Rare coding variants in RCN3 are associated with blood pressure.

BACKGROUND: While large genome-wide association studies have identified nearly one thousand loci associated with variation in blood pressure, rare variant identification is still a challenge. In family-based cohorts, genome-wide linkage scans have been successful in identifying rare genetic variants for blood pressure. This study aims to identify low frequency and rare genetic variants within previously reported linkage regions on chromosomes 1 and 19 in African American families from the Trans-Omics for Precision Medicine (TOPMed) program. Genetic association analyses weighted by linkage evidence were completed with whole genome sequencing data within and across TOPMed ancestral groups consisting of 60,388 individuals of European, African, East Asian, Hispanic, and Samoan ancestries. RESULTS: Associations of low frequency and rare variants in RCN3 and multiple other genes were observed for blood pressure traits in TOPMed samples. The association of low frequency and rare coding variants in RCN3 was further replicated in UK Biobank samples (N = 403,522), and reached genome-wide significance for diastolic blood pressure (p = 2.01 × 10- 7). CONCLUSIONS: Low frequency and rare variants in RCN3 contributes blood pressure variation. This study demonstrates that focusing association analyses in linkage regions greatly reduces multiple-testing burden and improves power to identify novel rare variants associated with blood pressure traits.

Factors associated with antihypertensive monotherapy among US adults with treated hypertension and uncontrolled blood pressure overall and by race/ethnicity, National Health and Nutrition Examination Survey 2013-2018.

BACKGROUND: Treating hypertension with antihypertensive medications combinations, rather than one medication (ie, monotherapy), is underused in the United States, particularly in certain race/ethnic groups. Identifying factors associated with monotherapy use despite uncontrolled blood pressure (BP) overall and within race/ethnic groups may elucidate intervention targets in under-treated populations. METHODS: Cross-sectional analysis of National Health and Nutrition Examination Surveys (NHANES; 2013-2014 through 2017-2018). We included participants age ≥20 years with hypertension, taking at least one antihypertensive medication, and uncontrolled BP (systolic BP [SBP] ≥ 140 mmHg or diastolic BP [DBP] ≥ 90 mmHg). Demographic, clinical, and healthcare-access factors associated with antihypertensive monotherapy were determined using multivariable-adjusted Poisson regression. RESULTS: Among 1,597 participants with hypertension and uncontrolled BP, age- and sex- adjusted prevalence of monotherapy was 42.6% overall, 45.4% among non-Hispanic White, 31.9% among non-Hispanic Black, 39.6% among Hispanic, and 50.9% among non-Hispanic Asian adults. Overall, higher SBP was associated with higher monotherapy use, while older age, having a healthcare visit in the previous year, higher body mass index, and having heart failure were associated with lower monotherapy use. CONCLUSION: Clinical and healthcare-access factors, including a healthcare visit within the previous year and co-morbid conditions were associated with a higher likelihood of combination antihypertensive therapy.

Estimating the optimal individualized treatment rule from a cost-effectiveness perspective.

Optimal individualized treatment rules (ITRs) provide customized treatment recommendations based on subject characteristics to maximize clinical benefit in accordance with the objectives in precision medicine. As a result, there is growing interest in developing statistical tools for estimating optimal ITRs in evidence-based research. In health economic perspectives, policy makers consider the tradeoff between health gains and incremental costs of interventions to set priorities and allocate resources. However, most work on ITRs has focused on maximizing the effectiveness of treatment without considering costs. In this paper, we jointly consider the impact of effectiveness and cost on treatment decisions and define ITRs under a composite-outcome setting, so that we identify the most cost-effective ITR that accounts for individual-level heterogeneity through direct optimization. In particular, we propose a decision-tree-based statistical learning algorithm that uses a net-monetary-benefit-based reward to provide nonparametric estimations of the optimal ITR. We provide several approaches to estimating the reward underlying the ITR as a function of subject characteristics. We present the strengths and weaknesses of each approach and provide practical guidelines by comparing their performance in simulation studies. We illustrate the top-performing approach from our simulations by evaluating the projected 15-year personalized cost-effectiveness of the intensive blood pressure control of the Systolic Blood Pressure Intervention Trial (SPRINT) study.

