2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

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.

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.

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.

Relation of a Maximal Exercise Test to Change in Exercise Tolerance During Cardiac Rehabilitation

The purpose of this study was to test the hypothesis that an individualized exercise training target heart rate (HR) based on a maximal graded exercise test (GXT) is associated with greater improvements in exercise tolerance during cardiac rehabilitation (CR) compared with no GXT. In this retrospective study, we identified patients who completed 9 to 36 visits of CR between 2001 and 2016, with a length of stay ≤18 weeks and a visit frequency of 1 to 3 days per week. Patients were grouped based on whether their exercise was guided by a target HR determined from a GXT. To assess the relation between GXT and change in exercise training metabolic equivalents of task (METs), we used generalized linear models adjusted for age, gender, race, referral reason, CR visits, CR frequency, METs at start, CR location, and year of participation. Out of 4,455 patients (37% female, 48% White, median age = 62 years), 53% were prescribed a target HR based on a GXT. Compared with no GXT, a GXT was associated with a significantly greater increase in covariate-adjusted METs during CR and percentage change from start (+0.44 METs [95% confidence interval [CI] 0.38 to 0.51] and +17% [95% CI 14% to 19%], respectively). In a sensitivity analysis limited to patients with 24 to 36 visits at ≥2 days per week (n = 1,319), a GXT was associated with a significantly greater increase in covariate-adjusted exercise training METs (+0.51 [95% CI 0.36 to 0.66]; +19% [95% CI 13% to 24%]). In conclusion, to maximize the potential increase in exercise capacity during CR, patients should undergo a GXT to determine an individualized exercise training target HR.

Decision Aids for Determining Facility Versus Non-Facility-Based Exercise in Those with Symptomatic Peripheral Artery Disease

Purpose of Review

This paper sought to provide rationale for determining when a patient with symptomatic peripheral artery disease (PAD) might be referred for home-based versus facility-based exercise therapy.

Recent Findings

Multiple randomized controlled studies have embedded supervised, structured exercise therapy as a class IA recommended therapy for those with symptomatic PAD. More recently, there is interest in non-facility-based exercise training as an alternative. The current literature is mixed on the effectiveness of non-facility-based training and is influenced by the amount of contact with clinical staff providing some supervision (e.g., occasional facility-based exercise or coaching phone calls), and the intensity (e.g., performed intermittently by inducing pain or continually and not inducing pain) and frequency (e.g., 12-week common supervised exercise program or those longer than 24 weeks) of exercise. Certainly, the data suggests non-facility-based exercise, while possibly improving walking performance, is inferior to facility-based supervised exercise training. Comprehensive data is lacking on utilization of supervised exercise therapy in those with symptomatic PAD, but is likely <2% of those eligible who participate. This suggests a possible important role for alternatives including non-facility-based (e.g., home, fitness center).

Summary

Exercise training in the supervised, facility-based setting appears to be greatly underutilized. Non-facility-based exercise may help to overcome some of the most common barriers to participating in facility-based exercise including those related to motivation, transportation, and proximity. However, facility-based training is considered the gold standard so decisions about allowing a patient to exercise train at home must take into account issues including disease severity, patient motivation and available exercise resources, mobility and balance, cognitive function, and other medical concerns (e.g., symptomatic coronary artery disease or heart failure).

Prognostic Value of Cardiorespiratory Fitness in Patients with Chronic Kidney Disease: The FIT (Henry Ford Exercise Testing) Project

PURPOSE

We conducted this study to investigate the association of cardiorespiratory fitness and all-cause mortality among patients with chronic kidney disease.

METHODS

We studied a retrospective cohort of patients from the Henry Ford Health System who underwent clinically indicated exercise stress testing with baseline cardiorespiratory fitness and estimated glomerular filtration rate measurement. Cardiorespiratory fitness was expressed as metabolic equivalents of task, and kidney function was categorized into stages according to estimated glomerular filtration rate. Multivariable-adjusted Cox proportional hazard models were used to examine the association between metabolic equivalents of task and all-cause mortality among patients with chronic kidney disease stages 3-5. Discrimination of mortality was assessed using receiver operating characteristic curves, while reclassification was evaluated using net reclassification index (NRI).

RESULTS

Among 50,121 participants, the mean age was 55 ± 12.6 years; 47.5% were women, 64.5% were white, and 6877 (13.7%) participants had chronic kidney disease stage 3-5. Over a median follow-up of 6.7 years, 6308 participants died (12.6%). Each 1-unit higher metabolic equivalents of task was associated with a significant 15% reduction in all-cause mortality (hazard ratio 0.85; 95% confidence interval [CI], 0.84-0.87). Metabolic equivalents of task improved discriminatory ability of mortality prediction when added to traditional risk factors and estimated glomerular filtration rate (area under the curve 0.7996; 95% CI, 0.789-0.810 vs 0.759; 95% CI, 0.748-0.770, respectively; P < .001). The addition of metabolic equivalents of task to traditional risk factors resulted in significant reclassification (6% for events, 5% for non-events: NRI = 0.13, P < .001).

CONCLUSIONS

Cardiorespiratory fitness improves mortality risk prediction among patients with chronic kidney disease. Cardiorespiratory fitness provides incremental prognostic information when added to traditional risk factors and may help guide treatment options among patients with renal dysfunction.

Rethinking Rehabilitation: A REVIEW OF PATIENT POPULATIONS WHO CAN BENEFIT FROM CARDIAC REHABILITATION

Although cardiac rehabilitation (CR) is safe and highly effective for individuals with various cardiovascular health conditions, to date there are only seven diagnoses or procedures identified by the Centers for Medicare & Medicaid Services that qualify for referral. When considering the growing number of individuals with cardiovascular disease (CVD), or other health conditions that increase the risk for CVD, it is important to determine the extent for which CR could benefit these populations. Furthermore, there are some patients who may currently be eligible for CR (spontaneous coronary artery dissection, left ventricular assistant device) but make up a relatively small proportion of the populations that are regularly attending and participating. Thus, these patient populations and special considerations for exercise might be less familiar to professionals who are supervising their programs. The purpose of this review is to summarize the current literature surrounding exercise testing and programming among four specific patient populations that either do not currently qualify for (chronic and end-stage renal disease, breast cancer survivor) or who are eligible but less commonly seen in CR (sudden coronary artery dissection, left ventricular assist device). While current evidence suggests that individuals with these health conditions can safely participate in and may benefit from supervised exercise programming, there is an immediate need for high-quality, multisite clinical trials to develop more specific exercise recommendations and support the inclusion of these populations in future CR programs.

Fitness and Mortality Among Persons 70 Years and Older Across the Spectrum of Cardiovascular Disease Risk Factor Burden: The FIT Project

OBJECTIVE

To determine whether fitness could improve mortality risk stratification among older adults compared with cardiovascular disease (CVD) risk factors.

METHODS

We examined 6509 patients 70 years of age and older without CVD from the Henry Ford ExercIse Testing Project (FIT Project) cohort. Patients performed a physician-referred treadmill stress test between 1991 and 2009. Traditional categorical CVD risk factors (hypertension, hyperlipidemia, diabetes, and smoking) were summed from 0 to 3 or more. Fitness was grouped as low, moderate, and high (<6, 6 to 9.9, and ≥10 metabolic equivalents of task). All-cause mortality was ascertained through US Social Security Death Master files. We calculated age-adjusted mortality rates, multivariable adjusted Cox proportional hazards, and Kaplan-Meier survival models.

RESULTS

Patients had a mean age of 75±4 years, and 3385 (52%) were women; during a mean follow-up of 9.4 years, there were 2526 deaths. A higher fitness level (P<.001), not lower CVD risk factor burden (P=.31), was associated with longer survival. The age-adjusted mortality rate per 1000 person-years was 56.7 for patients with low fitness and 0 risk factors compared with 24.9 for high fitness and 3 or more risk factors. Among patients with 3 or more risk factors, the adjusted mortality hazard was 0.68 (95% CI, 0.61 to 0.76) for moderate and 0.51 (95% CI, 0.44 to 0.60) for high fitness compared with the least fit.

CONCLUSION

Among persons aged 70 years and older, there was no significant difference in survival of patients with 0 vs 3 or more risk factors, but a higher fitness level identified older persons with good long-term survival regardless of CVD risk factor burden.

Fitness and prostate cancer screening, incidence, and mortality: Results from the Henry Ford Exercise Testing (FIT) Project

BACKGROUND

The relation between cardiorespiratory fitness (CRF) and prostate cancer is not well established. The objective of this study was to determine whether CRF is associated with prostate cancer screening, incidence, or mortality.

