Mortality Benefits of Cardiac Rehabilitation in Coronary Artery Disease Are Mediated by Comprehensive Risk Factor Modification: A Retrospective Cohort Study

BACKGROUND

Cardiac rehabilitation (CR) is a multicomponent intervention to reduce adverse outcomes from coronary artery disease, but its mechanisms are not fully understood. The aims of this study were to examine the impact of CR on survival and cardiovascular risk factors, and to determine potential mediators between CR attendance and reduced mortality.

METHODS AND RESULTS

A retrospective mediation analysis was conducted among 11 196 patients referred to a 12-week CR program following an acute coronary syndrome event between 2009 and 2019. A panel of cardiovascular risk factors was assessed at a CR intake visit and repeated on CR completion. All-cause and cardiovascular mortality were ascertained via health care administrative data sets at mean 4.2-year follow-up (SD, 2.81 years). CR completion was associated with reduced all-cause (adjusted hazard ratio [HR], 0.67 [95% CI, 0.54-0.83]) and cardiovascular (adjusted HR, 0.57 [95% CI, 0.40-0.81]) mortality, as well as improved cardiorespiratory fitness, lipid profile, body composition, psychological distress, and smoking rates (P<0.001). CR attendance had an indirect effect on all-cause mortality via improved cardiorespiratory fitness (ab=-0.006 [95% CI, -0.008 to -0.003]) and via low-density lipoprotein cholesterol (ab=-0.002 [95% CI, -0.003 to -0.0003]) and had an indirect effect on cardiovascular mortality via cardiorespiratory fitness (ab=-0.007 [95% CI, -0.012 to -0.003]).

CONCLUSIONS

Cardiorespiratory fitness and lipid control partly explain the mortality benefits of CR and represent important secondary prevention targets.

An evaluation of the role of the exercise training dose for changes in exercise capacity following a standard cardiac rehabilitation program

BACKGROUND

To retrospectively characterize and compare the dose of exercise training (ET) within a large cohort of patients demonstrating different levels of improvement in exercise capacity following a cardiac rehabilitation (CR) program.

METHODS

A total of 2310 patients who completed a 12-week, center-based, guidelines-informed CR program between January 2018 and December 2019 were included in the analysis. Peak metabolic equivalents (MET_peak) were determined pre- and post-CR during which total duration (ET time) and intensity [percent of heart rate peak (%HR_peak)] of supervised ET were also obtained. Training responsiveness was quantified on the basis of changes in MET_peak from pre- to post-CR. A cluster analysis was performed to identity clusters demonstrating discrete levels of responsiveness (i.e., negative, low, moderate, high, and very-high). These were compared for several baseline and ET-derived variables which were also included in a multivariable linear regression model.

RESULTS

At pre-CR, baseline MET_peak was progressively lower with greater training responsiveness (F_(4,2305) = 44.2, P < 0.01, η²_p = 0.71). Likewise, average training duration (F_(4,2305) = 10.7 P < 0.01, η²_p = 0.02) and %HR_peak (F_(4,2305) = 25.1 P < 0.01, η²_p = 0.042) quantified during onsite ET sessions were progressively greater with greater training responsiveness. The multivariable linear regression model confirmed that baseline MET_peak, training duration and intensity during ET, BMI, and age (P < 0.001) were significant predictors of MET_peak post-CR.

CONCLUSIONS

Along with baseline MET_peak, delta BMI, and age, the dose of ET (i.e., training duration and intensity) predicts MET_peak at the conclusion of CR. A re-evaluation of current approaches for exercise intensity prescription is recommended to extend the benefits of completing CR to all patients.

Long-Term Maintenance of Cardiorespiratory Fitness Gains After Cardiac Rehabilitation Reduces Mortality Risk in Patients With Multimorbidity

PURPOSE

The objective of this study was to characterize the impact of multimorbidity and cardiorespiratory fitness (CRF) on mortality in patients completing cardiac rehabilitation (CR).

