FIT calculator: a multi-risk prediction framework for medical outcomes using cardiorespiratory fitness data.

Accurately predicting patients' risk for specific medical outcomes is paramount for effective healthcare management and personalized medicine. While a substantial body of literature addresses the prediction of diverse medical conditions, existing models predominantly focus on singular outcomes, limiting their scope to one disease at a time. However, clinical reality often entails patients concurrently facing multiple health risks across various medical domains. In response to this gap, our study proposes a novel multi-risk framework adept at simultaneous risk prediction for multiple clinical outcomes, including diabetes, mortality, and hypertension. Leveraging a concise set of features extracted from patients' cardiorespiratory fitness data, our framework minimizes computational complexity while maximizing predictive accuracy. Moreover, we integrate a state-of-the-art instance-based interpretability technique into our framework, providing users with comprehensive explanations for each prediction. These explanations afford medical practitioners invaluable insights into the primary health factors influencing individual predictions, fostering greater trust and utility in the underlying prediction models. Our approach thus stands to significantly enhance healthcare decision-making processes, facilitating more targeted interventions and improving patient outcomes in clinical practice. Our prediction framework utilizes an automated machine learning framework, Auto-Weka, to optimize machine learning models and hyper-parameter configurations for the simultaneous prediction of three medical outcomes: diabetes, mortality, and hypertension. Additionally, we employ a local interpretability technique to elucidate predictions generated by our framework. These explanations manifest visually, highlighting key attributes contributing to each instance's prediction for enhanced interpretability. Using automated machine learning techniques, the models simultaneously predict hypertension, mortality, and diabetes risks, utilizing only nine patient features. They achieved an average AUC of 0.90 ± 0.001 on the hypertension dataset, 0.90 ± 0.002 on the mortality dataset, and 0.89 ± 0.001 on the diabetes dataset through tenfold cross-validation. Additionally, the models demonstrated strong performance with an average AUC of 0.89 ± 0.001 on the hypertension dataset, 0.90 ± 0.001 on the mortality dataset, and 0.89 ± 0.001 on the diabetes dataset using bootstrap evaluation with 1000 resamples.

Interhospital Variability in Cardiac Rehabilitation Use After Cardiac Surgery Among Medicare Beneficiaries.

OBJECTIVE: Despite guideline recommendation, cardiac rehabilitation (CR) following cardiac surgery remains underutilized, and the extent of interhospital variability is not well understood. This study evaluated determinants of interhospital variability in CR use and outcomes. METHODS: This retrospective cohort study included 166,809 Medicare beneficiaries undergoing cardiac surgery who were discharged alive between 07/01/2016 and 12/31/2018. CR participation was identified in outpatient facility claims within a year of discharge. Hospital-level CR rates were tabulated, and multilevel models evaluated the extent to which patient, organizational, and regional factors accounted for interhospital variability. Adjusted 1-year mortality and readmission rates were also calculated for each hospital quartile of CR use. RESULTS: Overall, 90,171 (54.1%) participated in at least one CR session within a year of discharge. Interhospital CR rates ranged from 0.0% to 96.8%. Hospital factors that predicted CR use included non-teaching status and lower hospital volume. Before adjusting for patient, organizational, and regional factors, 19.3% of interhospital variability was attributable to the admitting hospital. After accounting for covariates, 12.3% of variation was attributable to the admitting hospital. Patient (0.5%), structural (2.8%), and regional (3.7%) factors accounted for the remaining explained variation. Hospitals in the lowest quartile of CR use had higher adjusted 1-year mortality rates (Q1 = 6.7%, Q4 = 5.2%, p < 0.001) and readmission rates (Q1 = 37.6%, Q4 = 33.9%, p<0.001). CONCLUSION: Identifying best practices among high CR use facilities and barriers to access in low CR use hospitals may reduce interhospital variability in CR use and advance national improvement efforts.

The iATTEND Trial: A Trial Comparing Hybrid Versus Standard Cardiac Rehabilitation.

