, 53%-57%] to 59% [95% CI, 57%-61%]; P < .001 for trend) and fasting glucose (from 64% [95% CI, 62%-66%] to 59% [95% CI, 57%-61%]; P < .001 for trend) with no change in other factors. Conclusions and Relevance: In this study, high concordance of nonideal behaviors was found within couples; behavioral modification programs may benefit both the targeted and the nontargeted member of a couple.

Gaps in Dyslipidemia Care Among Working-Aged Individuals With Employer-Sponsored Health Care.

Background The American Heart Association and American College of Cardiology guidelines defined patient-management groups that would benefit from lowering of low-density lipoprotein cholesterol (LDL-C). We assessed gaps in dyslipidemia care among employees and spouses with health benefits. Methods and Results We studied 17 889 employees and spouses who were covered by an employer-sponsored health plan and participated in an annual health assessment. Using medical claims, laboratory tests, and risk assessment questionnaires, we found that 43% of participants were in one of 4 patient-management groups: secondary prevention, severe hypercholesterolemia (LDL-C ≥190 mg/dL at least once in the preceding 5 years), diabetes mellitus, or elevated 10-year risk of cardiovascular disease. To assess gaps in dyslipidemia care, we used LDL-C ≤70 mg/dL as the goal for both the secondary prevention group and those in the elevated 10-year risk group with >20% risk; LDL-C ≤100 mg/dL was used for the other groups. Among those in patient-management groups, 27.3% were in the secondary prevention group, 7.4% were in the severe hypercholesterolemia group, 29.9% were in the diabetes mellitus group, and 35.4% were in the elevated 10-year risk group. About 74% of those in patient-management groups had above-goal LDL-C levels, whereas only 31% had evidence of a lipid-lowering therapy in the past 6 months: 45% in the secondary prevention group, 31% in the severe hypercholesterolemia group, 36% in the diabetes mellitus group, and 17% in the elevated 10-year risk group. Conclusions The substantial gaps in LDL-C treatment and goal attainment among members of an employer-sponsored medical plan who were mostly aware of their LDL-C levels indicate the need for gap-closure initiatives.

LDL subfractions are associated with incident cardiovascular disease in the Malmö Prevention Project Study.

BACKGROUND AND AIMS: After assessing the risk for cardiovascular disease (CVD) based on traditional risk factors, decisions concerning lipid lowering therapy might remain uncertain. To investigate whether lipoprotein subfraction levels could aid these decisions, we assessed the association between lipoprotein subfractions and CVD, after adjustment for traditional risk factors including standard lipids. METHODS: Using a case-cohort design, participants were randomly drawn from the Malmö Prevention Project (MPP), a population-based prospective study of 18,240 participants, and supplemented with additional incident CVD events (5764 participants, 1784 CVD events). RESULTS: Low density lipoprotein particle number (LDL-P) and individual subfractions ranging in size from very-small to large were associated with CVD (continuous p value (pcont) < 0.001) while adjusting for age, sex, hypertension, smoking, and diabetes. After further adjustment for LDL-C, HDL-C, and triglycerides, very small LDL subfraction (b) (LDL-VS (b)) remained associated with CVD (HR = 1.23, 95% CI, 1.06 to 1.43 for top vs. bottom quartile, pcont = 0.03). Among participants with low/intermediate risk [without diabetes and with LDL-C <3.36 mmol/L (<130 mg/dL)], the fully adjusted HR for LDL-small (top vs. bottom quartile) was 1.48 (95% CI 1.02 to 2.17, pcont = 0.03). Among those with very-high risk (>20% 10-year risk of CVD), LDL-VS(a) and LDL-VS(b) were associated with CVD in fully adjusted models (HR = 1.37, 95% CI 1.12 to 1.67 and HR = 1.28, 95% CI 1.07 to 1.53, respectively, pcont≤0.03). CONCLUSIONS: Smaller LDL particles are associated with incident CVD independently of traditional risk factors, including standard lipids, in participants with low/intermediate and very-high risk, who might benefit from improved risk assessment.