METHODS

This cohort study included data from patients with a history of cardiovascular disease (CVD) completing a 12-wk CR program between January 1996 and March 2016, with follow-up through March 2017. Patients were stratified by the presence of multimorbidity, which was defined as having a diagnosis of ≥2 noncommunicable diseases (NCDs). Cox regression analyses were used to evaluate the effects of multimorbidity and CRF on mortality in patients completing CR. Symptom-limited exercise tests were completed at baseline, immediately following CR (12 wk), with a subgroup completing another test at 1-yr follow-up. Peak metabolic equivalents (METs) were determined from treadmill speed and grade.

RESULTS

Of the 8320 patients (61 ± 10 yr, 82% male) included in the analyses, 5713 (69%) patients only had CVD diagnosis, 2232 (27%) had CVD+1 NCD, and 375 (4%) had CVD+≥2 NCDs. Peak METs at baseline (7.8 ± 2.0, 6.9 ± 2.0, 6.1 ± 1.9 METs), change in peak METs immediately following CR (0.98 ± 0.98, 0.83 ± 0.95, 0.76 ± 0.95 METs), and change in peak METs 1 yr after CR (0.98 ± 1.27, 0.75 ± 1.17, 0.36 ± 1.24 METs) were different ( P < .001) among the subgroups. Peak METs at 12 wk and the presence of coexisting conditions were each predictors ( P < .001) of mortality. Improvements in CRF by ≥0.5 METS from baseline to 1-yr follow-up among patients with or without multimorbidity were associated with lower mortality rates.

CONCLUSION

Increasing CRF by ≥0.5 METs improves survival regardless of multimorbidity status.

Cardiorespiratory fitness estimations and their ability to predict all-cause mortality in patients with cardiovascular disease

Background

In cardiac rehabilitation programs, cardiorespiratory fitness is commonly estimated (eCRF) from the maximum workload achieved on a graded exercise test. This study compared four well-established eCRF equations in their ability to predict mortality in patients with cardiovascular disease (CVD).

Methods

A total of 7269 individuals with CVD were studied (81% male; age 59.4 ± 10.3yr). eCRF was calculated using equations from the American College of Sports Medicine, Bruce et al., the Fitness Registry and the Importance of Exercise International Database, and McConnell and Clark. The eCRF from each equation was compared with a RMANOVA. Cox proportional hazard models assessed the relationship between the eCRF equations and mortality risk. The predictive ability of the models was compared using the concordance index.

Results

There were 284 deaths (85% male) over a follow-up period of 5.8 ± 2.8yr. Although differences in eCRF were observed between each equation (P < 0.05), the eCRF from each of the four equations was predictive of mortality (P < 0.05). The concordance index values for each of the models were the same (0.77) indicating similar predictive performance.

Conclusions

The four well-established eCRF equations did not differ in their ability to predict mortality in patients with CVD, indicating any could be used for this purpose. However, the differences in eCRF from each of the equations suggest potential differences in their ability to guide clinical care and should be the focus of future research.

Health psychology and behavioral medicine researchers in Canada: An environmental scan

The purpose of this study is to characterize contemporary Canadian health psychology through an environmental scan by identifying faculty, research productivity and strengths, and collaborator interconnectivity. Profiles at Canadian universities were reviewed for faculty with psychology doctorates and health psychology research programs. Publications were obtained through Google Scholar and PubMed (Jan/18-Mar/21). A total of 284 faculty were identified. Cancer, pain, and sleep were key research topics. The collaborator network analysis revealed that most were linked through a common network, with clusters organized around geography, topic, and trainee relationships. Canada is a unique and productive contributor to health psychology.

Prediction of Mortality in Coronary Artery Disease: Role of Machine Learning and Maximal Exercise Capacity

OBJECTIVE

To develop a prediction model for survival of patients with coronary artery disease (CAD) using health conditions beyond cardiovascular risk factors, including maximal exercise capacity, through the application of machine learning (ML) techniques.

METHODS

Analysis of data from a retrospective cohort linking clinical, administrative, and vital status databases from 1995 to 2016 was performed. Inclusion criteria were age 18 years or older, diagnosis of CAD, referral to a cardiac rehabilitation program, and available baseline exercise test results. Primary outcome was death from any cause. Feature selection was performed using supervised and unsupervised ML techniques. The final prognostic model used the survival tree (ST) algorithm.