The improving ATTENDance (iATTEND) to cardiac rehabilitation (CR) trial tested the hypotheses that hybrid CR (HYCR) (combination of virtual and in-facility CR sessions) would result in greater attendance compared with traditional, facility-based only CR (FBCR) and yield equivalent improvements in exercise capacity and health status. Patients were randomized to HYCR (n = 142) or FBCR (n = 140), stratified by gender and race. Attendance was assessed as number of CR sessions completed within 6 months (primary end point) and the percentage of patients completing 36 CR sessions. Other end points (tested for equivalency) included exercise capacity and self-reported health status. HYCR patients completed 1 to 12 sessions in-facility, with the balance completed virtually using synchronized, 2-way audiovisual technology. Neither total number of CR sessions completed within 6 months (29 ± 12 vs 28 ± 12 visits, adjusted p = 0.94) nor percentage of patients completing 36 sessions (59 ± 4% vs 51 ± 4%, adjusted p = 0.32) were significantly different between HYCR and FBCR, respectively. The between-group changes for exercise capacity (peak oxygen uptake, 6-minute walk distance) and health status were equivalent. Regarding safety, no sessions required physician involvement, there was 1 major adverse event after a virtual session, and no falls required medical attention. In conclusion, although we rejected our primary hypothesis that attendance would be greater with HYCR versus FBCR, we showed that FBCR and HYCR resulted in similar patient attendance patterns and equivalent improvements in exercise capacity and health status. HYCR which incorporates virtually supervised exercise should be considered an acceptable alternative to FBCR. NCT Identifier: 03646760; The Improving ATTENDance to Cardiac Rehabilitation Trial - Full-Text View - ClinicalTrials. gov; https://classic.clinicaltrials.gov/ct2/show/NCT03646760.

The relationship between discharge location and cardiac rehabilitation use after cardiac surgery.

BACKGROUND: Cardiac rehabilitation (CR) is a guideline-recommended risk-reduction program offered to cardiac surgical patients. Despite CR's association with better outcomes, attendance remains poor. The relationship between discharge location and CR use is poorly understood. METHODS: This study was a nationwide, retrospective cohort analysis of Medicare fee-for-service claims for beneficiaries undergoing coronary artery bypass grafting and/or surgical aortic valve repair between July 1, 2016, and December 31, 2018. The primary outcome was attendance of any CR session. Discharge location was categorized as home discharge or discharge to extended care facility (ECF) (including skilled nursing facility, inpatient rehabilitation, and long-term acute care). Multivariable logistic regression models evaluated the association between discharge location, CR attendance, and 1-year mortality. RESULTS: Of the 167,966 patients who met inclusion criteria, 34.1% discharged to an ECF. Overall CR usage rate was 53.9%. Unadjusted and adjusted CR use was lower among patients discharged ECFs versus those discharged home (42.1% vs 60.0%; adjusted odds ratio, 0.66; P < .001). Patients discharged to long-term acute care were less likely to use CR than those discharged to skilled nursing facility or inpatient rehabilitation (reference category: home; adjusted odds ratio for long-term acute care, 0.36, adjusted odds ratio for skilled nursing facility, 0.69, and adjusted odds ratio for inpatient rehabilitation, 0.71; P < .001). CR attendance was associated with a greater reduction in adjusted 1-year mortality in patients discharged to ECFs (9.7% reduction) versus those discharged home (4.3% reduction). CONCLUSIONS: In this national analysis of Medicare beneficiaries, discharge to ECF was associated with lower CR use, despite a greater association with improved 1-year mortality. Interventions aimed at increasing CR enrollment at ECFs may improve CR use and advance surgical quality.

Bridge to Weight Loss: A Case Series.