Potential Cardiovascular Disease Events Prevented with Adoption of the 2017 American College of Cardiology/American Heart Association Blood Pressure Guideline.

BACKGROUND: Over 10 years, achieving and maintaining 2017 ACC/AHA guideline goals could prevent 3.0 million (UR, 1.1-5.1 million), 0.5 million (UR, 0.2-0.7 million), and 1.4 million (UR, 0.6-2.0 million) cardiovascular disease (CVD) events compared with maintaining current blood pressure (BP) levels, achieving 2003 Seventh Joint National Committee Report goals, and achieving 2014 Eighth Joint National Committee goals, respectively. We estimated the number of cardiovascular disease events prevented and treatment-related serious adverse events incurred over 10 years among US adults with hypertension by achieving 2017 ACC/AHA guideline-recommended BP goals compared with (1) current BP levels, (2) achieving 2003 Seventh Joint National Committee Report BP goals, and (3) achieving 2014 Eighth Joint National Committee panel member report BP goals. METHODS: US adults aged ≥45 years with an indication for BP treatment were grouped according to recommendations for antihypertensive drug therapy in the 2017 ACC/AHA guideline, 2003 Seventh Joint National Committee Report, and 2014 Eighth Joint National Committee. Population sizes were estimated from the 2011 to 2014 National Health and Nutrition Examination Surveys. Rates for fatal and nonfatal CVD events (stroke, coronary heart disease, or heart failure) were estimated from the REGARDS (REasons for Geographic And Racial Differences in Stroke) study, weighted to the US population. CVD risk reductions with treatment to BP goals and risk for serious adverse events were obtained from meta-analyses of BP-lowering trials. CVD events prevented and treatment-related nonfatal serious adverse events over 10 years were calculated. Uncertainty surrounding main data inputs was expressed in uncertainty ranges (UR). RESULTS: Over ten years, achieving and maintaining 2017 ACC/AHA guideline goals compared with current BP levels, achieving 2003 Seventh Joint National Committee Report goals, or achieving 2014 Eighth Joint National Committee goals could prevent 3.0 million (UR, 1.1-5.1 million), 0.5 million (UR, 0.2-0.7 million), or 1.4 million (UR, 0.6-2.0 million) CVD events, respectively. Compared with current BP levels, achieving and maintaining 2017 goals could prevent 71.9 (UR, 26.6-122.3) CVD events per 1000 treated. Achieving 2017 guideline BP goals compared with current BP levels could also lead to nearly 3.3 million more serious adverse events over 10 years (UR, 2.2-4.4 million). CONCLUSIONS: Achieving and maintaining 2017 ACC/AHA BP goals could prevent a greater number of CVD events than achieving 2003 Seventh Joint National Committee Report or 2014 Eighth Joint National Committee BP goals but could also lead to more serious adverse events.

Cost-Effectiveness of Intensive versus Standard Blood-Pressure Control.

BACKGROUND: In the Systolic Blood Pressure Intervention Trial (SPRINT), adults at high risk for cardiovascular disease who received intensive systolic blood-pressure control (target, <120 mm Hg) had significantly lower rates of death and cardiovascular disease events than did those who received standard control (target, <140 mm Hg). On the basis of these data, we wanted to determine the lifetime health benefits and health care costs associated with intensive control versus standard control. METHODS: We used a microsimulation model to apply SPRINT treatment effects and health care costs from national sources to a hypothetical cohort of SPRINT-eligible adults. The model projected lifetime costs of treatment and monitoring in patients with hypertension, cardiovascular disease events and subsequent treatment costs, treatment-related risks of serious adverse events and subsequent costs, and quality-adjusted life-years (QALYs) for intensive control versus standard control of systolic blood pressure. RESULTS: We determined that the mean number of QALYs would be 0.27 higher among patients who received intensive control than among those who received standard control and would cost approximately $47,000 more per QALY gained if there were a reduction in adherence and treatment effects after 5 years; the cost would be approximately $28,000 more per QALY gained if the treatment effects persisted for the remaining lifetime of the patient. Most simulation results indicated that intensive treatment would be cost-effective (51 to 79% below the willingness-to-pay threshold of $50,000 per QALY and 76 to 93% below the threshold of $100,000 per QALY), regardless of whether treatment effects were reduced after 5 years or persisted for the remaining lifetime. CONCLUSIONS: In this simulation study, intensive systolic blood-pressure control prevented cardiovascular disease events and prolonged life and did so at levels below common willingness-to-pay thresholds per QALY, regardless of whether benefits were reduced after 5 years or persisted for the patient's remaining lifetime. (Funded by the National Heart, Lung, and Blood Institute and others; SPRINT ClinicalTrials.gov number, NCT01206062 .).