RESULTS

From the cohort of 13,362 patients (60±11 years; 2400 [18%] women), 1577 died during a median follow-up of 8 years (interquartile range, 4 to 13 years), with an estimated survival of 67% up to 21 years. Feature selection revealed age and peak metabolic equivalents (METs) as the features with the greatest importance for mortality prediction. Using these 2 features, the ST generated a long-term prediction with a C-index of 0.729 by splitting patients in 8 clusters with different survival probabilities (P<.001). The ST root node was split by peak METs of 6.15 or less or more than 6.15, and each patient's subgroup was further split by age or other peak METs cut points.

CONCLUSION

Applying ML techniques, age and maximal exercise capacity accurately predict mortality in patients with CAD and outperform variables commonly used for decision-making in clinical practice. A novel and simple prognostic model was established, and maximal exercise capacity was further suggested to be one of the most powerful predictors of mortality in CAD.

The impact of patient education on knowledge, attitudes, and cardiac rehabilitation attendance among patients with coronary artery disease

OBJECTIVE

Patient education (PE) delivered during exercise-based cardiac rehabilitation (CR) aims to promote health behaviour change, including attendance at CR exercise sessions, by imparting knowledge about coronary artery disease (CAD) and improving CR-related attitudes. This study evaluated the impact of PE on aspects of patient motivation (i.e., CAD-related knowledge, attitudes towards CR) and exercise session attendance.

METHODS

Adults with CAD referred to a 12-week CR program were recruited. CAD knowledge, perceived necessity/suitability of CR, exercise concerns, and barriers to CR were assessed pre/post-PE, and at 12-week follow-up. CR exercise attendance was obtained by chart review.

RESULTS

Among 90 patients (60 ± 10 years; 88% men), CAD knowledge and perceived necessity of CR improved pre- to post-PE; gains persisted at 12-weeks. Stronger pre-CR intentions to attend exercise sessions predicted greater attendance. Greater knowledge gains did not predict improvements in CR attitudes or exercise attendance.

CONCLUSION

Whereas PE may be useful for improving knowledge and attitudes regarding CAD self-management, more formative research is needed to determine whether PE can promote CR attendance.

PRACTICE IMPLICATIONS

Cardiac PE programs may be more successful in promoting exercise attendance if they target patients' behavioural intentions to attend and attitudes toward CR, rather than focussing exclusively on imparting knowledge.

Identification of Patients With COPD in a Cardiac Rehabilitation Setting: THE COnCuR STUDY

PURPOSE

To examine the feasibility of screening for chronic obstructive pulmonary disease (COPD) in an outpatient cardiac rehabilitation (CR) setting and to evaluate the detection rate of COPD using a targeted screening protocol.

METHODS

A total of 95 patients (62.5 ± 10.0 yr; men, n = 77), >40-yr old with a history of smoking were included in the study sample. Each participant answered the 5-item Canadian Lung Health Test (CLHT) questionnaire assessing symptoms such as coughing, phlegm, wheezing, shortness of breath, and frequent colds. Endorsing ≥1 item was indicative of potential COPD and warranted pulmonary function testing (PFT) and/or spirometry to diagnose or rule out COPD.

RESULTS

The CLHT questionnaire identified 44 patients at risk for COPD, with an average of 1.9 ± 1.2 items endorsed. Of the patients who underwent PFT, 6 new cases of mild COPD were diagnosed, resulting in a true positive rate with CLHT screening of 19% and a false-positive rate of 81%.

CONCLUSIONS

Implementing the CLHT to patients referred to CR correctly identified COPD in <20% of cases. Using the CLHT to screen for COPD prior to starting CR may not be optimal, due to disparities between true- and false-positive rates.

Cardiometabolic responses to cardiac rehabilitation in people with and without diabetes

BACKGROUND

Type 2 diabetes and cardiometabolic comorbidities manifesting as the metabolic syndrome (MetS) are highly prevalent in coronary heart disease (CHD) patients attending cardiac rehabilitation (CR). The study aimed to determine the prevalence of cardiometabolic derangements and MetS, and compare post-CR clinical responses in a large cohort of CHD patients with and without diabetes.