Use of low density lipoprotein particle number levels as an aid in statin treatment decisions for intermediate risk patients: a cost-effectiveness analysis.

BACKGROUND: The 2013 ACC/AHA guideline recommended either no statin therapy or moderate-intensity statin therapy (MST) for intermediate risk patients-those with 5-7.5% 10-year risk and without cardiovascular disease (CVD), hypercholesterolemia or diabetes. The guideline further suggested that the therapy choice be based on patient-clinician discussions of risks and benefits. Since low-density lipoprotein particle (LDL-P) levels were reported to be associated with CVD independently of traditional risk factors in intermediate and low risk patients, we investigated the cost-effectiveness of using LDL-P levels to identify intermediate risk patients likely to benefit from initiating or intensifying statin therapy. METHODS: We evaluated 5 care strategies for intermediate risk patients. These included the strategies suggested by the guideline: no-statin therapy and MST. We compared each of these strategies to a related strategy that incorporated LDL-P testing. No-statin therapy was compared with the strategy of MST for those with high LDL-P levels and no statin therapy for all other patients (test-and-MST). MST was compared with the strategy of high-intensity statin therapy (HST) for those with high LDL-P levels and MST for all other patients (test-and-HST). We also evaluated the strategy of HST for all. Costs (payer perspective) and utilities were assessed over a 5-year time horizon in a Markov model of 100,000 hypothetical intermediate risk patients. RESULTS: HST dominated all other strategies, costing less and-despite causing 739 more cases of diabetes than did MST-resulting in more quality adjusted life-years (QALYs). For patient-clinician discussions that would otherwise lead to the MST strategy, we found the test-and-HST strategy reduced costs by $4.67 MM and resulted in 134 fewer CVD events and 115 additional QALYs. For patient-clinician discussions that would otherwise lead to no statin therapy, we found that the test-and-MST strategy reduced costs by $3.25 MM, resulted in 97 fewer CVD events and 44 additional QALYs. CONCLUSIONS: The HST strategy was cost saving and improved outcomes in intermediate risk patients. For patient and clinicians concerned about the adverse events associated with HST, using LDL-P levels to target intensified statin therapy could improve outcomes and reduce costs.

Risk prediction by genetic risk scores for coronary heart disease is independent of self-reported family history.

AIMS: Genetic risk scores (GRSs) have been associated with coronary heart disease (CHD) in large studies. We asked whether expanding an established 27-variant GRS (GRS27) to a 50-variant GRS (GRS50) improved CHD prediction and whether GRSs are independent of self-reported family history of CHD. METHODS AND RESULTS: The association between GRSs and incident CHD was assessed in Cox models adjusting for established risk factors in 23 595 participants of the Malmö Diet and Cancer study--a prospective, population-based study. During a median follow-up of 14.4 years, 2213 participants experienced a first CHD event. After adjustment for established risk factors, both GRS27 and GRS50 were associated with incident CHD [hazard ratio (HR) = 1.70 for high (top quintile) vs. low (bottom quintile) of GRS27; 95% confidence interval (CI): 1.48-1.94; Ptrend = 1.6 × 10(-15) and HR = 1.92 for GRS50; 95% CI: 1.67-2.20; Ptrend = 6.2 × 10(-22)]. Adding 23 single nucleotide polymorphisms (SNPs) to GRS27 improved risk prediction (P = 3 × 10(-6)). Further adjustment for self-reported family history did not appreciably change the risk estimates of either GRS27 (HR = 1.65; 95% CI: 1.45-1.89) or GRS50 (HR = 1.87; 95% CI: 1.63-2.14). The addition of GRS50 to established risk factors, including self-reported family history, improved discrimination (P < 0.0001) and reclassification (continuous net reclassification improvement index = 0.17, P < 0.0001). In young participants (below median age), those with high GRS50 had 2.4-fold greater risk (95% CI: 1.85-3.12) than those with low GRS50. CONCLUSION: The addition of 23 SNPs to an existing GRS27 improved CHD risk prediction and was independent of self-reported family history. Coronary heart disease risk assessment by GRS could be particularly useful in young individuals.

