Left ventricular (LV) hypertrophy, highest in prevalence among African Americans, is an established risk factor heart failure. Several genome wide association studies have identified common variants associated with LV-related quantitative-traits in African Americans. To date, however, the effect of rare variants on these traits has not been extensively studied, especially in minority groups. We therefore investigated the association between rare variants and LV traits among 1,934 African Americans using exome chip data from the Hypertension Genetic Epidemiology Network (HyperGEN) study, with replication in 1,090 African American from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. We used single-variant analyses and gene-based tests to investigate the association between 86,927 variants and six structural and functional LV traits including LV mass, LV internal dimension-diastole, relative wall thickness, left atrial dimension (LAD), fractional shortening (FS), and the ratio of LV early-to-late transmitral velocity (E/A ratio). Only rare variants (MAF <1% and <5%) were considered in gene-based analyses. In gene-based analyses, we found a statistically significant association between potassium voltage-gated channel subfamily H member 4 (KCNH4) and E/A ratio (P=8.7*10-8 using a burden test). Endonuclease G (ENDOG) was associated with LAD using the Madsen Browning weighted burden (MB) test (P=1.4*10-7). Neither gene result was replicated in GENOA, but the direction of effect of single variants in common was comparable. G protein-coupled receptor 55 (GPR55) was marginally associated with LAD in HyperGEN (P=3.2*10-5 using the MB test) and E/A ratio in GENOA, but with opposing directions of association for variants in common (P=0.03 for the MB test). No single variant was statistically significantly associated with any trait after correcting for multiple testing. The findings in this study highlight the potential cumulative contributions of rare variants to LV traits which, if validated, could improve our understanding of heart failure in African Americans.
Background: In the United States, young adults (18-39 year-olds) have the lowest hypertension control rates (35%) compared to middle-aged (58%) and older (54%) adults. Ambulatory care for hypertension management often focuses on medication with little time for self-management and behavioral counseling. This study was designed to evaluate the feasibility of MyHEART, a telephone-based health coach self-management intervention for young adults. The goals were to determine the intervention's ability to: 1) recruit young adults with uncontrolled hypertension, 2) maintain ongoing communication between the coach and participants, 3) increase participants' engagement in self-management, 4) document coach-patient communication in the electronic health record, and 5) assess patient acceptability.
Methods: Eligible participants were identified through the electronic health record. Inclusion criteria included 18-39 year-olds, with ICD-9 hypertension diagnoses and uncontrolled hypertension (≥ 140/90 mmHg), receiving regular primary care at a large multispecialty group practice. The intervention consisted of 6 telephone self-management sessions by a health coach targeting lifestyle modifications. Patients completed an open-ended acceptability survey.
Results: Study uptake was 47% (9 enrolled/19 eligible). Mean (SD) age was 35.8 (2.6) years, 78% male, and 33% Black. Over 85% of enrolled young adults maintained communication with their health coach. At baseline, 11% reported checking their blood pressure outside of clinic; 44% reported blood pressure monitoring after the study. All coach-patient encounters were successfully documented in the electronic health record for primary care provider review. Open-ended responses from all surveys indicated that participants had a positive experience with the MyHEART intervention.
Conclusions: This study demonstrated that MyHEART was feasible and acceptable to young adults with uncontrolled hypertension. Health coaches can effectively maintain ongoing communication with young adults, document communication in the electronic health record, and increase engagement with home blood pressure monitoring. The results of this study will inform a multi-center young adult randomized controlled trial of MyHEART.