METHODS

The Henry Ford Exercise Testing Project is a retrospective cohort study of men aged 40 to 70 years without cancer who underwent physician-referred exercise stress testing from 1995 to 2009. CRF was quantified in metabolic equivalents of task (METs) (<6 [reference], 6-9, 10-11, and ≥12 METs), estimated from the peak workload achieved during a symptom-limited, maximal exercise stress test. Prostate-specific antigen (PSA) testing, incident prostate cancer, and all-cause mortality were analyzed with multivariable adjusted Poisson regression and Cox proportional hazard models.

RESULTS

In total, 22,827 men were included, of whom 739 developed prostate cancer, with a median follow-up of 7.5 years. Men who had high fitness (≥12 METs) had an 28% higher risk of PSA screening (95% CI, 1.2-1.3) compared with those who had low fitness (<6 METs. After adjusting for PSA screening, fitness was associated with higher prostate cancer incidence (men aged <55 years, P = .02; men aged >55 years, P ≤ .01), but not with advanced prostate cancer. Among the men who were diagnosed with prostate cancer, high fitness was associated with a 60% lower risk of all-cause mortality (95% CI, 0.2-0.9).

CONCLUSIONS

Although men with high fitness are more likely to undergo PSA screening, this does not fully account for the increased incidence of prostate cancer seen among these individuals. However, men with high fitness have a lower risk of death after a prostate cancer diagnosis, suggesting that the cancers identified may be low-risk with little impact on long-term outcomes.

Inverse Relationship of Maximal Exercise Capacity to Hospitalization Secondary to Coronavirus Disease 2019

OBJECTIVE

To investigate the relationship between maximal exercise capacity measured before severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and hospitalization due to coronavirus disease 2019 (COVID-19).

METHODS

We identified patients (≥18 years) who completed a clinically indicated exercise stress test between January 1, 2016, and February 29, 2020, and had a test for SARS-CoV-2 (ie, real-time reverse transcriptase polymerase chain reaction test) between February 29, 2020, and May 30, 2020. Maximal exercise capacity was quantified in metabolic equivalents of task (METs). Logistic regression was used to evaluate the likelihood that hospitalization secondary to COVID-19 is related to peak METs, with adjustment for 13 covariates previously identified as associated with higher risk for severe illness from COVID-19.

RESULTS

We identified 246 patients (age, 59±12 years; 42% male; 75% black race) who had an exercise test and tested positive for SARS-CoV-2. Among these, 89 (36%) were hospitalized. Peak METs were significantly lower (P<.001) among patients who were hospitalized (6.7±2.8) compared with those not hospitalized (8.0±2.4). Peak METs were inversely associated with the likelihood of hospitalization in unadjusted (odds ratio, 0.83; 95% CI, 0.74-0.92) and adjusted models (odds ratio, 0.87; 95% CI, 0.76-0.99).

CONCLUSION

Maximal exercise capacity is independently and inversely associated with the likelihood of hospitalization due to COVID-19. These data further support the important relationship between cardiorespiratory fitness and health outcomes. Future studies are needed to determine whether improving maximal exercise capacity is associated with lower risk of complications due to viral infections, such as COVID-19.

Abstract 4348: Cardiorespiratory fitness levels in men who develop prostate cancer and its association with all-cause mortality

Background: Cardiorespiratory fitness (CRF) is associated with a reduction in both cancer- and cardiovascular-specific mortality. In men however, little is known about the impact of pre-diagnostic CRF on mortality after prostate cancer. We hypothesized that among men with prostate cancer, low levels of CRF, measured prior to diagnosis, are associated with a higher risk of all-cause mortality.

Methods: From the Henry Ford FIT Project, a cohort of 37,730 men who underwent clinically-indicated exercise stress test from 1991 through 2009, we identified 1,440 men who developed prostate cancer after stress test. CRF was measured in peak metabolic equivalents of task (METs) and categorized as less than 6, 6 to 9, 10 to 11, and at least 12 (reference). Multivariable Cox proportional hazard models were developed to evaluate the association between CRF, measured prior to prostate cancer diagnosis, and all-cause mortality. Models were adjusted for age at prostate cancer diagnosis (baseline), race, BMI, current aspirin and statin use, smoking history, hypertension, diabetes, prior cardiovascular disease (myocardial infarction and heart failure), time from stress test to prostate cancer diagnosis, and cancer stage (local, regional, distant) at diagnosis.

Results: Mean age at time of stress test was 61 +/- 9 yr (57% white, 39% black), with 7 (+/-4) yrs of follow up after prostate cancer diagnosis. 81% of men were diagnosed with localized prostate cancer; 15% with regional disease, and 2% with distant metastatic disease. Mean time from stress test to diagnosis was 6 +/- 5 yrs. Mean METs achieved was 9 (+/- 3). Patients with low fitness (METs less than 6) before diagnosis had 2.6 times the risk of all-cause mortality (95% CI 1.6-4.2) compared to those with high fitness (METS at least 12). Those with CRF of 6-9 METs had 1.9 times the risk (95% CI 1.2-3.0). The risk of mortality was not different between the two highest fitness groups (P= 0.71; P for trend across all fitness groups less than 0.01). Results were similar when stratified by race.

Conclusion: Low CRF prior to the diagnosis of prostate cancer in men is associated with a higher risk of all-cause mortality. This study highlights the prognostic importance of fitness even before a cancer diagnosis.

Citation Format: Cara Reiter-Brennan, Omar Dzaye, Mouaz H. Al-Mallah, Zeina Dardari, Clinton A. Brawner, Lois E. Lamerato, Steven J. Keteyian, Jonathan K. Ehrman, Kala Visvanathan, Michael J. Blaha, Catherine Handy Marshall. Cardiorespiratory fitness levels in men who develop prostate cancer and its association with all-cause mortality [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4348.

Abstract 5773: Cardiorespiratory fitness and PSA screening patterns in the Henry Ford FIT Project

Background: High levels of cardiorespiratory fitness (CRF) have been associated with a decreased risk of many cancers, but the association with prostate cancer (PCa) is less clear. A possible explanation for the lack of consistency is that prostate specific antigen (PSA) screening and in turn prostate cancer detection is more frequent in men with higher fitness although the relationship between fitness and PSA screening is not established.

Methods: The Henry Ford (HF) FIT Project is a retrospective cohort study of 69,894 consecutive patients who underwent physician-referred exercise stress testing from 1991 through 2009. Cancer diagnosis was identified through linkage to the HF tumor registry. We included men aged 40-70 yr who had CRF testing beginning in 1995 (when PSA screening became widespread), without prevalent cancer, followed at least 3 yrs and up to 10 years, who never develop prostate cancer (n=12,442). CRF was measured in metabolic equivalents of task (METs) and categorized as less than 6 (ref), 6-9, 10-11, and at least 12. PSA values were abstracted from the HF electronic medical record between 1995 and 2010. Individuals with at least 3 screening PSA tests were categorized as high screeners. Logistic regression was used to evaluate the relationship between CRF and high PSA screeners, adjusted for age at stress test and race.

Results: Participants had a mean age of 54 ± 8 yrs (67% white; 25% black) and mean follow-up was 7±2 yrs. Compared to individuals with low fitness (less than 6 METs, reference), those with higher fitness (6-9, 10-11, at least 12 METs) had higher odds of being a high PSA screener (Table). When stratified by race, the OR for black patients were not statistically different than white patients (Table). Results were similar among those with comorbidities (myocardial infarction, heart failure, or diabetes) at baseline.

Odds ratio of being a high screener (at least 3 PSA tests) in individuals followed 3-10 yearsMETs categoryAll (n=12,442Whites (n=8,356Blacks (n=3,049)Patients w/comorbidities (n=3,924)&lt;6RefRefRefRef6-91.6(1.3-1.8)1.6(1.3-2.0)1.4(1.1-1.9)1.6(1.3-2.0)10-111.9(1.6-2.2)1.9(1.6-2.4)1.7(1.3-2.2)2.0(1.7-2.4)&gt;=122.4 (2.1-2.9)2.5(2.0-3.1)2.1(1.6-2.8)3.2(2.5-4.0)

Conclusion: High CRF is associated with more frequent PSA screening. This points towards a healthy screening bias and should be accounted for in studies looking at fitness and incident prostate cancer.

Citation Format: Cara Reiter-Brennan, Omar Dzaye, Mouaz H. Al-Mallah, Zeina Dardari, Clinton A. Brawner, Lois E. Lamerato, Steven J. Keteyian, Jonathan K. Ehrman, Kala Visvanathan, Michael J. Blaha, Catherine Handy Marshall. Cardiorespiratory fitness and PSA screening patterns in the Henry Ford FIT Project [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5773.

Cardiorespiratory Fitness and Incident Stroke Types: The FIT (Henry Ford ExercIse Testing) Project

OBJECTIVE

To study the association between cardiorespiratory fitness (CRF) and incident stroke types.