Durable left ventricular assist devices (LVADs) are a well-established therapeutic option for patients with advanced heart failure. These devices are often used to "bridge" patients to an orthotopic heart transplantation (HT). Unfortunately, many patients on LVAD support with a body mass index (BMI) above a certain value are not eligible for HT due a lack of suitable donors and the association between obesity and poor outcomes after HT. This case series describes three individuals on LVAD support who were able to successfully lose enough weight to qualify to be listed for an HT. We highlight a systematic, multidisciplinary approach to implementing guideline-driven weight loss strategies, including some aggressive methods (ie, meal replacements, weight loss medications, and bariatric surgery). In addition to describing the weight loss outcomes, we also discuss barriers and medical challenges during weight loss that are unique to this population.

Cardiac Rehabilitation Use After Heart Failure Hospitalization Associated With Advanced Heart Failure Center Status.

PURPOSE: Cardiac rehabilitation (CR) is an evidence-based, guideline-endorsed therapy for patients with heart failure with reduced ejection fraction (HFrEF) but is broadly underutilized. Identifying structural factors contributing to increased CR use may inform quality improvement efforts. The objective here was to associate hospitalization at a center providing advanced heart failure (HF) therapies and subsequent CR participation among patients with HFrEF. METHODS: A retrospective analysis was performed on a 20% sample of Medicare beneficiaries primarily hospitalized with an HFrEF diagnosis between January 2008 and December 2018. Outpatient claims were used to identify CR use (no/yes), days to first session, number of attended sessions, and completion of 36 sessions. The association between advanced HF status (hospitals performing heart transplantation or ventricular assist device implantations) and CR participation was evaluated with logistic regression, accounting for patient, hospital, and regional factors. RESULTS: Among 143 392 Medicare beneficiaries, 29 487 (20.6%) were admitted to advanced HF centers (HFCs) and 5317 (3.7%) attended a single CR session within 1 yr of discharge. In multivariable analysis, advanced HFC status was associated with significantly greater relative odds of participating in CR (OR = 2.20: 95% CI, 2.08-2.33; P < .001) and earlier initiation of CR participation (-8.5 d; 95% CI, -12.6 to 4.4; P < .001). Advanced HFC status had little to no association with the intensity of CR participation (number of visits or 36 visit completion). CONCLUSIONS: Medicare beneficiaries hospitalized for HF were more likely to attend CR after discharge if admitted to an advanced HFC than a nonadvanced HFC.

Relationship Between Community-Level Distress and Cardiac Rehabilitation Participation, Facility Access, and Clinical Outcomes After Inpatient Coronary Revascularization.

BACKGROUND: Although disparities in cardiac rehabilitation (CR) participation are well documented, the role of community-level distress is poorly understood. This study evaluated the relationship between community-level distress and CR participation, access to CR facilities, and clinical outcomes. METHODS: A retrospective cohort study was conducted on a 100% sample of Medicare beneficiaries undergoing inpatient coronary revascularization between July 2016 and December 2018. Community-level distress was defined using the Distressed Community Index quintile at the beneficiary zip code level, with the first and fifth quintiles representing prosperous and distressed communities, respectively. Outpatient claims were used to identify any CR use within 1 year of discharge. Beneficiary and CR facility zip codes were used to describe access to CR facilities. Adjusted logistic regression models evaluated the association between Distressed Community Index quintiles, CR use, and clinical outcomes, including one-year mortality, all-cause hospitalization, and acute myocardial infarction hospitalization. RESULTS: A total of 414 730 beneficiaries were identified, with 96 929 (23.4%) located in the first and 67 900 (16.4%) in the fifth quintiles, respectively. Any CR use was lower for beneficiaries in distressed compared with prosperous communities (26.0% versus 46.1%, P<0.001), which was significant after multivariable adjustment (odds ratio, 0.41 [95% CI, 0.40-0.42]). A total of 98 458 (23.7%) beneficiaries had a CR facility within their zip code, which increased from 16.3% in prosperous communities to 26.6% in distressed communities. Any CR use was associated with absolute reductions in mortality (-6.8% [95% CI, -7.0% to -6.7%]), all-cause hospitalization (-5.9% [95% CI, -6.3% to -5.6%]), and acute myocardial infarction hospitalization (-1.3% [95% CI, -1.5% to -1.1%]), which were similar across each Distressed Community Index quintiles. CONCLUSIONS: Although community-level distress was associated with lower CR participation, the clinical benefits were universally received. Addressing barriers to CR in distressed communities should be considered a significant priority to improve survival after coronary revascularization and reduce disparities.