METHODS

Analyses were conducted on 3953 CHD patients [age: 61.1 ± 10.5 years; 741 (18.7%) with diabetes] that completed a representative 12-week CR program. A propensity model was used to match patients with diabetes (n = 731) to those without diabetes (n = 731) on baseline and clinical characteristics.

RESULTS

Diabetic patients experienced smaller improvements in metabolic parameters after completing CR, including abdominal obesity, and lipid profiles (all P ≤ .002), compared to non-diabetic patients. For both groups, there were similar improvement rates in peak metabolic equivalents ([METs]; P < .001); however, peak METs remained lower at 12-weeks in patients with diabetes than without diabetes. At baseline, the combined prevalence of insulin resistance (IR) and diabetes was 57.3%, whereas IR was present in 48.2% of non-diabetic patients, of which rates were reduced to 48.2% and 32.8% after CR, respectively. Accordingly, MetS prevalence decreased from 25.5% to 22.3% in diabetic versus 20.0% to 13.4% in non-diabetic patients (all P ≤ .004).

CONCLUSIONS

Completing CR appears to provide comprehensive risk reduction in cardio-metabolic parameters associated with diabetes and MetS; however, CHD patients with diabetes may require additional and more aggressive attention towards all MetS criteria over the course of CR in order to prevent future cardiovascular events.

Bridging the intention-behavior gap for cardiac rehabilitation participation: the role of perceived barriers. Disabil Rehabil 2018;42:1284-1291. [PMID: 30457017 DOI: 10.1080/09638288.2018.1524519]

Purpose: Patients referred to cardiac rehabilitation after an acute coronary syndrome event commonly report strong intention to attend, but at least one-third do not participate. This study explored whether well-documented cardiac rehabilitation barriers (e.g., comorbidities, logistical/time constraints, and low social support) moderate the association between intention to participate and actual program enrollment and attendance.Method: Following referral but prior to commencing a 12-week outpatient cardiac rehabilitation program, 100 patients with acute coronary syndrome completed measures of intention to attend cardiac rehabilitation, perceived cardiac rehabilitation barriers, and social support. Program enrollment and attendance were determined by chart review.Results: Despite high reported intention to attend (M = 6.08/7.00, SD = 1.80), nearly one-in-five did not enroll. Weaker intention to attend (b = 0.46, SE = 0.16, p = 0.004) and greater cardiac rehabilitation barriers (b= -1.67, SE = 0.70, p = 0.017) corresponded to lower program enrollment. Similarly, weaker intention (b = 2.29, SE = 0.50, p < 0.001) and greater barriers (b =-6.19, SE = 1.55, p < 0.001) predicted poorer attendance. Barriers moderated the association between intention to participate and cardiac rehabilitation enrollment (b=-0.60, SE = 0.29, p = 0.037) and attendance (b = -3.12, SE = 1.02, p = 0.003).Conclusions: Perceived cardiac rehabilitation barriers influence whether patients successfully translate their intention to attend into actual program participation. Enhancing self-efficacy to overcome barriers may represent an important intervention target among prospective cardiac rehabilitation patients.Implications for RehabilitationPatients with acute coronary syndrome report strong intention to attend cardiac rehabilitation upon referral, yet cardiac rehabilitation programs remain underutilized.Assessing and addressing perceived barriers during the transition to cardiac rehabilitation, even when patients present as highly motivated to attend, may be critical to promoting program uptake.Rehabilitation professionals should ask patients about specific barriers to attending cardiac rehabilitation (e.g., financial constraints, transportation problems) and provide individualized solutions (e.g., fee subsidization, home- or web-based programs) to increase participation.

The evaluation of a brief motivational intervention to promote intention to participate in cardiac rehabilitation: A randomized controlled trial

OBJECTIVES

Cardiac rehabilitation (CR) is an effective treatment for cardiovascular disease, yet many referred patients do not participate. Motivational interviewing could be beneficial in this context, but efficacy with prospective CR patients has not been examined. This study investigated the impact of motivational interviewing on intention to participate in CR.

