Intensive Versus Traditional Cardiac Rehabilitation: Mortality and Cardiovascular Outcomes in a 2016-2020 Retrospective Medicare Cohort.

BACKGROUND: Traditional cardiac rehabilitation (CR) improves cardiovascular outcomes and reduces mortality, but less is known about the relative benefit of intensive CR (ICR) which incorporates greater lifestyle education through 72 sessions (versus 36 in CR). Our objective was to determine whether ICR is associated with a mortality and cardiovascular benefit compared with CR. METHODS: Retrospective cohort study of Medicare Fee-For-Service beneficiaries in a 100% sample, claims data set. Qualifying events were captured from May 1, 2016 to December 31, 2019 and ICR/CR utilization captured from May 1, 2016 to December 31, 2020. Among patients attending at least 1 day of either CR or ICR, Cox proportional hazards models using a 1 to 5 propensity score match were used to compare utilization and the association of ICR versus CR participation with (1) all-cause mortality and (2) cardiovascular-related hospitalizations or nonfatal cardiac events. Dose-response was assessed by the number of days attended. RESULTS: From 2016 to 2019, 1 277 358 unique patients met at least one qualifying indication for ICR/CR from 2016 to 2019. Of these, 262 579 (20.6%) and 4452 (0.4%) attended at least one session of CR or ICR, respectively (mean [SD] age, 73.2 [7.8] years; 32.3% female). In the matched sample, including 26 659 total patients (median, 2.4-year follow-up), ICR was associated with 12% lower all-cause mortality (multivariable adjusted hazard ratio, 0.88 [95% CI, 0.78-0.99]; P=0.036) compared with CR but no significant difference for cardiovascular-related hospitalization or nonfatal cardiac events. The mortality benefit was seen for both ICR and CR per day strata, with each modality demonstrating a clear dose-response benefit. CONCLUSIONS: ICR is associated with lower mortality than traditional CR among Medicare beneficiaries but no difference in cardiovascular-related hospitalization or nonfatal cardiac events. Moreover, ICR and CR demonstrate a dose-response relationship for mortality. Additional studies are needed to confirm these observations and to better understand the mechanisms by which ICR may lead to a reduction in mortality.

Prospective Study of the Impact of Outpatient Intensive Cardiac Rehabilitation on Diet Quality, Health-related Quality of Life, and Cardiovascular Health Indices.

Intensive cardiac rehabilitation (ICR) programs are approved by the Centers for Medicare & Medicaid Services on the basis of their expected benefits for cardiovascular disease (CVD) risk factors and health outcomes. However, the impact of outpatient ICR on diet quality, quality of life (QOL), and CVD risk factors has not been prospectively assessed. The aim of this cohort study was to test the hypothesis that patients enrolled in a Pritikin outpatient ICR program would show improved diet quality, QOL, and CVD health indexes, and that the improvements would be greater than those of patients in traditional cardiac rehabilitation (CR). Patients enrolled in ICR (n = 230) or CR (n = 62) were assessed at baseline and at visit 24. Diet quality was assessed using the Rate Your Plate questionnaire, and QOL was assessed through the Dartmouth COOP Functional Health Assessment questionnaire. Secondary end points included anthropometrics, CVD biomarkers, hemodynamics, and fitness. Patients in ICR programs displayed significant improvements at visit 24 versus baseline in Rate Your Plate and Dartmouth COOP Functional Health Assessment scores, weight, body mass index (BMI), waist circumference, fat mass, total and low-density lipoprotein cholesterol, 6-minute walk distance, and grip strength. Patients in ICR had greater improvements in diet quality (p = 0.001), weight (p = 0.001), and BMI (p <0.001) than did those in CR. In summary, this prospective study of Pritikin outpatient ICR revealed significant improvements in diet quality, QOL, adiposity, and other CVD risk factors. The improvements in diet quality, body weight, and BMI were greater than those observed with traditional CR.

Human total, basal and activity energy expenditures are independent of ambient environmental temperature.

Lower ambient temperature (Ta) requires greater energy expenditure to sustain body temperature. However, effects of Ta on human energetics may be buffered by environmental modification and behavioral compensation. We used the IAEA DLW database for adults in the USA (n = 3213) to determine the effect of Ta (-10 to +30°C) on TEE, basal (BEE) and activity energy expenditure (AEE) and physical activity level (PAL). There were no significant relationships (p > 0.05) between maximum, minimum and average Ta and TEE, BEE, AEE and PAL. After adjustment for fat-free mass, fat mass and age, statistically significant (p < 0.01) relationships between TEE, BEE and Ta emerged in females but the effect sizes were not biologically meaningful. Temperatures inside buildings are regulated at 18-25°C independent of latitude. Hence, adults in the US modify their environments to keep TEE constant across a wide range of external ambient temperatures.

