The association between cardiac rehabilitation and mortality risk for myocardial infarction patients with and without depressive symptoms

Causal Model Building in the Context of Cardiac Rehabilitation: A Systematic Review

Randomization is an effective design option to prevent bias from confounding in the evaluation of the causal effect of interventions on outcomes. However, in some cases, randomization is not possible, making subsequent adjustment for confounders essential to obtain valid results. Several methods exist to adjust for confounding, with multivariable modeling being among the most widely used. The main challenge is to determine which variables should be included in the causal model and to specify appropriate functional relations for continuous variables in the model. While the statistical literature gives a variety of recommendations on how to build multivariable regression models in practice, this guidance is often unknown to applied researchers. We set out to investigate the current practice of explanatory regression modeling to control confounding in the field of cardiac rehabilitation, for which mainly non-randomized observational studies are available. In particular, we conducted a systematic methods review to identify and compare statistical methodology with respect to statistical model building in the context of the existing recent systematic review CROS-II, which evaluated the prognostic effect of cardiac rehabilitation. CROS-II identified 28 observational studies, which were published between 2004 and 2018. Our methods review revealed that 24 (86%) of the included studies used methods to adjust for confounding. Of these, 11 (46%) mentioned how the variables were selected and two studies (8%) considered functional forms for continuous variables. The use of background knowledge for variable selection was barely reported and data-driven variable selection methods were applied frequently. We conclude that in the majority of studies, the methods used to develop models to investigate the effect of cardiac rehabilitation on outcomes do not meet common criteria for appropriate statistical model building and that reporting often lacks precision.

Do Cardiac Rehabilitation Affect Clinical Prognoses Such as Recurrence, Readmission, Revascularization, and Mortality After AMI?: Systematic Review and Meta-Analysis

Objective

We conducted a systematic review and meta-analysis to analyze the effects of cardiac rehabilitation (CR) on post-discharge prognoses of patients with acute myocardial infarction (AMI).

Methods

A literature search was conducted through four international medical and two Korean databases. Primary outcomes for the effectiveness of CR included all-cause mortality, cardiovascular mortality, recurrence, revascularization, major adverse cardiovascular event, major adverse cardiocerebrovascular event, and readmission. We summarized and analyzed results of studies about CR for AMI, including not only randomized controlled trials (RCTs) but also non-RCTs. We calculated the effect size separately by the study type.

Results

Fourteen articles were finally selected. Of these, two articles were RCTs, while 12 were non-RCTs. In RCTs, the overall mortality rate was lower in the group that participated in CR than that in the conventional care group by 28% (relative risk=0.72; 95% confidence interval, 0.34–1.57). Among non-RCTs, CR participation significantly decreased the overall risk of mortality. Moreover, the rates of recurrence and major adverse cardiovascular events were lower in the group that participated in CR compared to those in the non-CR group.

Conclusion

The meta-analysis shows that CR reduces the risk of re-hospitalization and all-cause mortality after AMI, compared to no participation in CR. This outcome was seen in RCTs as well as in non-RCTs. More studies are necessary for concrete conclusions about the beneficial effects of CR after AMI in various settings.

Effectiveness of comprehensive cardiac rehabilitation in coronary artery disease patients treated according to contemporary evidence based medicine: Update of the Cardiac Rehabilitation Outcome Study (CROS-II)

Background

Despite numerous studies and meta-analyses the prognostic effect of cardiac rehabilitation is still under debate. This update of the Cardiac Rehabilitation Outcome Study (CROS II) provides a contemporary and practice focused approach including only cardiac rehabilitation interventions based on published standards and core components to evaluate cardiac rehabilitation delivery and effectiveness in improving patient prognosis.

Design

A systematic review and meta-analysis.

Methods

Randomised controlled trials and retrospective and prospective controlled cohort studies evaluating patients after acute coronary syndrome, coronary artery bypass grafting or mixed populations with coronary artery disease published until September 2018 were included.