Relationship Between ACE2 and Other Components of the Renin-Angiotensin System.

PURPOSE OF THE REVIEW: Angiotensin-converting enzyme 2 (ACE2) is a key counter-regulatory component of the renin-angiotensin system. Here, we briefly review the mechanistic and target organ effects related to ACE2 activity, and the importance of ACE2 in SARS-CoV-2 infection. RECENT FINDINGS: ACE2 converts angiotensin (Ang) II to Ang-(1-7), which directly opposes the vasoconstrictive, proinflammatory, and prothrombotic effects of Ang II. ACE2 also facilitates SARS-CoV-2 viral entry into host cells. Drugs that interact with the renin-angiotensin system may impact ACE2 expression and COVID-19 pathogenesis; however, the magnitude and direction of these effects are unknown at this time. High quality research is needed to improve our understanding of how agents that act on the renin-angiotensin system impact ACE2 and COVID-19-related disease outcomes.

Fixed-Dose Combination Medications for Treating Hypertension: A Review of Effectiveness, Safety, and Challenges.

PURPOSE OF REVIEW: To summarize the recent evidence on the effectiveness and safety of antihypertensive fixed-dose combination (FDC) medications, and to describe the facilitators and barriers to implementing FDCs in US clinical practice. RECENT FINDINGS: Recent clinical practice guidelines include FDC use for treating high BP. Clinical trials in recent years support the use of antihypertensive FDCs including low-dose triple- and quadruple-therapy FDCs. Initiating a low-to-standard dose dual-therapy FDCs showed better BP control than initiating treatment with a standard-dose monotherapy, and triple-therapy FDCs produced better BP control rates than dual-therapy FDCs. Retrospective cohort studies showed that FDCs are associated with increased medication adherence, reduced clinical inertia, decreased time to BP control, and improved cardiovascular outcomes. We further discussed barriers and facilitators of wider implementation of antihypertensive FDCs in clinical practice. FDC treatment for hypertension is not commonly used despite historical and recent data which support the effectiveness, safety, and benefits of FDCs. Simplified and protocolized treatment algorithms, team-based care, shared decision-making principles are crucial to successful utilization and implementation of FDC in clinical practice.

Leveraging linkage evidence to identify low-frequency and rare variants on 16p13 associated with blood pressure using TOPMed whole genome sequencing data.

In this study, we investigated low-frequency and rare variants associated with blood pressure (BP) by focusing on a linkage region on chromosome 16p13. We used whole genome sequencing (WGS) data obtained through the NHLBI Trans-Omics for Precision Medicine (TOPMed) program on 395 Cleveland Family Study (CFS) European Americans (CFS-EA). By analyzing functional coding variants and non-coding rare variants with CADD score > 10 residing within the chromosomal region in families with linkage evidence, we observed 25 genes with nominal statistical evidence (burden or SKAT p < 0.05). One of the genes is RBFOX1, an evolutionarily conserved RNA-binding protein that regulates tissue-specific alternative splicing that we previously reported to be associated with BP using exome array data in CFS. After follow-up analysis of the 25 genes in ten independent TOPMed studies with individuals of European, African, and East Asian ancestry, and Hispanics (N = 29,988), we identified variants in SLX4 (p = 2.19 × 10-4) to be significantly associated with BP traits when accounting for multiple testing. We also replicated the associations previously reported for RBFOX1 (p = 0.007). Follow-up analysis with GTEx eQTL data shows SLX4 variants are associated with gene expression in coronary artery, multiple brain tissues, and right atrial appendage of the heart. Our study demonstrates that linkage analysis of family data can provide an efficient approach for detecting rare variants associated with complex traits in WGS data.