PATIENTS AND METHODS

We studied a retrospective cohort of patients referred for treadmill stress testing in the Henry Ford Health System (Henry Ford ExercIse Testing Project) without history of stroke. CRF was expressed by metabolic equivalents of task (METs). Using appropriate International Classification of Diseases, Ninth Revision codes, incident stroke was ascertained through linkage with administrative claims files and classified as ischemic, hemorrhagic, and subarachnoid hemorrhage (SAH). Multivariable-adjusted Cox proportional hazards models examined the association between CRF and incident stroke.

RESULTS

Among 67,550 patients, mean ± SD age was 54±13 years, 46% (n=31,089) were women, and 64% (n=43,274) were white. After a median follow-up of 5.4 (interquartile range 2.7-8.5) years, a total of 7512 incident strokes occurred (6320 ischemic, 2481 hemorrhagic, and 275 SAH). Overall, there was a graded lower incidence of stroke with higher MET categories. Patients with METs of 12 or more had lower risk of overall stroke [0.42 (95% CI, 0.36-0.49)], ischemic stroke [0.69 (95% CI, 0.58-0.82)], and hemorrhagic stroke [0.71 (95% CI, 0.52-0.95)].

CONCLUSION

In a large ethnically diverse cohort of patients referred for treadmill stress testing, CRF is inversely associated with risk for ischemic and hemorrhagic stroke.

Association of BMI, Fitness, and Mortality in Patients With Diabetes: Evaluating the Obesity Paradox in the Henry Ford Exercise Testing Project (FIT Project) Cohort

OBJECTIVE

To determine the effect of fitness on the association between BMI and mortality among patients with diabetes.

RESEARCH DESIGN AND METHODS

We identified 8,528 patients with diabetes (self-report, medication use, or electronic medical record diagnosis) from the Henry Ford Exercise Testing Project (FIT Project). Patients with a BMI <18.5 kg/m² or cancer were excluded. Fitness was measured as the METs achieved during a physician-referred treadmill stress test and categorized as low (<6), moderate (6-9.9), or high (≥10). Adjusted hazard ratios for mortality were calculated using standard BMI (kilograms per meter squared) cutoffs of normal (18.5-24.9), overweight (25-29.9), and obese (≥30). Adjusted splines centered at 22.5 kg/m² were used to examine BMI as a continuous variable.

RESULTS

Patients had a mean age of 58 ± 11 years (49% women) with 1,319 deaths over a mean follow-up of 10.0 ± 4.1 years. Overall, obese patients had a 30% lower mortality hazard (P < 0.001) compared with normal-weight patients. In adjusted spline modeling, higher BMI as a continuous variable was predominantly associated with a lower mortality risk in the lowest fitness group and among patients with moderate fitness and BMI ≥30 kg/m². Compared with the lowest fitness group, patients with higher fitness had an ∼50% (6-9.9 METs) and 70% (≥10 METs) lower mortality hazard regardless of BMI (P < 0.001).

CONCLUSIONS

Among patients with diabetes, the obesity paradox was less pronounced for patients with the highest fitness level, and these patients also had the lowest risk of mortality.

Implementation of Supervised Exercise Therapy for Patients With Symptomatic Peripheral Artery Disease: A Science Advisory From the American Heart Association

Patients with lower-extremity peripheral artery disease (PAD) have greater functional impairment, faster functional decline, increased rates of mobility loss, and poorer quality of life than people without PAD. Supervised exercise therapy (SET) improves walking ability, overall functional status, and health-related quality of life in patients with symptomatic PAD. In 2017, the Centers for Medicare & Medicaid Services released a National Coverage Determination (CAG-00449N) for SET programs for patients with symptomatic PAD. This advisory provides a practical guide for delivering SET programs to patients with PAD according to Centers for Medicare & Medicaid Services criteria. It summarizes the Centers for Medicare & Medicaid Services process and requirements for referral and coverage of SET and provides guidance on how to implement SET for patients with PAD, including the SET protocol, options for outcome measurement, and transition to home-based exercise. This advisory is based on the guidelines established by the Centers for Medicare & Medicaid Services for Medicare beneficiaries in the United States and is intended to assist clinicians and administrators who are implementing SET programs for patients with PAD.

The Interplay of the Global Atherosclerotic Cardiovascular Disease Risk Scoring and Cardiorespiratory Fitness for the Prediction of All-Cause Mortality and Myocardial Infarction: The Henry Ford ExercIse Testing Project (The FIT Project)

Cardiorespiratory fitness (CRF) is inversely associated with atherosclerotic cardiovascular disease (ASCVD) risk. It is unclear whether the prognostic value of CRF differs by baseline estimated ASCVD risk. We studied a retrospective cohort of patients without known heart failure or myocardial infarction (MI) who underwent treadmill stress testing. CRF was measured by metabolic equivalents of task (METs) and ASCVD risk was calculated using the Pooled Cohorts Equations. Multivariable-adjusted Cox regressions analyses examined the association between METs and incident all-cause mortality and MI outcomes stratified by baseline ASCVD risk. The C-index evaluated risk discrimination while net reclassification improvement evaluated reclassification with CRF added to the ASCVD risk score. Our study population consisted of 57,999 patients of mean age 53 (13) years, 49% women, 64% white, 29% black. Over a median follow-up 11 years (interquartile range 8 to 14 years) there were 6,670 (11%) deaths, while there were 1,757 (3.0%) MIs over a median follow-up of 6 years (interquartile range 3 to 8 years). Among patients with ASCVD risk ≥20%, those with METs ≥12 had a 77% lower risk of all-cause mortality (Hazard ratio 0.23 95% confidence interval = 0.20, 0.27) and 67% lower risk of MI (Hazard ratio 0.33 95% confidence interval = 0.24, 0.46) compared to METs <6. Similar results were obtained for those with ASCVD risk <5%. Addition of METs to ASCVD risk score improved the C-statistic from 0.778 to 0.798 for all-cause mortality and 0.726 to 0.733 for MI (both p <0.001). Addition of METs to ASCVD risk score significantly reclassified risk of all-cause mortality (p <0.001) but not MI (p = 0.052). In conclusion, CRF is inversely associated with risk of all-cause mortality and MI at all levels of ASCVD risk, and provides incremental risk discrimination and reclassification beyond the ASCVD risk score.

Use of Sex-Specific Clinical and Exercise Risk Scores to Identify Patients at Increased Risk for All-Cause Mortality

Importance

Risk assessment tools for exercise treadmill testing may have limited external validity. Cardiovascular mortality has decreased in recent decades, and women have been underrepresented in prior cohorts.

Objectives

To determine whether exercise and clinical variables are associated with differential mortality outcomes in men and women and to assess whether sex-specific risk scores better estimate all-cause mortality.

Design, Setting, and Participants

This retrospective cohort study included 59 877 patients seen at the Cleveland Clinic Foundation (CCF cohort) from January 1, 2000, through December 31, 2010, and 49 278 patients seen at the Henry Ford Hospital (FIT cohort) from January 1, 1991, through December 31, 2009. All patients were 18 years or older and underwent exercise treadmill testing. Data were analyzed from January 1, 2000, to October 27, 2011, in the CCF cohort and from January 1, 1991, to April 1, 2013, in the FIT cohort.

Main Outcomes and Measurements

The CCF cohort was divided randomly into derivation and validation samples, and separate risk scores were developed for men and women. Net reclassification, C statistics, and integrated discrimination improvement were used to compare the sex-specific risk scores with other tools that have all-cause mortality as the outcome. Discrimination and calibration were also evaluated with these sex-specific risk scores in the FIT cohort.

Results

The CCF cohort included 59 877 patients (59.4% men; 40.5% women) with a median (interquartile range [IQR]) age of 54 (45-63) years and 2521 deaths (4.2%) during a median follow-up of 7 (IQR, 4.1-9.6) years. The FIT cohort included 49 278 patients (52.5% men; 47.4% women) with a median (IQR) age of 54 (46-64) years and 6643 deaths (13.5%) during a median (IQR) follow-up of 10.2 (7-13.4) years. C statistics for the sex-specific risk scores in the CCF validation sample were higher (0.79 in women and 0.81 in men) than C statistics using other tools in women (0.70 for Duke Treadmill Score; 0.74 for Lauer nomogram) and men (0.72 for Duke Treadmill Score; 0.75 for Lauer nomogram). Net reclassification and integrated discrimination improvement were superior with the sex-specific risk scores, mostly owing to correct reclassification of events. The sex-specific risk scores in the FIT cohort demonstrated similar discrimination (C statistic, 0.78 for women and 0.79 for men), and calibration was reasonable.

Conclusions and Relevance

Sex-specific risk scores better estimate mortality in patients undergoing exercise treadmill testing. In particular, these sex-specific risk scores help to identify patients at the highest residual risk in the present era.