METHODS

Individuals recovering from acute coronary syndrome (n = 96) were randomized to motivational interviewing or usual care, following CR referral but before CR enrollment. The primary outcome was intention to attend CR. Secondary outcomes included CR beliefs, barriers, self-efficacy, illness perception, social support, intervention acceptability, and CR participation.

RESULTS

Compared to those in usual care, patients who received the motivational intervention reported higher intention to attend CR (p = .001), viewed CR as more necessary (p = .036), had fewer concerns about exercise (p = .011), and attended more exercise sessions (p = .008). There was an indirect effect of the intervention on CR enrollment (b = 0.45, 95% CI 0.04-1.18) and CR adherence (b = 2.59, 95% CI 0.95-5.03) via higher levels of intention. Overall, patients reported high intention to attend CR (M = 6.20/7.00, SD = 1.67), most (85%) enrolled, and they attended an average of 65% of scheduled CR sessions.

CONCLUSION

A single collaborative conversation about CR can increase both intention to attend CR and actual program adherence.

PRACTICE IMPLICATIONS

The findings will inform future efforts to optimize behavioral interventions to enhance CR participation.

Sleeping for Two: An Open-Pilot Study of Cognitive Behavioral Therapy for Insomnia in Pregnancy

Insomnia and disturbed sleep are common during pregnancy. This study investigated the effectiveness of group cognitive-behavioral therapy for insomnia (CBT-I) delivered in pregnancy. Thirteen pregnant women with insomnia participated in five weekly CBT-I group sessions. All participants completed the study and provided baseline and follow-up data. Significant reductions in insomnia symptoms and increases in subjective sleep quality were observed over the course of the study. Diary and actigraphy assessments of sleep also changed, such that participants reported less time in bed (TIB), shorter sleep onset latency (SOL), increased sleep efficiency (SE), and increased subjective total sleep time (TST). Additionally, symptoms of depression, pregnancy-specific anxiety, and fatigue all decreased over the course of treatment. Effect sizes ranged from medium to large. CBT-I delivered during pregnancy was associated with significant improvements in sleep and mood. The next step in this area of inquiry is to better establish effectiveness via a randomized controlled trial.

Insomnia symptoms and heart rate recovery among patients in cardiac rehabilitation

Insomnia symptoms (i.e., difficulty falling asleep, difficulty staying asleep, and early morning awakenings) are common among people with cardiovascular disease, and have been linked to adverse cardiovascular health outcomes. Reduced parasympathetic tone is one pathway through which risk may be conferred. The purpose of this study was to evaluate whether insomnia symptoms are associated with lower parasympathetic tone in cardiac rehabilitation patients with suspected insomnia. Participants (N = 121) completed a self-report measure of insomnia severity. 1-min heart rate recovery (HRR), an index of parasympathetic tone, was obtained during a maximal exercise test. Difficulty falling asleep, but not difficulty staying asleep or early awakenings, was associated with attenuated 1-min HRR. When analyses were restricted to participants with moderate and severe insomnia severity (n = 51), the strength of this association increased. In a sample of cardiac rehabilitation patients with insomnia, only the symptom of difficulty falling asleep was associated with lower parasympathetic tone, suggesting that individual insomnia symptoms may show specificity in their associations with physiological mechanisms.

The role of maternal cardiac vagal control in the association between depressive symptoms and gestational hypertension

Reduced cardiac vagal control, indexed by relatively lower high-frequency heart rate variability (HF-HRV), is implicated in depressed mood and hypertensive disorders among non-pregnant adults whereas research in pregnancy is limited. This study examined whether maternal HF-HRV during pregnancy mediates the association between depressed mood and gestational hypertension. Depressive symptoms (Edinburgh Depression Scale) and HF-HRV were measured during early (M=14.9 weeks) and late (M=32.4 weeks) pregnancy in 287 women. Gestational hypertension was determined by chart review. Depressive symptoms were associated with less HF-HRV (b=-0.02, p=.001). There was an indirect effect of depressed mood on gestational hypertension through late pregnancy HF-HRV (b=0.04, 95% CI 0.0038, 0.1028) after accounting for heart rate. These findings suggest cardiac vagal control is a possible pathway through which prenatal depressed mood is associated with gestational hypertension, though causal ordering remains uncertain.