Results

Based on CROS inclusion criteria out of 7096 abstracts six additional studies including 8671 patients were identified (two randomised controlled trials, two retrospective controlled cohort studies, two prospective controlled cohort studies). In total, 31 studies including 228,337 patients were available for this meta-analysis (three randomised controlled trials, nine prospective controlled cohort studies, 19 retrospective controlled cohort studies; 50,653 patients after acute coronary syndrome 14,583, after coronary artery bypass grafting 163,101, mixed coronary artery disease populations; follow-up periods ranging from 9 months to 14 years). Heterogeneity in design, cardiac rehabilitation delivery, biometrical assessment and potential confounders was considerable. Controlled cohort studies showed a significantly reduced total mortality (primary endpoint) after cardiac rehabilitation participation in patients after acute coronary syndrome (prospective controlled cohort studies: hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.20–0.69; retrospective controlled cohort studies HR 0.64, 95% CI 0.53–0.76; prospective controlled cohort studies odds ratio 0.20, 95% CI 0.08–0.48), but the single randomised controlled trial fulfilling the CROS inclusion criteria showed neutral results. Cardiac rehabilitation participation was also associated with reduced total mortality in patients after coronary artery bypass grafting (retrospective controlled cohort studies HR 0.62, 95% CI 0.54–0.70, one single randomised controlled trial without fatal events), and in mixed coronary artery disease populations (retrospective controlled cohort studies HR 0.52, 95% CI 0.36–0.77; two out of 10 controlled cohort studies with neutral results).

Conclusion

CROS II confirms the effectiveness of cardiac rehabilitation participation after acute coronary syndrome and after coronary artery bypass grafting in actual clinical practice by reducing total mortality under the conditions of current evidence-based coronary artery disease treatment. The data of CROS II, however, underscore the urgent need to define internationally accepted minimal standards for cardiac rehabilitation delivery as well as for scientific evaluation.

Evaluation of cardiac rehabilitation on functional capacity in depressed and nondepressed patients after angioplasty

Background:

About 50% of the annual deaths in the developed countries are as a result of coronary artery disease. Several studies have shown the role of cardiac rehabilitation (CR) in improving cardiovascular indices including functional capacity, reducing depression, and mortality rates in cardiovascular patients. One of the psychological problems observed in cardiovascular patients is depression. Depression is one of the most important barriers to the treatment of heart attack, because it leads to denial of the disease and reduces the patient's motivation to continue treatment.

Objectives:

There are controversy information about the relationship between the effects of CR on these cases after angioplasty. The aim of this study was to evaluate the effect of CR on functional capacity in depressed and nondepressed patients after angioplasty in patients referred to Imam Khomeini, Ahvaz.

Methods:

This descriptive epidemiological study was performed on 54 patients referred for angioplasty. Functional capacity and depression score before and after participation in the 2-month CR program were evaluated in two groups of depressed and nondepressed patients. Data were analyzed by SPSS software, and the significance level was considered as P < 0.05.

Results:

The results of this study showed that in both the groups, the functional capacity after CR was significantly increased compared with the previous period (P < 0.001). Also in depressed patients, there was a significant decrease in depression scores (P < 0.001).

Conclusion:

Our findings showed improvement of functional capacity index following angioplasty, suggesting that patients participating in CR can be recommended by therapists. In addition, the results of this study showed that the participation in the CR program greatly affects the improvement of functional capacity and reduction in depression in patients undergoing angioplasty.

Residual Symptoms After Treatment for Depression in Patients With Coronary Heart Disease

OBJECTIVE

Depression is associated with an increased risk of mortality in patients with coronary heart disease (CHD). The risk may be reduced in patients who remit with adequate treatment, but few patients achieve complete remission. The purpose of this study was to identify the symptoms that persist despite aggressive treatment for depression in patients with CHD.

METHODS

One hundred twenty-five patients with stable CHD who met the DSM-IV criteria for a moderate-to-severe major depressive episode completed treatment with cognitive behavior therapy, either alone or combined with an antidepressant, for up to 16 weeks. Depression symptoms were assessed at baseline and after 16 weeks of treatment.