5-2-1-0 Lifestyle risk factors predict obesity in Millennials

The Making Effective Nutritional Choices Generation Y (MENU GenY) study is a web-based intervention trial aimed at improving food choices in those aged 21-30 years. We report baseline levels of the 5-2-1-0 healthy lifestyle patterns to predict a body mass index (BMI) ≥30 vs <30 kg m^-2 . Overall, 1674 young adults (69% female) from two large health systems enroled and completed an online survey asking questions about lifestyle habits. A multivariable binary logistic regression model was utilized to predict a BMI ≥30 while controlling for known predictors of obesity. Consuming >3 daily servings of fruits/vegetables (odds ratio, OR = 0.90, 95% confidence interval, CI = 0.81, 0.99), and reporting >2.5 hours/week of vigorous physical activity (OR = 0.93, 95% CI = 0.89-0.96, P < 0.001) was associated with a BMI <30. Conversely, time sitting (OR = 1.07, 95% CI = 1.04, 1.11) and consuming sugar-sweetened beverages (OR = 1.08, 95% CI = 1.00, 1.15) were related to a BMI ≥30. In this cohort of 20-30-year-olds, we observed a consistent relationship between obesity and the 5-2-1-0 healthy lifestyle patterns previously reported among children and adolescents.

Cardiorespiratory fitness and incident lung and colorectal cancer in men and women: Results from the Henry Ford Exercise Testing (FIT) cohort

BACKGROUND

To the authors' knowledge, the relationship between cardiorespiratory fitness (CRF) and lung and colorectal cancer outcomes is not well established.

METHODS

A retrospective cohort study was performed of 49,143 consecutive patients who underwent clinician-referred exercise stress testing from 1991 through 2009. The patients ranged in age from 40 to 70 years, were without cancer, and were treated within the Henry Ford Health System in Detroit, Michigan. CRF, measured in metabolic equivalents of task (METs), was categorized as <6 (reference), 6 to 9, 10 to 11, and ≥12. Incident cancer was obtained through linkage to the cancer registry and all-cause mortality from the National Death Index.

RESULTS

Participants had a mean age of 54 ± 8 years. Approximately 46% were female, 64% were white, 29% were black, and 1% were Hispanic. The median follow-up was 7.7 years. Cox proportional hazard models, adjusted for age, race, sex, body mass index, smoking history, and diabetes, found that those in the highest fitness category (METs ≥12) had a 77% decreased risk of lung cancer (hazard ratio [HR], 0.23; 95% CI, 0.14-0.36) and a 61% decreased risk of incident colorectal cancer (HR, 0.39; 95% CI, 0.23-0.66; with additional adjustment for aspirin and statin use). Among those diagnosed with lung and colorectal cancer, those with high fitness had a decreased risk of subsequent death of 44% and 89%, respectively (HR, 0.56 [95% CI, 0.32-1.00] and HR, 0.11 [95% CI, 0.03-0.37], respectively).

CONCLUSIONS

In what to the authors' knowledge is the largest study performed to date, higher CRF was associated with a lower risk of incident lung and colorectal cancer in men and women and a lower risk of all-cause mortality among those diagnosed with lung or colorectal cancer.

Relation of Isolated Low High-Density Lipoprotein Cholesterol to Mortality and Cardiorespiratory Fitness (from the Henry Ford Exercise Testing Project [FIT Project])

Isolated low high-density lipoprotein cholesterol (HDL-C) is associated with lower fitness and increased mortality. Whether the association between isolated low HDL-C and mortality differs by fitness is uncertain. Patients in the Henry Ford ExercIse Testing Project (FIT Project) completed a physician-referred treadmill stress test and those prescribed lipid-lowering medications or with known cardiovascular disease were excluded. Isolated low HDL-C was defined as HDL-C <40 mg/dl for men and <50 mg/dl for women with low-density lipoprotein cholesterol (LDL-C) and triglycerides <100 mg/dl (n = 688). An optimal lipid panel was defined as HDL-C ≥40 mg/dl for men and ≥50 mg/dl for women with LDL-C and triglycerides <100 mg/dl (n = 2,923). Mortality was ascertained through Social Security Death Index linkage. Patients with isolated low HDL-C had a mean age of 48.9 ± 12.9 years and 62.9% were women. Over a mean follow-up of 10.3 ± 5 years, 12.8% of patients with isolated low HDL-C and 8.7% with optimal lipids died. Compared to individuals with optimal lipids, those with isolated low HDL-C who achieved <6 METs had a lower survival (p = 0.02), whereas there was no mortality difference for those who achieved 6 to 10 METs (p = 0.13) or ≥10 METs (p = 0.66). In adjusted Cox models, the mortality hazard for those with isolated low HDL-C compared with optimal lipids was 1.73 (95% confidence interval [CI] 1.18 to 2.54), 1.90 (95% CI 1.19 to 3.04), and 0.97 (95% CI 0.53 to 1.78) for the METS categories of <6, 6 to 10, and ≥10. In conclusion, individuals with isolated low HDL-C fitness significantly improved risk stratification and only those with lower fitness had an increased totality mortality risk.

Higher cardiorespiratory fitness predicts long-term survival in patients with heart failure and preserved ejection fraction: the Henry Ford Exercise Testing (FIT) Project

INTRODUCTION

Higher cardiorespiratory fitness (CRF) is associated with improved exercise capacity and quality of life in heart failure with preserved ejection fraction (HFpEF), but there are no large studies evaluating the association of HFpEF, CRF, and long-term survival. We therefore aimed to determine the association between CRF and all-cause mortality, in patients with HFpEF.

MATERIAL AND METHODS

In the Henry Ford Exercise Testing (FIT) Project, 167 patients had baseline HFpEF, defined as a clinical diagnosis of heart failure with ejection fraction ≥ 50% on echocardiogram. The CRF was estimated from the peak workload (in METs) from a clinician-referred treadmill stress test and categorized as poor (1-4 METs), intermediate (5-6 METs), and moderate-high (≥ 7 METs). Additional analyses assessing the effect of HFpEF and CRF on mortality were also conducted, matching HFpEF patients to non-HFpEF patients using propensity scores.

RESULTS

Mean age was 64 ±13 years, with 55% women, and 46% Black. Over a median follow-up of 9.7 (5.2-18.9) years, there were 103 deaths. In fully adjusted models, moderate-high CRF was associated with 63% lower mortality risk (HR = 0.37, 95% CI: 0.18-0.73) compared to the poor-CRF group. In the propensity-matched cohort, HFpEF was associated with a HR of 2.3 (95% CI: 1.7-3.2) for mortality compared to non-HFpEF patients, which was attenuated to 1.8 (95% CI: 1.3-2.5) after adjusting for CRF.

CONCLUSIONS

Moderate-high CRF in patients with HFpEF is associated with improved survival, and differences in CRF partly explain the intrinsic risk of HFpEF. Randomized trials of interventions aimed at improving CRF in HFpEF are needed.

Exercise Oscillatory Ventilation: Interreviewer Agreement and a Novel Determination

INTRODUCTION

Determination of exercise oscillatory ventilation (EOV) is subjective, and the interreviewer agreement has not been reported. The purposes of this study were, among patients with heart failure (HF), as follows: 1) to determine the interreviewer agreement for EOV and 2) to describe a novel, objective, and quantifiable measure of EOV.

METHODS

This was a secondary analysis of the HEART Camp: Promoting Adherence to Exercise in Patients with Heart Failure study. EOV was determined through a blinded review by six individuals on the basis of their interpretation of the EOV literature. Interreviewer agreement was assessed using Fleiss kappa (κ). Final determination of EOV was based on agreement by four of the six reviewers. A new measure (ventilation dispersion index; VDI) was calculated for each test, and its ability to predict EOV was assessed with the receiver operator characteristics curve.

RESULTS

Among 243 patients with HF (age, 60 ± 12 yr; 45% women), the interreviewer agreement for EOV was fair (κ = 0.303) with 10-s discrete data averages and significantly better, but only moderate (κ = 0.429) with 30-s rolling data averages. Prevalence rates of positive and indeterminate EOVs were 18% and 30% with the 10-s discrete averages and 14% and 13% with the 30-s rolling averages, respectively. VDI was strongly associated with EOV, with areas under the receiver operator characteristics curve of 0.852 to 0.890.

CONCLUSIONS

Interreviewer agreement for EOV in patients with HF is fair to moderate, which can negatively affect risk stratification. VDI has strong predictive validity with EOV; as such, it might be a useful measure of prognosis in patients with HF.

Inverse association of pulse pressure augmentation during exercise with heart failure and death

OBJECTIVE

Resting pulse pressure (PP) is a risk factor for heart failure (HF); however, whether PP augmentation during exercise, a parameter easily obtained from routine treadmill stress testing, is associated with incident HF is unknown. Thus, we aimed to study the relationship between a novel parameter, the pulse pressure stress index (P2SI), and adverse outcomes among adults undergoing clinical exercise stress testing in the Henry Ford Exercise Testing Project.