Genetic risk for atrial fibrillation could motivate patient adherence to warfarin therapy: a cost effectiveness analysis.

BACKGROUND: Atrial fibrillation (AF) increases risk of stroke, and although this stroke risk can be ameliorated by warfarin therapy, some patients decline to adhere to warfarin therapy. A prospective clinical study could be conducted to determine whether knowledge of genetic risk for AF could increase adherence to warfarin therapy for patients who initially declined therapy. As a prelude to a potential prospective clinical study, we investigated whether the use of genetic information to increase adherence could be cost effective. METHODS: Markov model assessed costs and utilities of two care strategies for AF patients who declined warfarin therapy. In the usual care strategy patients received aspirin. In the test strategy genetic risk for AF was assessed (genotype of the 4q25 locus) and some patients with a positive genetic test (≥1 risk allele) were assumed to adhere to warfarin therapy. The remaining patients received aspirin. The incremental cost-effectiveness ratio (ICER) was the ratio of the costs differential and the quality adjusted life-years (QALYs) differential for the two strategies. RESULTS: We found that the 4q25 genetic testing strategy, compared with the usual care strategy (aspirin therapy), would be cost-effective (ICER $ 47,148) if 2.1 % or more of the test positive patients were to adhere to warfarin therapy. The test strategy would become a cost saving strategy if 5.3 % or more of the test positive patients were to adhere to warfarin therapy. If 20 % of test positive patients were to adhere to warfarin therapy in a hypothetical cohort of 1000 patients, 7 stroke events would be prevented and 3 extra-cranial major bleeding events would be caused over 5 years, resulting in a cost savings of ~ $250,000 and a net gain of 9 QALYs. DISCUSSION: A clinical study to assess the impact of patient knowledge of genetic risk of AF on adherence to warfarin therapy would be merited because even a modest increase in patient adherence would make a genetic testing strategy cost-effective. CONCLUSION: Providing patients who declined warfarin therapy with information about their genetic risk of AF would be cost effective if this genetic risk information resulted in modest increases in adherence.

A gene variant in CERS2 is associated with rate of increase in albuminuria in patients with diabetes from ONTARGET and TRANSCEND.

Although albuminuria and subsequent advanced stage chronic kidney disease are common among patients with diabetes, the rate of increase in albuminuria varies among patients. Since genetic variants associated with estimated glomerular filtration rate (eGFR) were identified in cross sectional studies, we asked whether these variants were also associated with rate of increase in albuminuria among patients with diabetes from ONTARGET and TRANSCEND-randomized controlled trials of ramipril, telmisartan, both, or placebo. For 16 genetic variants associated with eGFR at a genome-wide level, we evaluated the association with annual rate of increase in albuminuria estimated from urine albumin:creatinine ratio (uACR). One of the variants (rs267734) was associated with rate of increase in albuminuria. The annual rate of increase in albuminuria among risk homozygotes (69% of the study population) was 11.3% (95%CI; 7.5% to 15.3%), compared with 5.0% (95%CI; 3.3% to 6.8%) for heterozygotes (27% of the population), and 1.7% (95%CI; -1.7% to 5.3%) for non-risk homozygotes (4% of the population); P = 0.0015 for the difference between annual rates in the three genotype groups. These estimates were adjusted for age, sex, ethnicity, and principal component of genetic heterogeneity. Among patients without albuminuria at baseline (uACR<30 mg/g), each risk allele was associated with 50% increased risk of incident albuminuria (OR = 1.50; 95%CI 1.15 to 1.95; P = 0.003) after further adjustment for traditional risk factors including baseline uACR and eGFR. The rs267734 variant is in almost perfect linkage-disequilibrium (r2 = 0.94) with rs267738, a single nucleotide polymorphism encoding a glutamic acid to alanine change at position 115 of the ceramide synthase 2 (CERS2) encoded protein. However, it is unknown whether CERS2 function influences albuminuria. In conclusion, we found that rs267734 in CERS2 is associated with rate of increase in albuminuria among patients with diabetes and elevated risk of cardiovascular disease.