Cardiac Rehabilitation Reduces 2-Year Mortality After Coronary Artery Bypass Grafting.

BACKGROUND: Cardiac rehabilitation (CR) is a supervised outpatient exercise and risk reduction program offered to patients who have undergone coronary revascularization procedures. Multiple professional societal guidelines support the use of CR after coronary artery bypass grafting (CABG) based on studies in combined percutaneous coronary intervention and CABG populations with surrogate outcomes. This statewide analysis of patients undergoing CABG evaluated the relationship between CR use and long-term mortality. METHODS: Medicare fee-for-service claims were linked to surgical data for patients discharged alive after isolated CABG from January 1, 2015, through September 30, 2019. Outpatient facility claims were used to identify any CR use within 1 year of discharge. Death within 2 years of discharge was the primary outcome. Mixed-effects logistic regression was used to predict CR use, adjusting for a variety of comorbidities. Unadjusted and inverse probability treatment weighting (IPTW) were used to compare 2-year mortality among CR users vs nonusers. RESULTS: A total of 3848 of 6412 patients (60.0%) were enrolled in CR for an average of 23.2 (SD, 12.0) sessions, with 770 of 6412 (12.0%) completing all recommended 36 sessions. Logistic regression identified increasing age, discharge to home (vs extended care facility), and shorter length of stay as predictors of postdischarge CR use (P < .05). Unadjusted and IPTW analyses showed significant reduction in 2-year mortality in CR users compared with CR nonusers (unadjusted: 9.4% reduction; 95% CI, 10.8%-7.9%; P < .001; IPTW: -4.8% reduction; 95% CI, 6.0%-3.5%; P < .001). CONCLUSIONS: These data suggest that CR use is associated with lower 2-year mortality. Future quality initiatives should consider identifying and addressing root causes of poor CR enrollment and completion.

Improved cardiorespiratory fitness is associated with lower incident ischemic stroke risk: Henry Ford FIT project.

BACKGROUND: Change in cardiorespiratory fitness (CRF) modulates vascular disease risk; however, it's unclear if this adds further prognostic information, particularly for ischemic stroke. The objective of this analysis is to describe the association between the change in CRF over time and subsequent incident ischemic stroke. METHODS: This is a retrospective, longitudinal, observational cohort study of 9,646 patients (age=55±11 years; 41% women; 25% black) who completed 2 clinically indicated exercise tests (> 12 months apart) and were free of any stroke at the time of test 2. CRF was expressed as metabolic-equivalents-of-task (METs). Incident ischemic stroke was identified using ICD codes. The adjusted hazard ratio (aHR) was determined for risk of ischemic stroke associated with change in CRF. RESULTS: Mean time between tests was 3.7 years (IQR, 2.2, 6.0). During a median of 5.0 years (IQR, 2.7, 7.6 y) of follow-up, there were 873 (9.1%) ischemic stroke events. Each 1 MET increase between tests was associated with a 9% lower ischemic stroke risk (aHR 0.91 [0.88-0.94]; n = 9.646). There was an interaction effect by baseline CRF category, but not for sex or race. A sensitivity analysis which removed those who experienced an incident diagnosis known to be associated with an increased risk of ischemic vascular disease, validated our primary findings (aHR 0.91 [0.88, 0.95]; n= 6,943). CONCLUSIONS: Improvement in CRF over time is independently and inversely associated with a lower risk of ischemic stroke. Encouragement of regular exercise focused on improving CRF may reduce ischemic stroke risk.

Among Patients Taking Beta-Adrenergic Blockade Therapy, Use Measured (Not Predicted) Maximal Heart Rate to Calculate a Target Heart Rate for Cardiac Rehabilitation.