METHODS

The P2SI was calculated as PP at peak exercise divided by resting PP and was analysed continuously and categorically using quartiles. Cox models examined the association between P2SI and adjusted HR (aHR) of incident HF, myocardial infarction (MI) or death. Receiver operating curve (ROC) analyses tested the optimal prognostic cut-point for P2SI.

RESULTS

Among 55 524 participants without prior MI or HF, mean (SD) age was 53 (13) years, 51% were men and 29% black. A total of 2516 HF, 1606 MI and 6224 mortality outcomes occurred. Quartile 3 P2SI (2.0-2.4) was chosen as the reference category based on ROC analyses. There was a graded inverse association of low P2SI with excess HF (aHR of 1.3 (95% CI 1.1 to 1.5) for quartile 2 and 1.5 (95% CI 1.2 to 1.8) for quartile 1, p for trend<0.001) and mortality (aHR of 1.1 (95% CI 1.01 to 1.2) for quartile 2 and 1.3 (95% CI 1.2 to 1.5) for quartile 1, p for trend<0.001). There was no association between P2SI and MI after adjustment. P2SI added significant prognostic information to more established stress testing parameters such as peak systolic blood pressure, per cent maximal predicted heart rate achieved and metabolic equivalents of task achieved.

CONCLUSIONS

Poor augmentation of PP with exercise, specifically a P2SI below 2, is a novel and readily quantifiable exercise-based risk feature for HF and death.

Exercise training workloads in cardiac rehabilitation are associated with clinical outcomes in patients with heart failure

BACKGROUND

In patients with coronary heart disease, the exercise workload (i.e., metabolic equivalents of task, METs) at which patients exercise train upon entry and completion of cardiac rehabilitation (CR) are independently related to prognosis. Unknown is the association between exercise training workloads in CR and clinical outcomes in patients with heart failure (HF).

METHODS

Patients with HF who participated in an early outpatient CR program were used in this retrospective analysis. Exercise workloads upon entry and completion of CR were converted to METs. The primary outcome was all-cause mortality and the secondary outcome was HF hospitalization. Cox regression analysis was used to assess the adjusted risk between MET levels in CR and clinical outcomes.

RESULTS

Among 707 patients, the median exercise training workload at the start and end of CR was 2.5 METs (IQR 2.1 to 3.1 METs) and 3.2 METS (IQR 2.7 to 4.1 METs), respectively, for men and 2.2 METs (IQR 1.9 to 2.6 METs) and 2.9 METS (IQR 2.3 to 3.4 METs), respectively, for women. There were 242 deaths and 266 HF hospitalizations. METs achieved at the end of CR had the strongest independent association with all-cause mortality (adjusted HR, 95% CI: 0.58, 0.48-0.70) and HF hospitalization (adjusted HR, 95% CI: 0.62, 0.52-0.74). Each 1 MET higher work load at the end of CR was associated with a 42% and 38% lower adjusted risk for all-cause mortality and HF hospitalization, respectively.

CONCLUSIONS

In a diverse cohort of patients with chronic HF our data suggests that an easily accessible measure of exercise capacity (i.e., METs) that is collected during CR is independently associated with the adjusted risk for both all-cause mortality and HF-specific hospitalization. Training at MET levels <3.5 METs identifies patients that might benefit from closer clinical surveillance and reinforced adherence to medical and lifestyle preventive strategies.

Exercise Capacity and the Obesity Paradox in Heart Failure: The FIT (Henry Ford Exercise Testing) Project

OBJECTIVES

To assess the influence of exercise capacity and body mass index (BMI) on 10-year mortality in patients with heart failure (HF) and to synthesize these results with those of previous studies.

PATIENTS AND METHODS

This large biracial sample included 774 men and women (mean age, 60±13 years; 372 [48%] black) with a baseline diagnosis of HF from the Henry Ford Exercise Testing (FIT) Project. All patients completed a symptom-limited maximal treadmill stress test from January 1, 1991, through May 31, 2009. Patients were grouped by World Health Organization BMI categories for Kaplan-Meier survival analyses and stratified by exercise capacity (<4 and ≥4 metabolic equivalents [METs] of task). Associations of BMI and exercise capacity with all-cause mortality were assessed using multivariable-adjusted Cox proportional hazards models.

RESULTS

During a mean follow-up of 10.1±4.6 years, 380 patients (49%) died. Kaplan-Meier survival plots revealed a significant positive association between BMI category and survival for exercise capacity less than 4 METs (log-rank, P=.05), but not greater than or equal to 4 METs (P=.76). In the multivariable-adjusted models, exercise capacity (per 1 MET) was inversely associated, but BMI was not associated, with all-cause mortality (hazard ratio, 0.89; 95% CI, 0.85-0.94; P<.001 and hazard ratio, 0.99; 95% CI, 0.97-1.01; P=.16, respectively).

CONCLUSION

Maximal exercise capacity modified the relationship between BMI and long-term survival in patients with HF, upholding the presence of an exercise capacity-obesity paradox dichotomy as observed over the short-term in previous studies.

Prognostic value of exercise capacity among patients with treated depression: The Henry Ford Exercise Testing (FIT) Project

BACKGROUND

Exercise capacity is associated with survival in the general population. Whether this applies to patients with treated depression is not clear.

HYPOTHESIS

High exercise capacity remains associated with lower risk of all-cause mortality (ACM) and nonfatal myocardial infraction (MI) among patients with treated depression.

METHODS

We included 5128 patients on antidepressant medications who completed a clinically indicated exercise stress test between 1991 and 2009. Patients were followed for a median duration of 9.4 years for ACM and 4.5 years for MI. Exercise capacity was estimated in metabolic equivalents of tasks (METs). Cox proportional hazards regression models were used.

RESULTS

Patients with treated depression who achieved ≥12 METs (vs those achieving <6 METs) were younger (age 46 ± 9 vs 61 ± 12 years), more often male (60% vs 23%), less often black (10% vs 27%), and less likely to be hypertensive (51% vs 86%), have DM (9% vs 38%), or be obese (11% vs 36%) or dyslipidemic (45% vs 54%). In the fully adjusted Cox proportional hazard regression model, exercise capacity was associated with a lower ACM (HR per 1-MET increase in exercise capacity: 0.82, 95% CI: 0.79-0.85, P < 0.001) and nonfatal MI (HR: 0.92, 95% CI: 0.87-0.97, P = 0.004).

CONCLUSIONS

Exercise capacity had an inverse association with both ACM and nonfatal MI in patients with treated depression, independent of cardiovascular risk factors. These results highlight the potential impact of assessing exercise capacity to identify risk, as well as promoting an active lifestyle among treated depression patients.

Cardiopulmonary Exercise Measures of Men and Women with HFrEF Differ in Their Relationship to Prognosis: The Henry Ford Hospital Cardiopulmonary Exercise Testing (FIT-CPX) Project

BACKGROUND

This study evaluated if different prognostic characteristics exist for peak oxygen consumption (VO₂), percent predicted peak VO₂ (ppVO₂), and the slope of the change in minute ventilation to volume of carbon dioxide produced (V_E-VCO₂) slope between men and women with heart failure and reduced ejection fraction (HFrEF).

METHODS

Analysis of the Henry Ford Hospital Cardiopulmonary Exercise Testing database (n = 1085; 33% women, 55% black) of individuals with HFrEF who completed a physician-referred cardiopulmonary exercise testing (CPX) between 1997 and 2010. Primary outcome was a composite of all-cause death, left ventricular assist device placement, and orthotopic heart transplant . Logistic and Cox regressions were performed and Kaplan-Meier survival curves were developed to describe relationships of the CPX variables and the composite outcome within and between men and women.

RESULTS

All patients were followed-up for a minimum of 5 years, during which there were 643 combined events (62%; 499 deaths, 64 left ventricular assist device implants, 80 orthotopic heart transplant). Each CPX variable was significantly related to event-free survival among both men and women. Log-rank assessment of Kaplan-Meier curves noted survival differences for peak VO₂ and V_E-VCO₂ slope (p ≤ .002), but not ppVO₂ (P = .32), between men and women.

CONCLUSIONS

Prognostic values for peak VO₂ and the V_E-VCO₂ slope might be considered separately for men and women, whereas the ppVO₂ value corresponding to 1- and 3-year survival rates may not be different between the sexes.