Twelve-single nucleotide polymorphism genetic risk score identifies individuals at increased risk for future atrial fibrillation and stroke.

BACKGROUND AND PURPOSE: Atrial fibrillation (AF) is prevalent and there is a clinical need for biomarkers to identify individuals at higher risk for AF. Fixed throughout a life course and assayable early in life, genetic biomarkers may meet this need. Here, we investigate whether multiple single nucleotide polymorphisms together as an AF genetic risk score (AF-GRS) can improve prediction of one's risk for AF. METHODS: In 27 471 participants of the Malmö Diet and Cancer Study, a prospective, community-based cohort, we used Cox models that adjusted for established AF risk factors to assess the association of AF-GRS with incident AF and ischemic stroke. Median follow-up was 14.4 years for incident AF and 14.5 years for ischemic stroke. The AF-GRS comprised 12 single nucleotide polymorphisms that had been previously shown to be associated with AF at genome-wide significance. RESULTS: During follow-up, 2160 participants experienced a first AF event and 1495 had a first ischemic stroke event. Participants in the top AF-GRS quintile were at increased risk for incident AF (hazard ratio, 2.00; 95% confidence interval, 1.73-2.31; P=2.7×10(-21)) and ischemic stroke (hazard ratio, 1.23; 95% confidence interval, 1.04-1.46; P=0.02) when compared with the bottom quintile. Addition of the AF-GRS to established AF risk factors modestly improved both discrimination and reclassification (P<0.0001 for both). CONCLUSIONS: An AF-GRS can identify 20% of individuals who are at ≈2-fold increased risk for incident AF and at 23% increased risk for ischemic stroke. Targeting diagnostic or therapeutic interventions to this subset may prove clinically useful.

Genome-wide study of gene variants associated with differential cardiovascular event reduction by pravastatin therapy.

Statin therapy reduces the risk of coronary heart disease (CHD), however, the person-to-person variability in response to statin therapy is not well understood. We have investigated the effect of genetic variation on the reduction of CHD events by pravastatin. First, we conducted a genome-wide association study of 682 CHD cases from the Cholesterol and Recurrent Events (CARE) trial and 383 CHD cases from the West of Scotland Coronary Prevention Study (WOSCOPS), two randomized, placebo-controlled studies of pravastatin. In a combined case-only analysis, 79 single nucleotide polymorphisms (SNPs) were associated with differential CHD event reduction by pravastatin according to genotype (P<0.0001), and these SNPs were analyzed in a second stage that included cases as well as non-cases from CARE and WOSCOPS and patients from the PROspective Study of Pravastatin in the Elderly at Risk/PHArmacogenomic study of Statins in the Elderly at risk for cardiovascular disease (PROSPER/PHASE), a randomized placebo controlled study of pravastatin in the elderly. We found that one of these SNPs (rs13279522) was associated with differential CHD event reduction by pravastatin therapy in all 3 studies: P = 0.002 in CARE, P = 0.01 in WOSCOPS, P = 0.002 in PROSPER/PHASE. In a combined analysis of CARE, WOSCOPS, and PROSPER/PHASE, the hazard ratio for CHD when comparing pravastatin with placebo decreased by a factor of 0.63 (95% CI: 0.52 to 0.75) for each extra copy of the minor allele (P = 4.8 × 10(-7)). This SNP is located in DnaJ homolog subfamily C member 5B (DNAJC5B) and merits investigation in additional randomized studies of pravastatin and other statins.