Benefits of the First Pritikin Outpatient Intensive Cardiac Rehabilitation Program.

PURPOSE: Intensive cardiac rehabilitation (ICR) is a comprehensive, medically supervised exercise treatment program covered by Medicare for patients with approved cardiac diagnoses. The aim of this study was to determine the benefits of the first Pritikin outpatient ICR program. METHODS: This retrospective analysis included patients referred to ICR or traditional cardiac rehabilitation (CR) during the first 7 yr (2013-2019) at the first facility to implement Pritikin ICR. Intensive cardiac rehabilitation is composed of 36 education sessions on nutrition, exercise, and a healthy mindset, in addition to 36 monitored exercise sessions that comprise traditional CR. Assessments included anthropometrics (weight, body mass index, and waist circumference), dietary patterns, physical function (6-min walk test, [6MWT] Short Physical Performance Battery [SPPB: balance, 4-m walk, chair rise], handgrip strength), and health-related quality of life (Dartmouth COOP, 36-item Short Form Survey). Baseline and follow-up measures were compared within and between groups. RESULTS: A total of 1963 patients enrolled (1507 ICR, 456 CR, 66.1 ± 11.4 yr, 68% male, 82% overweight or obese); 1141 completed the program (58%). The ICR patients completed 22 exercise and 18 education sessions in 9.6 wk; CR patients completed 19 exercise sessions in 10.3 wk. ICR resulted in improvements ( P < .001 pre vs post) in all anthropometric measures, dietary patterns, 6MWT distance, all SPPB components, grip strength, and health-related quality of life. The improvements in anthropometrics and dietary patterns were greater in ICR than in CR. CONCLUSIONS: The Pritikin outpatient ICR program promoted improvements in several cardiovascular health indices. Critical next steps are to assess long-term health outcomes after ICR, including cardiac events and mortality.

Intensive Cardiac Rehabilitation Is Markedly Underutilized by Medicare Beneficiaries: RESULTS FROM A 2012-2016 NATIONAL SAMPLE.

PURPOSE: Intensive cardiac rehabilitation (ICR) was developed to enhance traditional cardiac rehabilitation (CR) by adding sessions focused on nutrition, lifestyle behaviors, and stress management. Intensive CR has been Medicare-approved since 2010, yet little is known about national utilization rates of ICR in the Medicare population or characteristics associated with its use. METHODS: A 5% sample of Medicare claims data from 2012 to 2016 was used to identify beneficiaries with a qualifying indication for ICR/CR and to quantify utilization of ICR or CR within 1 yr of the qualifying diagnosis. RESULTS: From 2012 to 2015, there were 107 246 patients with a qualifying indication. Overall, only 0.1% of qualifying patients participated in ICR and 16.2% in CR from 2012 to 2016, though utilization rates of both ICR and CR increased during this period (ICR 0.06 to 0.17%, CR 14.3 to 18.2%). The number of ICR centers increased from 15 to 50 over the same period. There were no differences between ICR and CR enrollees with respect to age, sex, race, discharge location, median income, dual enrollment, or number of comorbidities. Compared with eligible beneficiaries who did not attend ICR or CR, those who attended either program were younger, more likely to be male and White, and had higher median income. CONCLUSIONS: Although ICR and CR have a class 1 indication for the treatment of cardiovascular disease and the number of ICR centers has increased, ICR is not widely available and remains markedly underutilized. Continued research is needed to understand the barriers to program development and patient participation.

The Utility of Body Composition Assessment in Nutrition and Clinical Practice: An Overview of Current Methodology.

Body composition is a key component for maintaining good general health and longevity. It can be influenced by a variety of factors, including genetics, environment, and lifestyle choices. The assessment of body composition is an essential tool for nutrition specialists to effectively evaluate nutritional status and monitor progression during dietary interventions. As humans age, there is a natural increase in fat mass coupled with a gradual decline in lean mass, specifically in bone and muscle mass. Individuals with a high body fat percentage are at a greater risk of cardiovascular diseases, type 2 diabetes, several types of cancer, and early mortality. Significant decreases in bone mineral density signify osteopenia and osteoporosis, while reductions in skeletal muscle mass increase the risk of developing sarcopenia. Moreover, undernutrition exacerbates the effects of many medical conditions and is important to address. Though weight tracking and calculation of BMI are used commonly by clinicians and dietitians, these measures do not provide insight on the relative contributions of fat mass and fat-free mass or the changes in these compartments that may reflect disease risk. Therefore, it is important that healthcare professionals have a critical understanding of body composition assessment and the strengths and limitations of the methods available.