Using Machine Learning to Define the Association between Cardiorespiratory Fitness and All-Cause Mortality (from the Henry Ford Exercise Testing Project)

Previous studies have demonstrated that cardiorespiratory fitness is a strong marker of cardiovascular health. Machine learning (ML) can enhance the prediction of outcomes through classification techniques that classify the data into predetermined categories. The aim of the analysis is to compare the prediction of 10 years of all-cause mortality (ACM) using statistical logistic regression (LR) and ML approaches in a cohort of patients who underwent exercise stress testing. We included 34,212 patients (55% males, mean age 54 ± 13 years) free of coronary artery disease or heart failure who underwent exercise treadmill stress testing between 1991 and 2009 and had complete 10-year follow-up. The primary outcome of this analysis was ACM at 10 years. The probability of 10-years ACM was calculated using statistical LR and ML, and the accuracy of these methods was calculated and compared. A total of 3,921 patients died at 10 years. Using statistical LR, the sensitivity to predict ACM was 44.9% (95% confidence interval [CI] 43.3% to 46.5%), whereas the specificity was 93.4% (95% CI 93.1% to 93.7%). The sensitivity of ML to predict ACM was 87.4% (95% CI 86.3% to 88.4%), whereas the specificity was 97.2% (95% CI 97.0% to 97.4%). The ML approach was associated with improved model discrimination (area under the curve for ML [0.923 (95% CI 0.917 to 0.928)]) compared with statistical LR (0.836 [95% CI 0.829 to 0.846], p<0.0001). In conclusion, our analysis demonstrates that ML provides better accuracy and discrimination of the prediction of ACM among patients undergoing stress testing.

Relation of Exercise Capacity to Risk of Development of Diabetes in Patients on Statin Therapy (the Henry Ford Exercise Testing Project)

High exercise capacity (EC) has been associated with a lower risk of incident diabetes, whereas statin therapy has been associated with a higher risk. We sought to investigate whether the association between EC and diabetes risk is modified by statin therapy. This retrospective cohort study included 47,337 patients without diabetes or coronary artery disease at baseline (age 53 ± 13 years, 48% women, 66% white) who underwent clinical treadmill stress testing within the Henry Ford Health System from January 1, 1991, to May 31, 2009. The patients were stratified by baseline statin use and estimated peak METs achieved during exercise testing. Hazard ratios for incident diabetes were calculated using Cox proportional hazards models adjusted for demographic characteristics, co-morbidities, pertinent medications, and stress test indication. We observed 6,921 new diabetes cases (14.6%) over a median follow-up period of 5.1 years (interquartile interval of 2.6 to 8.2 years). Compared with the statin group, the no-statin group achieved higher mean METs (8.9 ± 2.7 vs 9.6 ± 3.0, respectively; p <0.001). After adjustment for covariates, a higher EC was associated with a lower risk of incident diabetes, irrespective of statin use (p-interaction = 0.15). Each 1-MET increment was associated with an 8%, 8%, and 6% relative risk reduction in the total cohort, the no-statin, and the statin groups, respectively (95% confidence interval, 0.91 to 0.93, 0.91 to 0.93, and 0.91 to 0.96, respectively; p <0.001 for all). We conclude that a higher EC is associated with a lower risk of incident diabetes regardless of statin use.

Prognostic value of exercise capacity among men undergoing pharmacologic treatment for erectile dysfunction: The FIT Project

BACKGROUND

Vascular erectile dysfunction (ED) has been identified as a potentially useful risk factor for predicting future cardiovascular events, particularly in younger men. Because these men typically score more favorably on traditional cardiovascular disease risk assessment tools, there exists a gap in knowledge for how to most appropriately identify those men who would benefit from more aggressive treatments. To date, no studies have examined the impact of fitness on cardiovascular outcomes in men with ED. This study sought to examine the prognostic impact of maximal exercise capacity on cardiovascular-related outcomes in men ages 40 to 60 years being treated for ED.

HYPOTHESIS

We hypothesized that there would be an independent association between higher baseline fitness level and lower cardiovascular events.

METHODS

We analyzed 1152 men with pharmacy claims file-confirmed active pharmacologic treatment for ED from the Henry Ford Exercise Testing (FIT) Project (1991-2009). All patients were free of coronary heart disease and heart failure, and underwent clinician-referred exercise stress testing, with fitness measured in metabolic equivalents of task (METs). Multivariable Cox proportional hazard models adjusted for traditional cardiovascular risk factors were used to study the association between fitness and all-cause mortality, major adverse cardiovascular events (MACE) (defined as myocardial infarction or revascularization), and incident type 2 diabetes mellitus.

RESULTS

The mean age of the population was 53 years, with 39% African Americans. In multivariable analysis, each 1 MET of fitness was associated with a 16% lower risk of death (hazard ratio [HR]: 0.84, 95% confidence interval [CI]: 0.76-0.94, P = 0.002), and a nonsignificant reduction in MACE (HR: 0.89, 95% CI: 0.79-1.003, P = 0.048), and incident diabetes (HR: 0.92, 95% CI: 0.85-1.01, P = 0.129).

CONCLUSIONS

Higher baseline fitness is associated with improved cardiovascular prognosis in a population of middle-aged men treated for ED.

Cardiorespiratory fitness and incident heart failure: The Henry Ford ExercIse Testing (FIT) Project

BACKGROUND

Prior studies have demonstrated cardiorespiratory fitness (CRF) to be a strong marker of cardiovascular health. However, there are limited data investigating the association between CRF and risk of progression to heart failure (HF). The purpose of this study was to determine the relationship between CRF and incident HF.

METHODS

We included 66,329 patients (53.8% men, mean age 55 years) free of HF who underwent exercise treadmill stress testing at Henry Ford Health Systems between 1991 and 2009. Incident HF was determined using International Classification of Diseases, Ninth Revision codes from electronic medical records or administrative claim files. Cox proportional hazards models were performed to determine the association between CRF and incident HF.

RESULTS

A total of 4,652 patients developed HF after a median follow-up duration of 6.8 (±3) years. Patients with incident HF were older (63 vs 54 years, P<.001) and had higher prevalence of known coronary artery disease (42.3% vs 11%, P<.001). Peak metabolic equivalents (METs) of task were 6.3 (±2.9) and 9.1 (±3) in the HF and non-HF groups, respectively. After adjustment for potential confounders, patients able to achieve ≥12 METs had an 81% lower risk of incident HF compared with those achieving <6 METs (hazard ratio 0.19 [95% CI 0.14-0.29], P for trend < .001). Each 1 MET achieved was associated with a 16% lower risk (hazard ratio 0.84 [95% CI 0.82-0.86], P<.001) of incident HF.

CONCLUSIONS

Our analysis demonstrates that higher level of fitness is associated with a lower incidence of HF independent of HF risk factors.

Higher Fitness Is Strongly Protective in Patients with Family History of Heart Disease: The FIT Project

BACKGROUND

Cardiorespiratory fitness protects against mortality; however, little is known about the benefits of improved fitness in individuals with a family history of coronary heart disease. We studied the association between cardiorespiratory fitness and risk of incident coronary heart disease and all-cause mortality, hypothesizing an inverse relationship similar to individuals without a family history of coronary heart disease.

METHODS

We included 57,999 patients (aged 53 ± 13 years; 49% were female; 29% were black) from the Henry Ford Exercise Testing (FIT) Project. Cardiorespiratory fitness was expressed in metabolic equivalents of task based on exercise stress testing. Family history was determined as self-reported coronary heart disease in a first-degree relative at any age. We used Cox proportional hazards models adjusted for demographics and cardiovascular disease risk factors to examine the association between cardiorespiratory fitness and risk of incident coronary heart disease and mortality over a median (interquartile range) follow-up of 5.5 (5.6) and 10.4 (6.8) years, respectively.

RESULTS

Overall, 51% reported a positive family history. Each 1-unit metabolic equivalent increase was associated with lower incident coronary heart disease and mortality risk regardless of family history status. The hazard ratio and 95% confidence interval for a negative family history and a positive family history were 0.87 (0.84-0.89) and 0.87 (0.85-0.89) for incident coronary heart disease and 0.83 (0.82-0.84) and 0.83 (0.82-0.85) for mortality, respectively. There was no significant interaction between family history and categoric cardiorespiratory fitness, sex, or age (P >.05 for all).

CONCLUSIONS

Higher cardiorespiratory fitness is strongly protective in all patients regardless of family history status, supporting recommendations for regular exercise in those with a family history.

Change in Maximal Exercise Capacity Is Associated With Survival in Men and Women

OBJECTIVE

To describe the relationship between change in maximal exercise capacity (MEC) over time and risk of all-cause mortality separately in men and women.

PATIENTS AND METHODS

Consecutive patients (n=10,854; mean ± SD age, 54±11 years; 43% women; 30% nonwhite) who completed 2 physician-referred exercise tests between January 2, 1991, and May 28, 2009, were identified from the Henry Ford Exercise Testing (FIT) Project. The MEC was quantified in metabolic equivalents of task (METs) calculated from peak workload on a treadmill and adjusted to the equivalent for a 50-year-old man. Multivariable Cox proportional hazards regression was performed to assess risk of all-cause mortality associated with change in MEC based on (1) change from age-/sex-adjusted low fitness (<8 METs) to intermediate or high fitness and (2) an absolute change in METs.