PURPOSE: Among patients in cardiac rehabilitation (CR) on beta-adrenergic blockade (ßB) therapy, this study describes the frequency for which target heart rate (THR) values computed using a predicted maximal heart rate (HR max ), correspond to a THR computed using a measured HR max in the guideline-based heart rate reserve (HR reserve ) method. METHODS: Before CR, patients completed a cardiopulmonary exercise test to measure HR max , with the data used to determine THR via the HR reserve method. Additionally, predicted HR max was computed for all patients using the 220 - age equation and two disease-specific equations, with the predicted values used to calculate THR via the straight percent and HR reserve methods. The THR was also computed using resting heart rate (HR) +20 and +30 bpm. RESULTS: Mean predicted HR max using the 220 - age equation (161 ± 11 bpm) and the disease-specific equations (123 ± 9 bpm) differed ( P < .001) from measured HR max (133 ± 21 bpm). Also, THR computed using predicted HR max resulted in values that were infrequently within the guideline-based HR reserve range calculated using measured HR max . Specifically, 0 to ≤61% of patients would have had an exercise training HR that fell within the guideline-based range of 50-80% of measured HR reserve . Use of standing resting HR +20 or +30 bpm would have resulted in 100% and 48%, respectively, of patients exercising below 50% of HR reserve . CONCLUSIONS: A THR computed using either predicted HR max or resting HR +20 or +30 bpm seldom results in a prescribed exercise intensity that is consistent with guideline recommendations for patients in CR.

Comorbidities are associated with state hopelessness in adults with ischemic heart disease.

BACKGROUND: In adults with ischemic heart disease (IHD), comorbidities and hopelessness are independently associated with increased risk of mortality. OBJECTIVES: To determine if comorbidities were associated with state and trait hopelessness and explore the influence of specific conditions and hopelessness in individuals hospitalized for IHD. METHODS: Participants completed the State-Trait Hopelessness Scale. Charlson Comorbidity Index (CCI) scores were generated from the medical record. A chi-squared test was used to examine differences in 14 diagnoses included in the CCI by CCI severity. Unadjusted and adjusted linear models were used to explore the relationship between hopelessness levels and the CCI. RESULTS: Participants (n=132) were predominantly male (68.9%), with a mean age of 62.6 years, and majority white (97%). The mean CCI was 3.5 (range 0-14), with 36.4% having a score of 1-2 (mild), 41.2% with a score of 3-4 (moderate) and 22.7% with a score of ≥5 (severe). The CCI was positively associated with both state (ß=0.03; 95% CI 0.01, 0.05; p=0.002) and trait (ß=0.04; 95% CI 0.01, 0.06; p=0.007) hopelessness in unadjusted models. The relationship for state hopelessness remained significant after adjusting for multiple demographic characteristics (ß=0.03; 95% CI 0.01, 0.05; p=0.02), while trait hopelessness did not. Interaction terms were evaluated, and findings did not differ by age, sex, education level, or diagnosis/type of intervention. CONCLUSION: Hospitalized individuals with IHD with a higher number of comorbidities may benefit from targeted assessment and brief cognitive intervention to identify and ameliorate state hopelessness which has been associated with worse long-term outcomes.

Supervised Exercise Training for Chronic Heart Failure With Preserved Ejection Fraction: A Scientific Statement From the American Heart Association and American College of Cardiology.