Body-composition changes in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE)-2 study: a 2-y randomized controlled trial of calorie restriction in nonobese humans.

Background: Calorie restriction (CR) retards aging and increases longevity in many animal models. However, it is unclear whether CR can be implemented in humans without adverse effects on body composition.Objective: We evaluated the effect of a 2-y CR regimen on body composition including the influence of sex and body mass index (BMI; in kg/m2) among participants enrolled in CALERIE-2 (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy), a multicenter, randomized controlled trial.Design: Participants were 218 nonobese (BMI: 21.9-28.0) adults aged 21-51 y who were randomly assigned to 25% CR (CR, n = 143) or ad libitum control (AL, n = 75) in a 2:1 ratio. Measures at baseline and 12 and 24 mo included body weight, waist circumference, fat mass (FM), fat-free mass (FFM), and appendicular mass by dual-energy X-ray absorptiometry; activity-related energy expenditure (AREE) by doubly labeled water; and dietary protein intake by self-report. Values are expressed as means ± SDs.Results: The CR group achieved 11.9% ± 0.7% CR over 2-y and had significant decreases in weight (-7.6 ± 0.3 compared with 0.4 ± 0.5 kg), waist circumference (-6.2 ± 0.4 compared with 0.9 ± 0.5 cm), FM (-5.4 ± 0.3 compared with 0.5 ± 0.4 kg), and FFM (-2.0 ± 0.2 compared with -0.0 ± 0.2 kg) at 24 mo relative to the AL group (all between-group P < 0.001). Moreover, FFM as a percentage of body weight at 24 mo was higher, and percentage of FM was lower in the CR group than in the AL. AREE, but not protein intake, predicted preservation of FFM during CR (P < 0.01). Men in the CR group lost significantly more trunk fat (P = 0.03) and FFM expressed as a percentage of weight loss (P < 0.001) than women in the CR group.Conclusions: Two years of CR had broadly favorable effects on both whole-body and regional adiposity that could facilitate health span in humans. The decrements in FFM were commensurate with the reduced body mass; although men in the CR group lost more FFM than the women did, the percentage of FFM in the men in the CR group was higher than at baseline. CALERIE was registered at clinicaltrials.gov as NCT00427193.

Energy expenditure and activity among Hadza hunter-gatherers.

OBJECTIVES: Studies of total energy expenditure, (TEE; kcal/day) among traditional populations have challenged current models relating habitual physical activity to daily energy requirements. Here, we examine the relationship between physical activity and TEE among traditional Hadza hunter-gatherers living in northern Tanzania. METHODS: Hadza adults were studied at two camps, with minimal intervention so as to monitor energy expenditure and activity during normal daily life. We measured daily walking distance and walking speed using wearable GPS units for 41 adults. For a subset of 30 adults, we measured TEE using doubly labeled water, three indices of work load (foraging return rate, maternal status, and number of dependent children), and urinary biomarkers of metabolic activity and stress (8-hydroxydeoxyguanosine, cortisol, and testosterone). RESULTS: Fat-free mass was the single strongest predictor of TEE among Hadza adults (r(2) = 0.66, P < 0.001). Hadza men used greater daily walking distances and faster walking speeds compared with that of Hadza women, but neither sex nor any measure of physical activity or work load were correlated with TEE in analyses controlling for fat-free mass. Compared with developed, industrial populations, Hadza adults had similar TEE but elevated levels of metabolic stress as measured by 8-hydroxydeoxyguanosine. CONCLUSION: Our results indicate that daily physical activity may not predict TEE within traditional hunter-gatherer populations like the Hadza. Instead, adults with high levels of habitual physical activity may adapt by reducing energy allocation to other physiological activity.

Bayesian functional integral method for inferring continuous data from discrete measurements.