RESULTS

Relative to patients with low fitness at both tests, increasing from low to intermediate or high fitness was associated with lower risk of all-cause mortality (adjusted hazard ratio [aHR] = 0.63 [95% CI, 0.45-0.87] in men and 0.56 [95% CI, 0.34-0.91] in women). Each 1-MET increase in age-/sex-adjusted MEC between baseline and follow-up was associated with an aHR of 0.87 (95% CI, 0.84-0.91) in men and 0.84 (95% CI, 0.79-0.89) in women, with no significant interaction by sex (P=.995). Similar aHRs were observed in a subgroup with intermediate fitness at baseline.

CONCLUSION

In men and women referred for an exercise stress test, change in MEC over time is inversely related to risk of all-cause mortality.

Chronotropic Incompetence and Risk of Atrial Fibrillation: The Henry Ford ExercIse Testing (FIT) Project

OBJECTIVES

To examine the association between chronotropic incompetence and incident atrial fibrillation (AF).

BACKGROUND

Patients with inadequate heart rate response during exercise may have abnormalities in sinus node function or autonomic tone that predispose to the development of AF.

METHODS

We examined the association between heart rate response and incident AF in 57,402 (mean age=54±13 years, 47% female, 64% white) patients free of baseline AF who underwent exercise-treadmill stress testing from the Henry Ford ExercIse Testing (FIT) Project. Age-predicted maximum heart rate (pMHR) values <85% and chronotropic index values <80% were used to define chronotropic incompetence. Cox regression, adjusting for demographics, cardiovascular risk factors, medications, coronary heart disease, heart failure, and metabolic equivalent of task achieved, was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between chronotropic incompetence and incident AF.

RESULTS

Over a median follow-up of 5.0 years (25^th-75^th percentiles=2.6, 7.8), a total of 3,395 (5.9%) participants developed AF. pMHR values <85% were associated with an increased risk for AF development (HR=1.33, 95%CI=1.22, 1.44). Chronotropic index values <80% also were associated with an increased risk of AF (HR=1.28, 95%CI=1.19, 1.38). The associations of pMHR and chronotropic index with AF remained significant with varying cut-off points to define chronotropic incompetence.

CONCLUSIONS

Our analysis suggests that patients with inadequate heart rate response during exercise have an increased risk for developing AF.

Variables Measured During Cardiopulmonary Exercise Testing as Predictors of Mortality in Chronic Systolic Heart Failure

BACKGROUND

Data from a cardiopulmonary exercise (CPX) test are used to determine prognosis in patients with chronic heart failure (HF). However, few published studies have simultaneously compared the relative prognostic strength of multiple CPX variables.

OBJECTIVES

The study sought to describe the strength of the association among variables measured during a CPX test and all-cause mortality in patients with HF with reduced ejection fraction (HFrEF), including the influence of sex and patient effort, as measured by respiratory exchange ratio (RER).

METHODS

Among patients (n = 2,100, 29% women) enrolled in the HF-ACTION (HF-A Controlled Trial Investigating Outcomes of exercise traiNing) trial, 10 CPX test variables measured at baseline (e.g., peak oxygen uptake [Vo2], exercise duration, percent predicted peak Vo2 [%ppVo2], ventilatory efficiency) were examined.

RESULTS

Over a median follow-up of 32 months, there were 357 deaths. All CPX variables, except RER, were related to all-cause mortality (all p < 0.0001). Both %ppVo2 and exercise duration were equally able to predict (Wald chi-square: ∼141) and discriminate (c-index: 0.69) mortality. Peak Vo2 (ml·kg(-1)·min(-1)) was the strongest predictor of mortality among men (Wald chi-square: 129) and exercise duration among women (Wald chi-square: 41). Multivariable analyses showed that %ppVo2, exercise duration, and peak Vo2 (ml·kg(-1)·min(-1)) were similarly able to predict and discriminate mortality. In men, a 10% 1-year mortality rate corresponded to a peak Vo2 of 10.9 ml·kg(-1)·min(-1) versus 5.3 ml·kg(-1)·min(-1) in women.

CONCLUSIONS

Peak Vo2, exercise duration, and % ppVo2 carried the strongest ability to predict and discriminate the likelihood of death in patients with HFrEF. The prognosis associated with a given peak Vo2 differed by sex. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437).

Sex Differences in Cardiorespiratory Fitness and All-Cause Mortality: The Henry Ford ExercIse Testing (FIT) Project

OBJECTIVE

To determine whether sex modifies the relationship between fitness and mortality.

PATIENTS AND METHODS

We included 57,284 patients without coronary artery disease or heart failure who completed a routine treadmill exercise test between 1991 and 2009. We determined metabolic equivalent tasks (METs) and linked patient records with mortality data via the Social Security Death Index. Multivariable Cox regression was used to determine the association between sex, fitness, and all-cause mortality.

RESULTS

There were 29,470 men (51.4%) and 27,814 women (48.6%) with mean ages of 53 and 54 years, respectively. Overall, men achieved 1.7 METs higher than women (P<.001). During median follow-up of 10 years, there were 6402 deaths. The mortality rate for men in each MET group was similar to that for women, who achieved an average of 2.6 METs lower (P=.004). Fitness was inversely associated with mortality in both men (hazard ratio [HR], 0.84 per 1 MET; 95% CI, 0.83-0.85) and women (HR, 0.83 per 1 MET; 95% CI, 0.81-0.84). This relationship did not plateau at high or low MET values.

CONCLUSION

Although men demonstrated 1.7 METs higher than women, their survival was equivalent to that of women demonstrating 2.6 METs lower. Furthermore, higher MET values were associated with lower mortality for both men and women across the range of MET values. These findings are useful for tailoring prognostic information and lifestyle guidance to men and women undergoing stress testing.

Relationship Between Exercise Workload During Cardiac Rehabilitation and Outcomes in Patients With Coronary Heart Disease

The purpose of this retrospective, observational study was to describe the relation between exercise workload during cardiac rehabilitation (CR), expressed as metabolic equivalents of task (METs), and prognosis among patients with coronary heart disease. We included patients with coronary heart disease who participated in CR between January 1998 and June 2007. METs were calculated from treadmill workload. Cox regression analysis was used to describe the relationship between METs and time to a composite outcome of all-cause mortality, nonfatal myocardial infarction, or heart failure hospitalization. Among 1,726 patients (36% women; median age 59 years [interquartile range, 52 to 66]), there were 467 events (27%) during a median follow-up of 5.8 years (interquartile range, 2.6 to 8.7). In analyses adjusted for age, sex, Charlson co-morbidity index, hypertension, diabetes, and CR referral diagnosis, METs were independently related to the composite outcome at CR start (Wald chi-square 43, hazard ratio 0.59 [95% confidence interval 0.51 to 0.70]) and CR end (Wald chi-square 47, hazard ratio 0.68 [95% confidence interval 0.61 to 0.76]). Patients exercising below 3.5 METs on exit from CR represent a high-risk group with 1- and 3-year event rates ≥7% and ≥18%, respectively. In conclusion, METs during CR is available at no additional cost and can be used to identify patients at increased risk for an event who may benefit from closer follow-up, extended length of stay in CR, and/or participation in other strategies aimed at maximizing adherence to secondary preventive behaviors and improving exercise capacity.

Prognostic value of cardiopulmonary exercise testing in heart failure with preserved ejection fraction. The Henry Ford HospITal CardioPulmonary EXercise Testing (FIT-CPX) project

BACKGROUND

Although cardiopulmonary exercise (CPX) testing in patients with heart failure and reduced ejection fraction is well established, there are limited data on the value of CPX variables in patients with HF and preserved ejection fraction (HFpEF). We sought to determine the prognostic value of select CPX measures in patients with HFpEF.

METHODS

This was a retrospective analysis of patients with HFpEF (ejection fraction ≥ 50%) who performed a CPX test between 1997 and 2010. Selected CPX variables included peak oxygen uptake (VO2), percent predicted maximum oxygen uptake (ppMVO2), minute ventilation to carbon dioxide production slope (VE/VCO2 slope) and exercise oscillatory ventilation (EOV). Separate Cox regression analyses were performed to assess the relationship between each CPX variable and a composite outcome of all-cause mortality or cardiac transplant.

RESULTS

We identified 173 HFpEF patients (45% women, 58% non-white, age 54 ± 14 years) with complete CPX data. During a median follow-up of 5.2 years, there were 42 deaths and 5 cardiac transplants. The 1-, 3-, and 5-year cumulative event-free survival was 96%, 90%, and 82%, respectively. Based on the Wald statistic from the Cox regression analyses adjusted for age, sex, and β-blockade therapy, ppMVO2 was the strongest predictor of the end point (Wald χ(2) = 15.0, hazard ratio per 10%, P < .001), followed by peak VO2 (Wald χ(2) = 11.8, P = .001). VE/VCO2 slope (Wald χ(2)= 0.4, P = .54) and EOV (Wald χ(2) = 0.15, P = .70) had no significant association to the composite outcome.