Cost-Effectiveness and Challenges of Implementing Intensive Blood Pressure Goals and Team-Based Care.

PURPOSE OF REVIEW: Review the effectiveness, cost-effectiveness, and implementation challenges of intensive blood pressure (BP) control and team-based care initiatives. RECENT FINDINGS: Intensive BP control is an effective and cost-effective intervention; yet, implementation in routine clinical practice is challenging. Several models of team-based care for hypertension management have been shown to be more effective than usual care to control BP. Additional research is needed to determine the cost-effectiveness of team-based care models relative to one another and as they relate to implementing intensive BP goals. As a focus of healthcare shifts to value (i.e., cost, effectiveness, and patient preferences), formal cost-effectiveness analyses will inform which team-based initiatives hold the highest value in different healthcare settings with different populations and needs. Several challenges, including clinical inertia, financial investment, and billing restrictions for pharmacist-delivered services, will need to be addressed in order to improve public health through intensive BP control and team-based care.

Potential Deaths Averted and Serious Adverse Events Incurred From Adoption of the SPRINT (Systolic Blood Pressure Intervention Trial) Intensive Blood Pressure Regimen in the United States: Projections From NHANES (National Health and Nutrition Examination Survey).

BACKGROUND: SPRINT (Systolic Blood Pressure Intervention Trial) demonstrated a 27% reduction in all-cause mortality with a systolic blood pressure (SBP) goal of <120 versus <140 mm Hg among US adults at high cardiovascular disease risk but without diabetes mellitus, stroke, or heart failure. To quantify the potential benefits and risks of SPRINT intensive goal implementation, we estimated the deaths prevented and excess serious adverse events incurred if the SPRINT intensive SBP treatment goal were implemented in all eligible US adults. METHODS: SPRINT eligibility criteria were applied to the 1999 to 2006 National Health and Nutrition Examination Survey and linked with the National Death Index through December 2011. SPRINT eligibility included age ≥50 years, SBP of 130 to 180 mm Hg (depending on the number of antihypertensive medications being taken), and high cardiovascular disease risk. Exclusion criteria were diabetes mellitus, history of stroke, >1 g proteinuria, heart failure, estimated glomerular filtration rate <20 mL·min-1·1.73 m-2, or dialysis. Annual mortality rates were calculated by dividing the Kaplan-Meier 5-year mortality by 5. Hazard ratios for all-cause mortality and heart failure and absolute risks for serious adverse events in SPRINT were used to estimate the number of potential deaths and heart failure cases prevented and serious adverse events incurred with intensive SBP treatment. RESULTS: The mean age was 68.6 years, and 83.2% and 7.4% were non-Hispanic white and non-Hispanic black, respectively. The annual mortality rate was 2.20% (95% confidence interval [CI], 1.91-2.48), and intensive SBP treatment was projected to prevent ≈107 500 deaths per year (95% CI, 93 300-121 200) and give rise to 56 100 (95% CI, 50 800-61 400) episodes of hypotension, 34 400 (95% CI, 31 200-37 600) episodes of syncope, 43 400 (95% CI, 39 400-47 500) serious electrolyte disorders, and 88 700 (95% CI, 80 400-97 000) cases of acute kidney injury per year. The analysis-of-extremes approach indicated that the range of estimated lower- and upper-bound number of deaths prevented per year with intensive SBP control was 34 600 to 179 600. Intensive SBP control was projected to prevent 46 100 (95% CI, 41 800-50 400) cases of heart failure annually. CONCLUSIONS: If fully implemented in eligible US adults, intensive SBP treatment could prevent ≈107 500 deaths per year. A consequence of this treatment strategy, however, could be an increase in serious adverse events.

Thresholds for Ambulatory Blood Pressure Among African Americans in the Jackson Heart Study.