RESULTS

The M (SD) Beck Depression Inventory scores were 30.0 (8.6) at baseline and 8.3 (7.5) at 16 weeks. Seventy seven (61%) of the participants who completed treatment met remission criteria (Hamilton Rating Scale for Depression ≤7) at 16 weeks. Loss of energy and fatigue were the most common posttreatment symptoms both in remitters (n = 44, 57%; n = 34, 44.2%) and nonremitters (n = 42, 87.5%; n = 35, 72.9%). These symptoms were not predicted by baseline depression severity, anxiety, demographic, or medical variables including inflammatory markers or cardiac functioning or by medical events during depression treatment.

CONCLUSIONS

Fatigue and loss of energy often persist in patients with CHD even after otherwise successful treatment for major depression. These residual symptoms may increase the risks of relapse and mortality. Development of effective interventions for these persistent symptoms is a priority for future research.

Outpatient cardiac rehabilitation: Effects on patient improvement outcomes

OBJECTIVE

To determine if the Cardiac rehabilitation (CR) program had positive effects on the patient medically as well as effects on pathological risk factors, functional capacity, and mental health; and the extent to which targets for blood pressure (BP) control in patients with hypertension (HT) and diabetes mellitus (DM) are achieved.

METHODOLOGY

CR participant data was collected from 1st June 2014 until 31st December 2015 (19 months), which included: demographics, medical history, social history, medications, lipid profiles and anthropometric measurements. Additional data was collected on The Patient Health Questionnaire (PHQ-9) factors, and on the participants 6min walk test (6MWT). Study participants were eligible to participate in the study if they attended 10 or more CR program sessions out of 12 at the Calvary Public Hospital Canberra.

RESULTS

Seventy nine (79) participants participated in the study. Significant reductions in BP (n=79) (p=<0.05), blood LDL cholesterol levels (n=26) (p=<0.05), and improvements in participants PHQ-9 scores (n=79) (p=<0.001), and their 6MWT (n=78) (p=<0.001) were noted. Participants were also able to better manage their medication (p=<0.05). Importantly, results indicated that significant improvements (p=<0.05) were made in DM patients (n=18) diastolic BP, physical ability and depression and anxiety.

CONCLUSION

A CR program can reduce risk factors associated with CVD, and improves mental health and physical fitness of participants.

RESULTS

Indicated that the CR program reduces DM patient risk factors through improved physical fitness and reductions in depression and anxiety, leading to reduced risk of future cardiovascular and renal disease.

The prognostic effect of cardiac rehabilitation in the era of acute revascularisation and statin therapy: A systematic review and meta-analysis of randomized and non-randomized studies - The Cardiac Rehabilitation Outcome Study (CROS)

Background

The prognostic effect of multi-component cardiac rehabilitation (CR) in the modern era of statins and acute revascularisation remains controversial. Focusing on actual clinical practice, the aim was to evaluate the effect of CR on total mortality and other clinical endpoints after an acute coronary event.

Design

Structured review and meta-analysis.

Methods

Randomised controlled trials (RCTs), retrospective controlled cohort studies (rCCSs) and prospective controlled cohort studies (pCCSs) evaluating patients after acute coronary syndrome (ACS), coronary artery bypass grafting (CABG) or mixed populations with coronary artery disease (CAD) were included, provided the index event was in 1995 or later.

Results

Out of n = 18,534 abstracts, 25 studies were identified for final evaluation (RCT: n = 1; pCCS: n = 7; rCCS: n = 17), including n = 219,702 patients (after ACS: n = 46,338; after CABG: n = 14,583; mixed populations: n = 158,781; mean follow-up: 40 months). Heterogeneity in design, biometrical assessment of results and potential confounders was evident. CCSs evaluating ACS patients showed a significantly reduced mortality for CR participants (pCCS: hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.20–0.69; rCCS: HR 0.64, 95% CI 0.49–0.84; odds ratio 0.20, 95% CI 0.08–0.48), but the single RCT fulfilling Cardiac Rehabilitation Outcome Study (CROS) inclusion criteria showed neutral results. CR participation was also associated with reduced mortality after CABG (rCCS: HR 0.62, 95% CI 0.54–0.70) and in mixed CAD populations.

Conclusions

CR participation after ACS and CABG is associated with reduced mortality even in the modern era of CAD treatment. However, the heterogeneity of study designs and CR programmes highlights the need for defining internationally accepted standards in CR delivery and scientific evaluation.