Heart failure with preserved ejection fraction (HFpEF) is one of the most common forms of heart failure; its prevalence is increasing, and outcomes are worsening. Affected patients often experience severe exertional dyspnea and debilitating fatigue, as well as poor quality of life, frequent hospitalizations, and a high mortality rate. Until recently, most pharmacological intervention trials for HFpEF yielded neutral primary outcomes. In contrast, trials of exercise-based interventions have consistently demonstrated large, significant, clinically meaningful improvements in symptoms, objectively determined exercise capacity, and usually quality of life. This success may be attributed, at least in part, to the pleiotropic effects of exercise, which may favorably affect the full range of abnormalities-peripheral vascular, skeletal muscle, and cardiovascular-that contribute to exercise intolerance in HFpEF. Accordingly, this scientific statement critically examines the currently available literature on the effects of exercise-based therapies for chronic stable HFpEF, potential mechanisms for improvement of exercise capacity and symptoms, and how these data compare with exercise therapy for other cardiovascular conditions. Specifically, data reviewed herein demonstrate a comparable or larger magnitude of improvement in exercise capacity from supervised exercise training in patients with chronic HFpEF compared with those with heart failure with reduced ejection fraction, although Medicare reimbursement is available only for the latter group. Finally, critical gaps in implementation of exercise-based therapies for patients with HFpEF, including exercise setting, training modalities, combinations with other strategies such as diet and medications, long-term adherence, incorporation of innovative and more accessible delivery methods, and management of recently hospitalized patients are highlighted to provide guidance for future research.

Supervised Exercise Training for Chronic Heart Failure With Preserved Ejection Fraction: A Scientific Statement From the American Heart Association and American College of Cardiology.

Heart failure with preserved ejection fraction (HFpEF) is one of the most common forms of heart failure; its prevalence is increasing, and outcomes are worsening. Affected patients often experience severe exertional dyspnea and debilitating fatigue, as well as poor quality of life, frequent hospitalizations, and a high mortality rate. Until recently, most pharmacological intervention trials for HFpEF yielded neutral primary outcomes. In contrast, trials of exercise-based interventions have consistently demonstrated large, significant, clinically meaningful improvements in symptoms, objectively determined exercise capacity, and usually quality of life. This success may be attributed, at least in part, to the pleiotropic effects of exercise, which may favorably affect the full range of abnormalities-peripheral vascular, skeletal muscle, and cardiovascular-that contribute to exercise intolerance in HFpEF. Accordingly, this scientific statement critically examines the currently available literature on the effects of exercise-based therapies for chronic stable HFpEF, potential mechanisms for improvement of exercise capacity and symptoms, and how these data compare with exercise therapy for other cardiovascular conditions. Specifically, data reviewed herein demonstrate a comparable or larger magnitude of improvement in exercise capacity from supervised exercise training in patients with chronic HFpEF compared with those with heart failure with reduced ejection fraction, although Medicare reimbursement is available only for the latter group. Finally, critical gaps in implementation of exercise-based therapies for patients with HFpEF, including exercise setting, training modalities, combinations with other strategies such as diet and medications, long-term adherence, incorporation of innovative and more accessible delivery methods, and management of recently hospitalized patients are highlighted to provide guidance for future research.

Cardiac Rehabilitation Improves Fitness in Patients With Subclinical Markers of Cardiotoxicity While Receiving Chemotherapy: A RANDOMIZED CONTROLLED STUDY.

PURPOSE: Heart failure (HF) due to cardiotoxicity is a leading non-cancer-related cause of morbidity and mortality in cancer survivors. Cardiac rehabilitation (CR) improves cardiorespiratory fitness (CRF) and reduces morbidity and mortality in patients with HF, but little is known about its effects on cardiotoxicity in the cancer population. The objective of this study was to determine whether participation in CR improves CRF in patients undergoing treatment with either doxorubicin or trastuzumab who exhibit markers of subclinical cardiotoxicity. METHODS: Female patients with cancer (n = 28: breast, n = 1: leiomyosarcoma) and evidence of subclinical cardiotoxicity (ie, >10% relative decrease in global longitudinal strain or a cardiac troponin of >40 ng·L -1 ) were randomized to 10 wk of CR or usual care. Exercise consisted of 3 d/wk of interval training at 60-90% of heart rate reserve. RESULTS: Cardiorespiratory fitness, as measured by peak oxygen uptake (V˙ o2peak ), improved in the CR group (16.9 + 5.0 to 18.5 + 6.0 mL∙kg -1 ∙min -1 ) while it decreased in the usual care group (17.9 + 3.9 to 16.9 + 4.0 mL∙kg -1 ∙min -1 ) ( P = .009). No changes were observed between groups with respect to high-sensitivity troponin or global longitudinal strain. CONCLUSION: This study suggests that the use of CR may be a viable option to attenuate the reduction in CRF that occurs in patients undergoing cardiotoxic chemotherapy. The long-term effects of exercise on chemotherapy-induced HF warrant further investigation.