BACKGROUND: Ambulatory blood pressure (BP) monitoring is the reference standard for out-of-clinic BP measurement. Thresholds for identifying ambulatory hypertension (daytime systolic BP [SBP]/diastolic BP [DBP] ≥135/85 mm Hg, 24-hour SBP/DBP ≥130/80 mm Hg, and nighttime SBP/DBP ≥120/70 mm Hg) have been derived from European, Asian, and South American populations. We determined BP thresholds for ambulatory hypertension in a US population-based sample of African American adults. METHODS: We analyzed data from the Jackson Heart Study, a population-based cohort study comprised exclusively of African American adults (n=5306). Analyses were restricted to 1016 participants who completed ambulatory BP monitoring at baseline in 2000 to 2004. Mean SBP and DBP levels were calculated for daytime (10:00 am-8:00 pm), 24-hour (all available readings), and nighttime (midnight-6:00 am) periods, separately. Daytime, 24-hour, and nighttime BP thresholds for ambulatory hypertension were identified using regression- and outcome-derived approaches. The composite of a cardiovascular disease or an all-cause mortality event was used in the outcome-derived approach. For this latter approach, BP thresholds were identified only for SBP because clinic DBP was not associated with the outcome. Analyses were stratified by antihypertensive medication use. RESULTS: Among participants not taking antihypertensive medication, the regression-derived thresholds for daytime, 24-hour, and nighttime SBP/DBP corresponding to clinic SBP/DBP of 140/90 mm Hg were 134/85 mm Hg, 130/81 mm Hg, and 123/73 mm Hg, respectively. The outcome-derived thresholds for daytime, 24-hour, and nighttime SBP corresponding to a clinic SBP ≥140 mm Hg were 138 mm Hg, 134 mm Hg, and 129 mm Hg, respectively. Among participants taking antihypertensive medication, the regression-derived thresholds for daytime, 24-hour, and nighttime SBP/DBP corresponding to clinic SBP/DBP of 140/90 mm Hg were 135/85 mm Hg, 133/82 mm Hg, and 128/76 mm Hg, respectively. The corresponding outcome-derived thresholds for daytime, 24-hour, and nighttime SBP were 140 mm Hg, 137 mm Hg, and 133 mm Hg, respectively, among those taking antihypertensive medication. CONCLUSIONS: On the basis of the outcome-derived approach for SBP and regression-derived approach for DBP, the following definitions for daytime, 24-hour, and nighttime hypertension corresponding to clinic SBP/DBP ≥140/90 mm Hg are proposed for African American adults: daytime SBP/DBP ≥140/85 mm Hg, 24-hour SBP/DBP ≥135/80 mm Hg, and nighttime SBP/DBP ≥130/75 mm Hg, respectively.

A new modeling and inference approach for the Systolic Blood Pressure Intervention Trial outcomes.

Background/aims In clinical trials with time-to-event outcomes, usually the significance tests and confidence intervals are based on a proportional hazards model. Thus, the temporal pattern of the treatment effect is not directly considered. This could be problematic if the proportional hazards assumption is violated, as such violation could impact both interim and final estimates of the treatment effect. Methods We describe the application of inference procedures developed recently in the literature for time-to-event outcomes when the treatment effect may or may not be time-dependent. The inference procedures are based on a new model which contains the proportional hazards model as a sub-model. The temporal pattern of the treatment effect can then be expressed and displayed. The average hazard ratio is used as the summary measure of the treatment effect. The test of the null hypothesis uses adaptive weights that often lead to improvement in power over the log-rank test. Results Without needing to assume proportional hazards, the new approach yields results consistent with previously published findings in the Systolic Blood Pressure Intervention Trial. It provides a visual display of the time course of the treatment effect. At four of the five scheduled interim looks, the new approach yields smaller p values than the log-rank test. The average hazard ratio and its confidence interval indicates a treatment effect nearly a year earlier than a restricted mean survival time-based approach. Conclusion When the hazards are proportional between the comparison groups, the new methods yield results very close to the traditional approaches. When the proportional hazards assumption is violated, the new methods continue to be applicable and can potentially be more sensitive to departure from the null hypothesis.