The contribution of a 9p21.3 variant, a KIF6 variant, and C-reactive protein to predicting risk of myocardial infarction in a prospective study.

BACKGROUND: Genetic risk factors might improve prediction of coronary events. Several variants at chromosome 9p21.3 have been widely reported to be associated with coronary heart disease (CHD) in prospective and case-control studies. A variant of KIF6 (719Arg) has also been reported to be associated with increased risk of CHD in large prospective studies, but not in case-control studies. We asked whether the addition of genetic information (the 9p21.3 or KIF6 variants) or a well-established non-genetic risk factor (C-reactive protein [CRP]) can improve risk prediction by the Framingham Risk Score (FRS) in the Cardiovascular Health Study (CHS)--a prospective observational study of risk factors for cardiovascular disease among > 5,000 participants aged 65 or older. METHODS: Improvement of risk prediction was assessed by change in the area under the receiver-operator characteristic curve (AUC) and by net reclassification improvement (NRI). RESULTS: Among white participants the FRS was improved by addition of KIF6 719Arg carrier status among men as assessed by the AUC (from 0.581 to 0.596, P = 0.03) but not by NRI (NRI = 0.027, P = 0.32). Adding both CRP and 719Arg carrier status to the FRS improved risk prediction by the AUC (0.608, P = 0.02) and NRI (0.093, P = 0.008) in men, but not women (P ≥ 0.24). CONCLUSIONS: While none of these risk markers individually or in combination improved risk prediction among women, a combination of KIF6 719Arg carrier status and CRP levels modestly improved risk prediction among white men; although this improvement is not significant after multiple-testing correction. These observations should be investigated in other prospective studies.

Single variants can explain the association between coronary heart disease and haplotypes in the apolipoprotein(a) locus.

OBJECTIVE: LPA encodes apolipoprotein(a), and a CCTC haplotype in the LPA locus is associated with CHD. The 4399Met variant (rs3798220) of LPA has a risk estimate for CHD similar to that of the CCTC haplotype. We asked whether co-incidence with the 4399Met variant explained the association of the haplotype with CHD. METHODS: We stratified by the 4399Met variant and another LPA SNP (rs10455872) associated with CHD and tested the association between CHD and 4 SNPs that define two haplotypes associated with CHD: CCTC and CTTG. RESULTS: For CCTC, in the presence of the rs3798220 risk allele the OR was 1.68 (95% CI: 1.05-2.68, P=0.03) versus 0.30 (95% CI: 0.06-1.59, P=0.16) with the non-risk allele. For CTTG, in the presence of the rs10455872 risk allele the OR was 1.57 (95% CI: 1.15-2.13, P=0.004) versus 1.04 (95% CI: 0.79-1.35, P=0.77) with the non-risk allele. CONCLUSION: The rs3798220 and rs10455872 SNPs explain the association of the CCTC and CTTG haplotypes with CHD.

Effect of pravastatin therapy on coronary events in carriers of the KIF6 719Arg allele from the cholesterol and recurrent events trial.

A previous genetic analysis of the Cholesterol and Recurrent Events (CARE) trial found that carriers of the 719Arg allele of the kinesin family member 6 gene (KIF6) (rs20455), but not noncarriers, received significant event reduction from pravastatin therapy. However, that previous analysis of CARE included only Caucasian patients and was limited to the myocardial infarction components of the primary end point. Therefore, the aim of this study was to investigate whether pravastatin therapy reduced primary end point events in KIF6 719Arg carriers and noncarriers, separately, in the combined ethnic groups of CARE. The effect of pravastatin therapy on primary end point events (fatal coronary event or nonfatal myocardial infarction) was investigated in Cox regression models that adjusted for population structure using either self-reported ethnicity or the principal components of genetic heterogeneity. After adjustment for age, gender, and self-reported ethnicity, pravastatin therapy reduced events in carriers of KIF6 719Arg (hazard ratio [HR] 0.63, 95% confidence interval [CI] 0.49 to 0.83) but not in noncarriers (HR 1.01, 95% CI 0.69 to 1.45) (p for interaction = 0.049). After adjustment for age, gender, traditional risk factors, and principal components, pravastatin therapy reduced events in carriers of 719Arg (HR 0.64, 95% CI 0.49 to 0.85) but not in noncarriers (HR 0.90, 95% CI 0.62 to 1.32) (p for interaction = 0.14). In conclusion, in an analysis that included CARE patients of all ethnic groups, pravastatin therapy significantly and substantially reduced primary end point events in carriers of the KIF6 719Arg allele but not in noncarriers.

