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This article describes the October 2020 proceedings of the Million Hearts Cardiac Rehabilitation Think Tank: Accelerating New Care Models, convened with representatives from professional organizations, cardiac rehabilitation (CR) programs, academic institutions, federal agencies, payers, and patient representative groups. As CR delivery evolves, terminology is evolving to reflect not where activities occur (eg, center, home) but how CR is delivered: in-person synchronous, synchronous with real-time audiovisual communication (virtual), or asynchronous (remote). Patients and CR staff may interact through ≥1 delivery modes. Though new models may change how CR is delivered and who can access CR, new models should not change what is delivered-a multidisciplinary program addressing CR core components. During the coronavirus disease 2019 (COVID-19) public health emergency, Medicare issued waivers to allow virtual CR; it is unclear whether these waivers will become permanent policy post-public health emergency. Given CR underuse and disparities in delivery, new models must equitably address patient and health system contributors to disparities. Strategies for implementing new CR care models address safety, exercise prescription, monitoring, and education. The available evidence supports the efficacy and safety of new CR care models. Still, additional research should study diverse populations, impact on patient-centered outcomes, effect on long-term outcomes and health care utilization, and implementation in diverse settings. CR is evolving to include in-person synchronous, virtual, and remote modes of delivery; there is significant enthusiasm for implementing new care models and learning how new care models can broaden access to CR, improve patient outcomes, and address health inequities.

The pharmacologic inhibition of proprotein convertase subtilisin-kexin type 9 (PCSK9) lowers lipoprotein (a) [Lp(a)] concentrations. However, the impact of genetic PCSK9 loss-of-function variants (LOFVs) on Lp(a) is uncertain. We determined the association of PCSK9 LOFVs with Lp(a) measures among black adults. Genotyping for PCSK9 LOFVs was conducted in 10,196 black Reasons for Geographic and Racial Differences in Stroke study participants. Among 241 participants with and 723 randomly selected participants without PCSK9 LOFVs, Lp(a) concentations, apo(a) kringle IV (KIV) repeats (a proxy for isoform size), and oxidized phospholipid (OxPL) apoB levels were measured using validated methods. Median Lp(a) concentrations among participants with and without PCSK9 LOFVs were 63.2 and 80.4 nmol/l, respectively (P = 0.016). After adjusting for age, sex, estimated glomerular filtration rate, LDL cholesterol, and statin use, participants with versus without a PCSK9 LOFV had a lower median Lp(a) concentration [Δ = -18.8 nmol/l (95% CI: -34.2, -3.3)]. Median apo(a) isoform sizes were 24 and 23 KIV repeats (P = 0.12) among participants with and without PCSK9 LOFVs, respectively [Δ = 1.1 (95% CI: 0.2, 2.0) after adjustment]. Median OxPL-apoB levels among participants with and without PCSK9 LOFVs were 3.4 and 4.1 nM (P = 0.20), respectively [Δ = -1.2 nM (95% CI -2.4, -0.04) after adjustment]. Among black adults, PCSK9 LOFVs were associated with lower Lp(a) concentration and OxPL-apoB levels.

Cardiac rehabilitation (CR) is an evidence-based intervention that uses patient education, health behavior modification, and exercise training to improve secondary prevention outcomes in patients with cardiovascular disease. CR programs reduce morbidity and mortality rates in adults with ischemic heart disease, heart failure, or cardiac surgery but are significantly underused, with only a minority of eligible patients participating in CR in the United States. New delivery strategies are urgently needed to improve participation. One potential strategy is home-based CR (HBCR). In contrast to center-based CR services, which are provided in a medically supervised facility, HBCR relies on remote coaching with indirect exercise supervision and is provided mostly or entirely outside of the traditional center-based setting. Although HBCR has been successfully deployed in the United Kingdom, Canada, and other countries, most US healthcare organizations have little to no experience with such programs. The purpose of this scientific statement is to identify the core components, efficacy, strengths, limitations, evidence gaps, and research necessary to guide the future delivery of HBCR in the United States. Previous randomized trials have generated low- to moderate-strength evidence that HBCR and center-based CR can achieve similar improvements in 3- to 12-month clinical outcomes. Although HBCR appears to hold promise in expanding the use of CR to eligible patients, additional research and demonstration projects are needed to clarify, strengthen, and extend the HBCR evidence base for key subgroups, including older adults, women, underrepresented minority groups, and other higher-risk and understudied groups. In the interim, we conclude that HBCR may be a reasonable option for selected clinically stable low- to moderate-risk patients who are eligible for CR but cannot attend a traditional center-based CR program.