Association of Blood Pressure Classification in Young Adults Using the 2017 American College of Cardiology/American Heart Association Blood Pressure Guideline With Cardiovascular Events Later in Life.

Importance: Little is known regarding the association between level of blood pressure (BP) in young adulthood and cardiovascular disease (CVD) events by middle age. Objective: To assess whether young adults who developed hypertension, defined by the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) BP guideline, before age 40 years have higher risk for CVD events compared with those who maintained normal BP. Design, Setting, and Participants: Analyses were conducted in the prospective cohort Coronary Artery Risk Development in Young Adults (CARDIA) study, started in March 1985. CARDIA enrolled 5115 African American and white participants aged 18 to 30 years from 4 US field centers (Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California). Outcomes were available through August 2015. Exposures: Using the highest BP measured from the first examination to the examination closest to, but not after, age 40 years, each participant was categorized as having normal BP (untreated systolic BP [SBP] <120 mm Hg and diastolic BP [DBP] <80 mm Hg; n = 2574); elevated BP (untreated SBP 120-129 mm Hg and DBP <80 mm Hg; n = 445); stage 1 hypertension (untreated SBP 130-139 mm Hg or DBP 80-89 mm Hg; n = 1194); or stage 2 hypertension (SBP ≥140 mm Hg, DBP ≥90 mm Hg, or taking antihypertensive medication; n = 638). Main Outcomes and Measures: CVD events: fatal and nonfatal coronary heart disease (CHD), heart failure, stroke, transient ischemic attack, or intervention for peripheral artery disease (PAD). Results: The final cohort included 4851 adults (mean age when follow-up for outcomes began, 35.7 years [SD, 3.6]; 2657 women [55%]; 2441 African American [50%]; 206 taking antihypertensive medication [4%]). Over a median follow-up of 18.8 years, 228 incident CVD events occurred (CHD, 109; stroke, 63; heart failure, 48; PAD, 8). CVD incidence rates for normal BP, elevated BP, stage 1 hypertension, and stage 2 hypertension were 1.37 (95% CI, 1.07-1.75), 2.74 (95% CI, 1.78-4.20), 3.15 (95% CI, 2.47-4.02), and 8.04 (95% CI, 6.45-10.03) per 1000 person-years, respectively. After multivariable adjustment, hazard ratios for CVD events for elevated BP, stage 1 hypertension, and stage 2 hypertension vs normal BP were 1.67 (95% CI, 1.01-2.77), 1.75 (95% CI, 1.22-2.53), and 3.49 (95% CI, 2.42-5.05), respectively. Conclusions and Relevance: Among young adults, those with elevated blood pressure, stage 1 hypertension, and stage 2 hypertension before age 40 years, as defined by the blood pressure classification in the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines, had significantly higher risk for subsequent cardiovascular disease events compared with those with normal blood pressure before age 40 years. The ACC/AHA blood pressure classification system may help identify young adults at higher risk for cardiovascular disease events.

Circulating Procollagen Type III N-Terminal Peptide and Mortality Risk in African Americans With Heart Failure.

BACKGROUND: Procollagen type III N-terminal peptide (PIIINP) is a biomarker of cardiac fibrosis that is associated with heart failure prognosis in whites. Its prognostic significance in African Americans is unknown. We sought to determine whether PIIINP is associated with outcomes in African Americans with heart failure. METHODS AND RESULTS: Blood was collected from 138 African Americans with heart failure for determining PIIINP and genetic ancestry, and patients were followed prospectively for death or hospitalization for heart failure. PIIINP was inversely correlated with West African ancestry (R(2) = 0.061; P = .010). PIIINP > 4.88 ng/mL was associated with all-cause mortality on univariate (hazard ratio [HR] 4.9, 95% confidence interval [CI] 2.2-11.0; P < .001) and multivariate (HR 5.8; 95% CI 1.9-17.3; P = .002) analyses over a median follow-up period of 3 years. We also observed an increased risk for the combined outcome of all-cause mortality or hospitalization for heart failure with PIIINP > 4.88 ng/mL on univariate (HR 2.6, 95% CI 1.6-5.0; P < .001) and multivariate (HR 2.4, 95% CI 1.2-4.7; P = .016) analyses. CONCLUSIONS: High circulating PIIINP is associated with poor outcomes in African Americans with chronic heart failure, suggesting that PIIINP may be useful in identifying African Americans who may benefit from additional therapy to combat fibrosis as a means of improving prognosis.