Cardiac Rehabilitation and the COVID-19 Pandemic: Persistent Declines in Cardiac Rehabilitation Participation and Access Among US Medicare Beneficiaries.

BACKGROUND: The impact of the COVID-19 pandemic on participation in and availability of cardiac rehabilitation (CR) is unknown. METHODS: Among eligible Medicare fee-for-service beneficiaries, we evaluated, by month, the number of CR sessions attended per 100 000 beneficiaries, individuals eligible to initiate CR, and centers offering in-person CR between January 2019 and December 2021. We compared these outcomes between 2 periods: December 1, 2019 through February 28, 2020 (period 1, before declaration of the pandemic-related national emergency) and October 1, 2021 through December 31, 2021 (period 2, the latest period for which data are currently available). RESULTS: In period 1, Medicare beneficiaries participated in (mean±SD) 895±84 CR sessions per 100 000 beneficiaries each month. After the national emergency was declared, CR participation sharply declined to 56 CR sessions per 100 000 beneficiaries in April 2020. CR participation recovered gradually through December 2021 but remained lower than prepandemic levels (period 2: 698±29 CR sessions per month per 100 000 beneficiaries, P=0.02). Declines in CR participation were most marked among dual Medicare and Medicaid enrollees and patients residing in rural areas or socially vulnerable communities. There was no statistically significant change in CR eligibility between the 2 periods. Compared with 2618±5 CR centers in period 1, there were 2464±7 in period 2 (P<0.01). Compared with CR centers that survived the pandemic, 220 CR centers that closed were more likely to be affiliated with public hospitals, located in rural areas, and serve the most socially vulnerable communities. CONCLUSIONS: The COVID-19 pandemic was associated with a persistent decline in CR participation and the closure of CR centers, which disproportionately affected rural and low-income patients and the most socially vulnerable communities. Innovation in CR financing and delivery is urgently needed to equitably enhance CR participation among Medicare beneficiaries.

Relation of Exercise Capacity to Incident Heart Failure Among Men and Women With Coronary Heart Disease (from the Henry Ford Exercise Testing [FIT] Project).

Exercise capacity (EC) is inversely related to the risk of cardiovascular disease and incident heart failure (HF) in healthy subjects. However, there are no present studies that exclusively evaluate EC and the risk of incident HF in patients with known coronary heart disease (CHD). We aimed to determine the relation between EC and incident HF in patients with an established clinical diagnosis of CHD. We retrospectively identified 8,387 patients (age 61 ± 12 years; 30% women; 33% non-White) with a history of myocardial infarction (MI) or coronary revascularization procedure and no history of HF at the time of a clinically indicated exercise stress test completed between 1991 and 2009. EC was quantified in metabolic equivalents of task (METs) estimated from treadmill testing. Incident HF was identified through June 2010 from administrative databases based on ≥3 encounters with International Classification of Diseases, Ninth Revision 428.x. Cox regression analysis was used to evaluate the risk of incident HF associated with METs. Covariates included age; gender; race; hypertension, diabetes, hyperlipidemia, smoking, and MI; medications for CHD and lung diseases; and clinical indication for treadmill testing. During a median follow-up of 8.2 years (interquartile range 4.7 to 12.4 years) after the exercise test, 23% of the cohort experienced a new HF diagnosis. Lower EC categories were associated with higher HF incidence compared with METs ≥12, with nearly fourfold greater adjusted risk among patients with METs <6. Per unit increase in METs of EC was associated with a 12% lower adjusted risk for HF. There was no significant interaction based on race (p = 0.06), gender (p = 0.88), age ≤61 years (p = 0.60), history of MI (p = 0.31), or diabetes (p = 0.38). This study reveals that among men and women with CHD and no history of HF, EC is independently and inversely related to the risk of future HF.