CONCLUSION

These data support the prognostic utility of peak VO2 and ppMVO2 in patients with HFpEF. Additional studies are needed to define optimal cut points to identify low- and high-risk patients.

Exercise Parameters and Risk of Coronary Artery Disease and Mortality Among Patients Who Use Pulmonary Medications: The FIT Project

BACKGROUND

In the general population, the exercise treadmill testing variables of lower resting heart rate, higher peak heart rate, and greater fitness have favorable prognosis for mortality. Patients with obstructive lung disease have increased mortality risk. Furthermore, some pulmonary medications (ie, beta2-agonists) can influence heart rate. We determined whether exercise treadmill test parameters carry the same prognostic value in patients who are using versus not using pulmonary medications.

METHODS

We analyzed data on 69,855 patients (mean age, 55 years) who completed a clinically indicated exercise treadmill test. Patients were defined as having "lung disease" if they were taking medications routinely used to treat obstructive lung disease (n = 6145, 9%). International Classification of Diseases, 9th Revision codes regarding the type of lung disease were not available. Multivariate-adjusted Cox models were used to determine the risk of mortality, major adverse cardiac events, and myocardial infarction over a mean of 11 years follow-up.

RESULTS

Higher resting heart rate was associated with increased mortality risk, and higher peak heart rate and fitness were associated with decreased risk. No significant interaction for lung disease status was seen for the heart rate variables, but a slightly stronger protective effect was observed for higher fitness among patients with lung disease (P interaction = .032). The results were similar for major adverse cardiac events and myocardial infarction.

CONCLUSIONS

Heart rate parameters achieved on exercise treadmill tests are equally prognostic among patients using versus not using pulmonary medications. Higher fitness was associated with improved clinical outcomes for both; however, the relative benefit of fitness on survival was even greater in patients using pulmonary medications compared with those not using them.

High Exercise Capacity Attenuates the Risk of Early Mortality After a First Myocardial Infarction: The Henry Ford Exercise Testing (FIT) Project

OBJECTIVE

To examine the effect of objectively measured exercise capacity (EC) on early mortality (EM) after a first myocardial infarction (MI).

PATIENTS AND METHODS

This retrospective cohort study included 2061 patients without a history of MI (mean age, 62±12 years; 38% [n=790] women; 56% [n=1153] white) who underwent clinical treadmill stress testing in the Henry Ford Health System from January 1, 1991, through May 31, 2009, and suffered MI during follow-up (MI event proportion, 3.4%; mean time from the exercise test to MI, 6.1±4.3 years). Exercise capacity was categorized on the basis of peak metabolic equivalents (METs) achieved: less than 6, 6 to 9, 10 to 11, and 12 or more METs. Early mortality was defined as all-cause mortality within 28, 90, or 365 days of MI. Multivariable logistic regression models were used to assess the effect of EC on the risk of mortality at each time point post-MI adjusting for baseline demographic characteristics, cardiovascular risk factors, medication use, indication for stress testing, and year of MI.

RESULTS

The 28-day EM rate was 10.6% overall, and 13.9%, 10.7%, 6.9%, and 6.0% in the less than 6, 6 to 9, 10 to 11, and 12 or more METs categories, respectively (P<.001). Patients who died were more likely to be older, be less fit, be nonobese, have treated hypertension, and have a longer duration from baseline to incident MI (P<.05). Adjusted regression analyses revealed a decreased risk of EM with increasing EC categories. A 1-MET higher EC was associated with an 8% to 10% lower risk of mortality across all time points (28 days: odds ratio [OR], 0.92; 95% CI, 0.87-0.98; P=.006; 90 days: OR, 0.90; 95% CI, 0.86-0.95; P<.001; 365 days: OR, 0.91; 95% CI, 0.87-0.94; P<.001).

CONCLUSION

Higher baseline EC was independently associated with a lower risk of early death after a first MI.

Relation of Risk of Atrial Fibrillation With Systolic Blood Pressure Response During Exercise Stress Testing (from the Henry Ford ExercIse Testing Project)

Decreases in systolic blood pressure during exercise may predispose to arrhythmias such as atrial fibrillation (AF) because of underlying abnormal autonomic tone. We examined the association between systolic blood pressure response and incident AF in 57,442 (mean age 54 ± 13 years, 47% women, and 29% black) patients free of baseline AF who underwent exercise treadmill stress testing from the Henry Ford ExercIse Testing project. Exercise systolic blood pressure response was examined as a categorical variable across clinically relevant categories (>20 mm Hg: referent; 1 to 20 mm Hg, and ≤0 mm Hg) and per 1-SD decrease. Cox regression, adjusting for demographics, cardiovascular risk factors, medications, history of coronary heart disease, history of heart failure, and metabolic equivalent of task achieved, was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between systolic blood pressure response and incident AF. Over a median follow-up of 5.0 years, a total of 3,381 cases (5.9%) of AF were identified. An increased risk of AF was observed with decreasing systolic blood pressure response (>20 mm Hg: HR 1.0, referent; 1 to 20 mm Hg: HR 1.09, 95% CI 0.99, 1.20; ≤0 mm Hg: HR 1.22, 95% CI 1.06 to 1.40). Similar results were obtained per 1-SD decrease in systolic blood pressure response (HR 1.08, 95% CI 1.04 to 1.12). The results were consistent when stratified by age, sex, race, hypertension, and coronary heart disease. In conclusion, our results suggest that a decreased systolic blood pressure response during exercise may identify subjects who are at risk for developing AF.

Cardiorespiratory fitness and incident diabetes: the FIT (Henry Ford ExercIse Testing) project

OBJECTIVE

Prior evidence has linked higher cardiorespiratory fitness with a lower risk of diabetes in ambulatory populations. Using a demographically diverse study sample, we examined the association of fitness with incident diabetes in 46,979 patients from The Henry Ford ExercIse Testing (FIT) Project without diabetes at baseline.

RESEARCH DESIGN AND METHODS

Fitness was measured during a clinician-referred treadmill stress test performed between 1991 and 2009. Incident diabetes was defined as a new diagnosis of diabetes on three separate consecutive encounters derived from electronic medical records or administrative claims files. Analyses were performed with Cox proportional hazards models and were adjusted for diabetes risk factors.

RESULTS

The mean age was 53 years with 48% women and 27% black patients. Mean metabolic equivalents (METs) achieved was 9.5 (SD 3.0). During a median follow-up period of 5.2 years (interquartile range 2.6-8.3 years), there were 6,851 new diabetes cases (14.6%). After adjustment, patients achieving ≥12 METs had a 54% lower risk of incident diabetes compared with patients achieving <6 METs (hazard ratio 0.46 [95% CI 0.41, 0.51]; P-trend < 0.001). This relationship was preserved across strata of age, sex, race, obesity, hypertension, and hyperlipidemia.

CONCLUSIONS

These data demonstrate that higher fitness is associated with a lower risk of incident diabetes regardless of demographic characteristics and baseline risk factors. Future studies should examine the association between change in fitness over time and incident diabetes.

Cardiac rehabilitation improves functional capacity and patient-reported health status in patients with continuous-flow left ventricular assist devices: the Rehab-VAD randomized controlled trial

OBJECTIVES

This study examined the effects of a cardiac rehabilitation (CR) program on functional capacity and health status (HS) in patients with newly implanted left ventricular assist devices (LVADs).

BACKGROUND

Reduced functional capacity and HS are independent predictors of mortality in patients with heart failure. CR improves both, and is related to improved outcomes in patients with heart failure; however, there is a paucity of data that describe the effects of CR in patients with LVADs.

METHODS

Enrolled subjects (n = 26; 7 women; age 55 ± 13 years; ejection fraction 21 ± 8%) completed a symptom-limited cardiopulmonary exercise test, the Kansas City Cardiomyopathy Questionnaire (KCCQ), a 6-min walk test (6MW), and single-leg isokinetic strength test before 2:1 randomization to CR versus usual care. Subjects in the CR group underwent 18 visits of aerobic exercise at 60% to 80% of heart rate reserve. Within-group changes from baseline to follow-up were analyzed with a paired t-test, whereas an independent t-test was used to determine differences in the change between groups.

RESULTS

Within-group improvements were observed in the CR group for peak oxygen uptake (10%), treadmill time (3.1 min), KCCQ score (14.4 points), 6MW distance (52.3 m), and leg strength (17%). Significant differences among groups were observed for KCCQ, leg strength, and total treadmill time.

CONCLUSIONS

Indicators of functional capacity and HS are improved in patients with continuous-flow LVADs who attend CR. Future trials should examine the mechanisms responsible for these improvements, and if such improvements translate into improved clinical outcomes. (Cardiac Rehabilitation in Patients With Continuous Flow Left Ventricular Assist Devices:Rehab VAD Trial [RehabVAD]; NCT01584895).