Cardiac rehabilitation (CR) is an evidence-based intervention that uses patient education, health behavior modification, and exercise training to improve secondary prevention outcomes in patients with cardiovascular disease. CR programs reduce morbidity and mortality rates in adults with ischemic heart disease, heart failure, or cardiac surgery but are significantly underused, with only a minority of eligible patients participating in CR in the United States. New delivery strategies are urgently needed to improve participation. One potential strategy is home-based CR (HBCR). In contrast to center-based CR services, which are provided in a medically supervised facility, HBCR relies on remote coaching with indirect exercise supervision and is provided mostly or entirely outside of the traditional center-based setting. Although HBCR has been successfully deployed in the United Kingdom, Canada, and other countries, most US healthcare organizations have little to no experience with such programs. The purpose of this scientific statement is to identify the core components, efficacy, strengths, limitations, evidence gaps, and research necessary to guide the future delivery of HBCR in the United States. Previous randomized trials have generated low- to moderate-strength evidence that HBCR and center-based CR can achieve similar improvements in 3- to 12-month clinical outcomes. Although HBCR appears to hold promise in expanding the use of CR to eligible patients, additional research and demonstration projects are needed to clarify, strengthen, and extend the HBCR evidence base for key subgroups, including older adults, women, underrepresented minority groups, and other higher-risk and understudied groups. In the interim, we conclude that HBCR may be a reasonable option for selected clinically stable low- to moderate-risk patients who are eligible for CR but cannot attend a traditional center-based CR program.

BackgroundPrior studies have consistently demonstrated that blacks have an approximate 2-fold higher incidence of sudden cardiac death (SCD) than whites; however, these analyses have lacked individual-level sociodemographic, medical comorbidity, and behavioral health data.ObjectivesThe purpose of this study was to evaluate whether racial differences in SCD incidence are attributable to differences in the prevalence of risk factors or rather to underlying susceptibility to fatal arrhythmias.MethodsThe Reasons for Geographic and Racial Differences in Stroke study is a prospective, population-based cohort of adults from across the United States. Associations between race and SCD defined per National Heart, Lung, and Blood Institute criteria were assessed.ResultsAmong 22,507 participants (9,416 blacks and 13,091 whites) without a history of clinical cardiovascular disease, there were 174 SCD events (67 whites and 107 blacks) over a median follow-up of 6.1 years (interquartile range: 4.6 to 7.3 years). The age-adjusted SCD incidence rate (per 1,000 person-years) was higher in blacks (1.8; 95% confidence interval [CI]: 1.4 to 2.2) compared with whites (0.7; 95% CI: 0.6 to 0.9), with an unadjusted hazard ratio of 2.35; 95% CI: 1.74 to 3.20. The association of black race with SCD risk remained significant after adjustment for sociodemographics, comorbidities, behavioral measures of health, intervening cardiovascular events, and competing risks of non-SCD mortality (hazard ratio: 1.97; 95% CI: 1.39 to 2.77).ConclusionsIn a large biracial population of adults without a history of cardiovascular disease, SCD rates were significantly higher in blacks as compared with whites. These racial differences were not fully explained by demographics, adverse socioeconomic measures, cardiovascular risk factors, and behavioral measures of health.

BackgroundModerate-to-severe kidney disease increases risk for sudden cardiac death (SCD). Limited studies have evaluated how mild degrees of kidney dysfunction impact SCD risk.ObjectiveThe purpose of this study was to evaluate the association of albuminuria, which is one of the earliest biomarkers of kidney injury, and SCD.MethodsThe Reasons for Geographic and Racial Differences in Stroke (REGARDS) study is a prospective, population-based cohort of U.S. adults. Associations between albuminuria, which is categorized using urinary albumin-to-creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), and SCD were assessed independently and in combination.ResultsAfter median follow-up of 6.1 years, we identified 335 SCD events. Compared to participants with ACR 30 mg/g, HR 1.56, 95% CI 1.17-2.11). In contrast, compared to the group with eGFR >90 mL/min/1.73 m2, the adjusted risk of SCD was significantly elevated only among those with eGFR 30 mg/g (n = 4040 [14.8%] were far more common. In the analysis that combined ACR and eGFR categories, albuminuria consistently identified individuals with eGFR ≥60 mLmin/1.73 m2 who were at significantly increased SCD risk.ConclusionLow levels of kidney injury as measured by ACR predict an increase in SCD risk.

Mediation analysis is an increasingly popular statistical method for explaining causal pathways to inform intervention. While methods have increased, there is still a dearth of robust mediation methods for count outcomes with excess zeroes. Current mediation methods addressing this issue are computationally intensive, biased, or challenging to interpret. To overcome these limitations, we propose a new mediation methodology for zero‐inflated count outcomes using the marginalized zero‐inflated Poisson (MZIP) model and the counterfactual approach to mediation. This novel work gives population‐average mediation effects whose variance can be estimated rapidly via delta method. This methodology is extended to cases with exposure‐mediator interactions. We apply this novel methodology to explore if diabetes diagnosis can explain BMI differences in healthcare utilization and test model performance via simulations comparing the proposed MZIP method to existing zero‐inflated and Poisson methods. We find that our proposed method minimizes bias and computation time compared to alternative approaches while allowing for straight‐forward interpretations. [ABSTRACT FROM AUTHOR]