The Comparative Impact of Mindfulness-Based Cancer Recovery (MBCR) and Cognitive Behavior Therapy for Insomnia (CBT-I) on Sleep and Mindfulness in Cancer Patients

BACKGROUND

Insomnia is an important but often overlooked side effect of cancer. Dysfunctional sleep beliefs have been identified as an important perpetuating factor for insomnia. Mindfulness practice has been demonstrated to improve sleep quality but it is unknown whether these effects relate to changes in dysfunctional sleep beliefs.

PURPOSE

This study is a secondary analysis of a randomized controlled trial comparing mindfulness-based cancer recovery (MBCR) to cognitive behavior therapy for insomnia (CBT-I) in cancer patients with insomnia. This present analysis compares program impact on mindfulness, dysfunctional sleep beliefs, and insomnia severity clinical cutoffs.

METHODS

Patients (MBCR, n = 32; CBT-I, n = 40) were assessed at baseline, post-program, and 3-month follow-up.

RESULTS

Across both groups, patients showed improvements over time in acting with awareness (P = .021) and not judging experiences (P = .023). Changes in dysfunctional sleep beliefs produced by the CBT-I group exceeded those produced by MBCR at post-program and follow-up (P < .001). Acting with awareness, non-judging, and non-reacting were the facets of mindfulness associated with an overall reduction in dysfunctional sleep beliefs. There were no significant differences between the MBCR and CBT-I groups in the percentage of patients exceeding insomnia severity clinical cutoffs at post-program or follow-up.

CONCLUSIONS

This study supports the use of both CBT-I and MBCR to reduce insomnia severity and suggests the development of mindfulness facets as a method of reducing dysfunctional sleep beliefs.

The impact of mindfulness-based interventions on symptom burden, positive psychological outcomes, and biomarkers in cancer patients

Research on the use of mindfulness-based stress reduction and related mindfulness-based interventions (MBIs) in cancer care has proliferated over the past decade. MBIs have aimed to facilitate physical and emotional adjustment to life with cancer through the cultivation and practice of mindfulness (ie, purposeful, nonjudgmental, moment-to-moment awareness). This descriptive review highlights three categories of outcomes that have been evaluated in MBI research with cancer patients - namely, symptom reduction, positive psychological growth, and biological outcomes. We also examine the clinical relevance of each targeted outcome, while describing recently published original studies to highlight novel applications of MBIs tailored to individuals with cancer. Accumulating evidence suggests that participation in a MBI contributes to reductions in psychological distress, sleep disturbance, and fatigue, and promotes personal growth in areas such as quality of life and spirituality. MBIs may also influence markers of immune function, hypothalamic-pituitary-adrenal axis regulation, and autonomic nervous system activity, though it remains unclear whether these biological changes translate to clinically important health benefits. We conclude by discussing methodological limitations of the extant literature, and implications of matching MBIs to the needs and preferences of cancer patients. Overall, the growing popularity of MBIs in cancer care must be balanced against scientific evidence for their impact on specific clinical outcomes.

Ethical issues in the psychosocial assessment of bariatric surgery candidates

Psychosocial evaluation is recommended prior to bariatric surgery. Practice guidelines have been published on assessment methods for bariatric surgery candidates, but they have not emphasized ethical issues with this population. This review outlines ethical and professional considerations for behavioral healthcare providers who conduct pre-surgical assessments of bariatric surgery candidates by merging ethical principles for mental health professionals with current practices in pre-surgical assessments. Issues discussed include the following: (a) establishing and maintaining competence, (b) obtaining informed consent, (c) respecting confidentiality, (d) avoiding bias and discrimination, (e) avoiding and addressing dual roles, (f) selecting and using psychological tests, and (g) acknowledging limitations of psychosocial assessments.