Upper-Extremity Deep-Vein Thrombosis: A Retrospective Cohort Evaluation of Thrombotic Risk Factors at a University Teaching Hospital Antithrombosis Clinic.

BACKGROUND: Upper-extremity deep-vein thrombosis (UEDVT) causes significant morbidity and mortality and is not well characterized in the existing literature, particularly in underrepresented minorities such as African Americans. OBJECTIVE: To describe the characteristics of a cohort of patients with UEDVT seen at an urban academic medical center. METHODS: This was a retrospective cohort study among patients with a confirmed UEDVT at the University of Illinois Hospital and Health Sciences System between 1996 and 2011. Patients were identified by ICD-9 code for UEDVT. Variables collected include thrombotic risk factors and outcomes, including recurrent thrombosis and bleeding. RESULTS: We identified 229 patients with UEDVT; 71% were African American, and 11% were diagnosed with sickle cell disease. The average number of UEDVT risk factors was 4.40 ± 1.5, the most common being central venous catheter (CVC) use (178, 78%). In the year following UEDVT, 13% experienced recurrent thrombosis, and 6% experienced major bleeding. Of 181 patients receiving warfarin after an UEDVT, 36% of international normalized ratio (INR) values were therapeutic. Patients with sickle cell disease had a lower proportion of INRs within the target range (25% vs 38%, P < 0.01), and were more likely to be lost to follow-up (67% vs 46%, P = 0.05) and experience a recurrent thrombotic event (29% vs 11%, P = 0.02). CONCLUSION: A CVC is the most common risk factor for UEDVT; however, patients with sickle cell disease demonstrate additional unique demographics and risk factors. Patients included in this underrepresented demographic cohort had a low quality of anticoagulation control, particularly those with sickle cell disease.

Poor warfarin dose prediction with pharmacogenetic algorithms that exclude genotypes important for African Americans.

OBJECTIVES: Recent clinical trial data cast doubt on the utility of genotype-guided warfarin dosing, specifically showing worse dosing with a pharmacogenetic versus clinical dosing algorithm in African Americans. However, many genotypes important in African Americans were not accounted for. We aimed to determine whether omission of the CYP2C9*5, CYP2C9*6, CYP2C9*8, CYP2C9*11 alleles and rs12777823 G > A genotype affects performance of dosing algorithms in African Americans. METHODS: In a cohort of 274 warfarin-treated African Americans, we examined the association between the CYP2C9*5, CYP2C9*6, CYP2C9*8, CYP2C9*11 alleles and rs12777823 G > A genotype and warfarin dose prediction error with pharmacogenetic algorithms used in clinical trials. RESULTS: The http://www.warfarindosing.org algorithm overestimated doses by a median (interquartile range) of 1.2 (0.02-2.6) mg/day in rs12777823 heterozygotes (P<0.001 for predicted vs. observed dose), 2.0 (0.6-2.8) mg/day in rs12777823 variant homozygotes (P = 0.004), and 2.2 (0.5-2.9) mg/day in carriers of a CYP2C9 variant (P < 0.001). The International Warfarin Pharmacogenetics Consortium (IWPC) algorithm underdosed warfarin by 0.8 (-2.3 to 0.4) mg/day for patients with the rs12777823 GG genotype (P < 0.001) and overdosed warfarin by 0.7 (-0.4 to 1.9) mg/day in carriers of a variant CYP2C9 allele (P = 0.04). Modifying the http://www.warfarindosing.org algorithm to adjust for variants important in African Americans led to better dose prediction than either the original http://www.warfarindosing.org (P < 0.01) or IWPC (P < 0.01) algorithm. CONCLUSION: These data suggest that, when providing genotype-guided warfarin dosing, failure to account for variants important in African Americans leads to significant dosing error in this population.