Metrics details
To investigate the effect of an exercise-based cardiac rehabilitation program on the quality of life (QoL) of patients with chronic Chagas cardiomyopathy (CCC)
superiority randomized clinical trial of exercise training versus no exercise (control)
The sample comprised Chagas disease patients with CCC
left ventricular ejection fraction < 45%
without or with HF symptoms (CCC stages B2 or C
and at the end of six months of follow-up using the SF-36 questionnaire
Patients randomized for the exercise group (n = 15) performed exercise training (aerobic
strength and stretching exercises) for 60 min
Patients in the control group (n = 15) were not provided with a formal exercise prescription
Both groups received identical nutritional and pharmaceutical counseling during the study
Longitudinal analysis of the effects of exercise training on QoL
considering the interaction term (group × time) to estimate the rate of changes between groups in the outcomes (represented as beta coefficient)
Models were fitted adjusting for each respective baseline QoL value
There were significant improvements in physical functioning (β = + 10.7; p = 0.02)
role limitations due to physical problems (β = + 25.0; p = 0.01)
and social functioning (β = + 19.2; p < 0.01) scales during the first three months in the exercise compared to the control group
No significant differences were observed between groups after six months
Exercise-based cardiac rehabilitation provided short-term improvements in the physical and mental aspects of QoL of patients with CCC
Trial registration: ClinicalTrials.gov Identifier: NCT02517632; August 7
the impact of CR on QoL in CCC patients remains uncertain
Evaluating and comprehending these aspects is of paramount importance
considering the clinical complexities of the disease
Understanding QoL allows healthcare providers to tailor treatment plans and interventions to address not only the medical aspects of a condition
but also its impact on patients' overall well-being
resulting in a more effective and comprehensive care
we aimed to investigate the effect of an exercise-based CR program on the QoL of patients with CCC
We hypothesized that exercise training would improve both the physical and mental aspects of QoL in these patients
superiority randomized parallel-group clinical trial of exercise training versus no exercise training (control)
conducted from March 2015 to January 2017 at the Evandro Chagas National Institute of Infectious Diseases (INI) of the Oswaldo Cruz Foundation (Fiocruz)
Individuals followed at INI were sequentially recruited to participate in the study
The sample comprised CD patients (confirmed by two distinct serological tests) of both sexes
left ventricular ejection fraction (LVEF) < 45%
New York Heart Association (NYHA) functional class I or II during three months before study enrollment
clinically stable and under optimal medical therapy according to HF guidelines over the prior six weeks before study enrollment
Exclusion criteria were the presence of major comorbidities or limitations that could preclude exercise training
unavailability to attend exercise sessions 3 times a week
practice of regular exercise training at baseline (> 1 week) in the three months prior to the study
Sealed envelopes filled with a computer-generated sequence were used to randomly allocate the eligible patients between the two groups in a 1:1 ratio using WinPepi software
The sequence was generated in blocks and stratified according to CCC stages (B2 and C) by a single researcher who was not involved in the recruitment
26 participants were required (13 in the intervention group and 13 in the control group)
and maximal progressive cardiopulmonary exercise test (CPET) variables of the eligible patients were obtained during the initial assessment
Maximal symptom-limited CPET was performed on a treadmill (Inbramed
Brazil) with a ramp protocol and active recovery
USA) connected to a computerized Ergo PC Elite system (Micromed
in which the target heart rate ranged from 70% of maximum heart rate obtained in the CPET to the Hellerstein’s formula percentage in the first month
and from the Hellerstein’s formula percentage to 85% of maximum heart rate in the following months
Borg scale was used as an adjuvant of exercise intensity prescription (targeting 2–4 in CR10 Borg scale)
The intensity of exercise was controlled by an exercise physiologist that supervised all exercise sessions
All exercise sessions were center-based and carried out in the morning
in an indoor environment with controlled temperature and under a multidisciplinary supervision (including an exercise physiologist and physician)
No guidance was given to participants for home-based exercises (outside of the center-based program)
Patients in the control group were not provided with a formal exercise prescription
Descriptive analysis consisted of mean and standard deviation for continuous variables and number of observations and percentage for categorical variables
The longitudinal analysis of the effects of exercise-based CR on QoL was performed using mixed linear models
This approach enable us to assess the interaction term (group x time) to estimate the rate of changes between groups in the outcomes
All participants were considered in the statistical analysis
regardless of compliance or loss to follow-up
characterizing an intention-to-treat analysis
Line graphs were constructed to visually illustrate the crude trajectories of QoL scales during the follow-up in each group
The Research Electronic Data Capture (REDCap) web application was used for data management and the data analysis was conducted using Stata 13.0
Statistical significance was set at p ≤ 0.05 for all analyses
All participants received information about the goals and procedures of the study and voluntarily agreed to participate by means of signing a written informed consent
The study was performed in accordance to the resolution 466/2012 of the Brazilian National Council of Health and was approved by the Institutional Research Ethics Committee (CAAE: 38038914.6.0000.5262) in February
The clinical trial was registered at ClinicalTrials.gov (NCT02517632)
and follow-up of participants included in the study
Baseline characteristics of the patients included in each arm are shown in Table 1
The overall mean age was 59.8 (± 10.0) years
with the majority presenting stage C of CCC (73.3%)
patients presented lower scores in the physical scales compared to the mental scales
with the overall mean summary scores equal to 43.0 (± 9.8) for PCS and 53.0 (± 11.7) for MCS
The effects of physical exercise during the follow-up are depicted in Table 2, while Fig. 2 illustrates the crude trajectories for QoL scales during the follow-up in each group.
Estimated mean changes from baseline for quality of life
role limitations due to physical problems (β = + 25.0; p = 0.01) and social functioning (β = + 19.2; p < 0.01) scales during the first three months in the exercise group compared to the control group
no significant differences were observed between groups after six months of follow-up
The lack of evaluation of total physical activity levels during the study (besides attendance rates to training sessions) may also be ackowledged as a limitation
making difficult the identification of participants that changed their physical activity habits during the study
which may have driven our results to the null hypothesis
the sample was composed of patients regularly followed in a national reference center for treatment of infectious diseases
The sample size was calculated based only on primary outcome
which prevented us from conducting subgroup analysis
the study design with strict patient´s follow-up and the relatively long-term duration of the study are potential strengths
the main finding of the present study is that exercise-based CR provided short-term improvements in the physical and mental aspects of QoL of patients with CCC
These results are of great clinical meaning since CR is a simple and low-cost tool to improve patients' QoL
Future studies examining the dose–response relationship between exercise and QoL and potential influence of different lifestyle intervention strategies (isolated or combined) on long-term QoL responses are necessary to support clinical recommendations for patients with CCC
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request
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or other support were received during the preparation of this manuscript
Evandro Chagas National Institute of Infectious Disease
Fernanda de Souza Nogueira Sardinha Mendes
Pedro Emmanuel Alvarenga Americano do Brasil & Mauro Felippe Felix Mediano
Aloysio de Castro State Institute of Cardiology
Luiz Fernando Rodrigues Junior & Mauro Felippe Felix Mediano
Federal University of Jequitinhonha and Mucuri Valleys
Laboratory of Physical Activity and Health Promotion
Federal University of the State of Rio de Janeiro
contributed to the study conception and design and in data collection and treatment
The first draft of the manuscript was written by M.C.V
and all authors commented on previous versions of the manuscript
All authors read and approved the final manuscript
The authors declare no competing interests
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DOI: https://doi.org/10.1038/s41598-024-58776-3
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