Polymorphism in the apolipoprotein(a) gene, plasma lipoprotein(a), cardiovascular disease, and low-dose aspirin therapy.

OBJECTIVE: A minor allele variant (rs3798220) of apolipoprotein(a) has been reported to be associated with elevated plasma lipoprotein(a) [Lp(a)] and increased cardiovascular risk. We investigated whether this allele was associated with elevated Lp(a) and cardiovascular risk in the Women's Health Study, a randomized trial of low-dose aspirin, and whether aspirin reduced cardiovascular risk in minor allele carriers. METHODS AND RESULTS: Genotypes of rs3798220 were determined for 25,131 initially healthy Caucasian participants. Median Lp(a) levels at baseline were 10.0, 79.5, and 153.9mg/dL for major allele homozygotes, heterozygotes, and minor allele homozygotes, respectively (P<0.0001). During the 9.9 years of follow-up, minor allele carriers (3.7%) in the placebo group had twofold higher risk of major cardiovascular events than non-carriers (age-adjusted hazard ratio (HR)=2.21, 95% CI: 1.39-3.52). Among carriers, risk was reduced more than twofold by aspirin: for aspirin compared with placebo the age-adjusted HR was 0.44 (95% CI: 0.20-0.94); risk was not significantly reduced among non-carriers (age-adjusted HR=0.91, 95% CI: 0.77-1.08). This interaction between carrier status and aspirin allocation was significant (P=0.048). CONCLUSIONS: In the Women's Health Study, carriers of an apolipoprotein(a) variant had elevated Lp(a), doubled cardiovascular risk, and appeared to benefit more from aspirin than non-carriers.

GOSR2 Lys67Arg is associated with hypertension in whites.

BACKGROUND: Hypertension is a risk factor for coronary heart disease (CHD), but the causes of hypertension remain largely unknown. Genetic variation is thought to contribute to the etiology of hypertension. We tested a single-nucleotide polymorphism (SNP) (Lys67Arg, rs197922) in the Golgi SNAP Receptor Complex Member 2 (GOSR2) gene for association with hypertension and blood pressure (BP). We chose this SNP because it was nominally associated with CHD in earlier studies. Further, GOSR2 is located in a linkage region for hypertension and BP in human and animal studies. METHODS: We used logistic and linear regression to test associations of the GOSR2 SNP with hypertension and BP among 3,528 blacks and 9,861 whites from the Atherosclerosis Risk in Communities (ARIC) study. Race-specific regression models of hypertension were adjusted for age and gender. Regression models of BP were further adjusted for antihypertensive medication use. RESULTS: The GOSR2 Lys67 allele was associated with hypertension in whites (odds ratio (OR) = 1.09, P = 0.01) but not blacks (OR = 0.96, P = 0.47). The Lys67 allele was associated with increased systolic BP (SBP) in both races (0.87 mm Hg, P < 0.001 among whites and 1.05 mm Hg, P = 0.05 among blacks). A similar association in whites was observed for the GOSR2 SNP and SBP in the Women's Genome Health Study (WGHS) (OR = 1.03, P = 0.04). The OR remained unchanged after adjustment for antihypertensive medication use (OR = 1.03, P = 0.11), though it was no longer statistically significant. CONCLUSIONS: We found evidence that a SNP in GOSR2 is modestly associated with hypertension in whites from the ARIC study and the WGHS.