Inference of the insulin secretion rate (ISR) from C-peptide measurements as a quantification of pancreatic ß-cell function is clinically important in diseases related to reduced insulin sensitivity and insulin action. ISR derived from C-peptide concentration is an example of nonparametric Bayesian model selection where a proposed ISR time-course is considered to be a "model". An inferred value of inaccessible continuous variables from discrete observable data is often problematic in biology and medicine, because it is a priori unclear how robust the inference is to the deletion of data points, and a closely related question, how much smoothness or continuity the data actually support. Predictions weighted by the posterior distribution can be cast as functional integrals as used in statistical field theory. Functional integrals are generally difficult to evaluate, especially for nonanalytic constraints such as positivity of the estimated parameters. We propose a computationally tractable method that uses the exact solution of an associated likelihood function as a prior probability distribution for a Markov-chain Monte Carlo evaluation of the posterior for the full model. As a concrete application of our method, we calculate the ISR from actual clinical C-peptide measurements in human subjects with varying degrees of insulin sensitivity. Our method demonstrates the feasibility of functional integral Bayesian model selection as a practical method for such data-driven inference, allowing the data to determine the smoothing timescale and the width of the prior probability distribution on the space of models. In particular, our model comparison method determines the discrete time-step for interpolation of the unobservable continuous variable that is supported by the data. Attempts to go to finer discrete time-steps lead to less likely models.

Design and conduct of the CALERIE study: comprehensive assessment of the long-term effects of reducing intake of energy.

BACKGROUND: In a robust and consistent manner, sustained caloric restriction (CR) has been shown to retard the aging process in a variety of animal species. Nonhuman primate studies suggest that CR may have similar effects in longer-lived species. The CALERIE (Comprehensive Assessment of the Long-term Effects of Reducing Intake of Energy) research program is the first systematic investigation of CR in nonobese human beings. In the phase 2 study, it is hypothesized that 2 years of sustained CR, involving a 25% reduction of ad libitum energy intake, results in beneficial effects similar to those observed in animal studies. This article presents the design and implementation of this study. METHODS: The study is a multicenter, parallel-group, randomized controlled trial. A sample of 225 participants (22.0 ≤ body mass index [BMI] < 28.0 kg/m(2)) is being enrolled with 2:1 allocation to CR. RESULTS: An intensive dietary and behavioral intervention was developed to achieve 25% CR and sustain it over the 2 years. Adherence is monitored using a doubly labeled water technique. Primary outcomes are resting metabolic rate and core temperature, and are assessed at baseline and at 6-month intervals. Secondary outcomes address oxyradical formation, cardiovascular risk markers, insulin sensitivity and secretion, immune function, neuroendocrine function, quality of life and cognitive function. Biologic materials are stored in a central repository. CONCLUSIONS: An intricate protocol has been developed to conduct this study. Procedures have been implemented to safeguard the integrity of the data and the conclusions drawn. The results will provide insight into the detrimental changes associated with the human aging process and how CR mitigates these effects.

Improvements in glucose tolerance and insulin action induced by increasing energy expenditure or decreasing energy intake: a randomized controlled trial.

BACKGROUND: Weight loss, through calorie restriction or increases in energy expenditure via exercise, improves glucose tolerance and insulin action. However, exercise-induced energy expenditure may further improve glucoregulation through mechanisms independent of weight loss. OBJECTIVE: The objective was to assess the hypothesis that weight loss through exercise-induced energy expenditure improves glucoregulation and circulating factors involved in insulin action to a greater extent than does similar weight loss through calorie restriction. DESIGN: Sedentary men and women aged 50-60 y with a body mass index (kg/m(2)) of 23.5-29.9 were randomly assigned to 1 of 2 weight-loss interventions [12 mo of exercise training (EX group; n = 18) or calorie restriction (CR group; n = 18)] or to a healthy lifestyle (HL) control group (n = 10). The insulin sensitivity index and areas under the curve for glucose and insulin were assessed with an oral-glucose-tolerance test. Adiponectin and tumor necrosis factor alpha concentrations were measured in fasting serum. Fat mass was measured by dual-energy X-ray absorptiometry. RESULTS: Yearlong energy deficits were not significantly different between the EX and CR groups, as evidenced by body weight and fat mass changes. The insulin sensitivity index increased and the glucose and insulin areas under the curve decreased in the EX and CR groups, remained unchanged in the HL group, and did not differ significantly between the EX and CR groups. Marginally significant increases in adiponectin and decreases in the ratio of tumor necrosis factor alpha to adiponectin occurred in the EX and CR groups but not in the HL group. CONCLUSIONS: Weight loss induced by exercise training or calorie restriction improves glucose tolerance and insulin action in nonobese, healthy, middle-aged men and women. However, it does not appear that exercise training-induced weight loss results in greater improvements than those that result from calorie restriction alone.