Corrigendum: Home-based exercise program in the indeterminate form of Chagas disease (PEDI-CHAGAS study): a study protocol for a randomized clinical trial.

[This corrects the article DOI: 10.3389/fmed.2022.1087188.].

Biomarkers and Echocardiographic Predictors of Cardiovascular Outcome in Patients With Chronic Chagas Disease.

Background Chagas disease (CD) presents an ominous prognosis. The predictive value of biomarkers and new echocardiogram parameters in adjusted models have not been well studied. Methods and Results There were 361 patients with chronic CD (57.6% men, 61±11 years of age, clinical forms: indeterminate 27.1%, cardiac 56.6%, digestive 3.6%, cardiodigestive 12.7%) included in this single-center, observational, prospective longitudinal study. Echocardiographic evaluation included strain analyses of left atrial, left ventricular (LV), and right ventricular and 3-dimensional analyses of left atrial and LV volumes. Biomarkers included cardiac troponin I, brain natriuretic peptide, transforming growth factor ß1, tumor necrosis factor, matrix metalloproteinases, and Trypanosoma cruzi polymerase chain reaction. The studied end point was a composite of CD-related mortality, heart transplant, hospital admission due to worsening heart failure, or new cardiac device insertion. Event-free survival was analyzed by multivariable regression analyses adjusted for competing risks. P values <0.05 were considered significant. The composite event occurred in 79 patients after 4.9±2.0 years follow-up. LV end-diastolic volume (hazard ratio [HR], 1.01 [95% CI, 1.00-1.02]; P=0.02), peak negative global atrial strain (HR, 1.08 [95% CI, 1.00-1.17]; P=0.04), LV global circumferential strain (HR, 1.12 [95% CI, 1.04-1.21]; P=0.003), LV torsion (HR, 0.55 [95% CI, 0.35-0.81]; P=0.003), brain natriuretic peptide (HR, 2.03 [95% CI, 1.23-3.34]; P=0.005), and positive T cruzi polymerase chain reaction (HR, 1.80 [95% CI, 1.12-2.91]; P=0.01) were end point predictors independent from age, sex, 2-dimensional echocardiographic indexes, hypertension, previous cardiac device, and CD cardiac form. Conclusions Two-dimensional strain- and 3-dimensional-derived parameters, brain natriuretic peptide, and positive T cruzi polymerase chain reaction can be useful for prediction of CD cardiovascular events.

Socio-epidemiological factors and comorbidities associated with Chagas disease manifestations in two urban reference health care centres in Rio de Janeiro, Brazil.

BACKGROUND: Chagas disease (CD) is still an important public health issue in Latin America. This study aims to analyse the association between socio-epidemiological factors and comorbidities with clinical manifestations of CD. METHODS: We performed a cross-sectional study of 985 adult patients (65±11 y; 59.5% women) with CD. Data collection was based on questionnaires and medical records review. CD clinical forms (indeterminate, digestive, cardiac and cardiodigestive) and the stages of the cardiac form were classified according to the II Brazilian Consensus on CD. Statistical analyses were based on univariate and multivariate logistic regression. RESULTS: Older age and Brazilian birth state (Minas Gerais and Bahia) were associated with a greater likelihood of the cardiac form of CD. A greater likelihood of the digestive form was seen in men and those of older age. Patients with arterial hypertension and diabetes were less likely to have the digestive form. Men had a greater likelihood of having a more severe cardiac presentation. Those from Minas Gerais and Bahia states had a greater likelihood of having stage B1 or B2. CONCLUSIONS: The results reinforce the aging of the CD population living in urban areas in Brazil, the high prevalence of comorbidities and that epidemiology, sex and the presence of comorbidities may be related to the clinical form of CD.

Association of non-chronic low back pain with physical function, endurance, fatigability, and quality of life in middle- and older-aged adults: Findings from Baltimore Longitudinal Study of Aging.

Low back pain (LBP) is an important condition associated with high healthcare burden. However, the relationship of this condition with physical function (PF) and health-related quality of life (HRQoL) remains unclear. This is a cross-sectional study that aims to investigate the association between presence and intensity of non-chronic LBP with PF and HRQoL in middle-and older-aged adults. Participants answered questions about presence and intensity of LBP in the previous year, self-reported their PF and HRQoL (SF-12), and underwent objective measures of PF ([ExSPPB] including usual gait speed, narrow walk, chair stands, and standing balance), endurance performance ([EP] long-distance corridor walk) and fatigability. Generalized linear models and logistic regression models were performed. A total of 1500 participants (52.5% women, 70.3% white) aged 69.0 (SD 13.1) years were included. Of those, 642 (42.8%) reported LBP and the mean pain intensity was 4.1 (SD 2.2). After adjustments for potential confounders, presence of LBP was associated with lower self-reported PF (OR 1.73, 95% CI 1.27 to 2.37), lower physical component of HRQoL (ß -0.03, 95% CI -0.04 to -0.02) and poorer chair stand performance (ß -0.05, 95% CI -0.09 to -0.008). Higher intensity of LBP was associated with lower physical component of HRQoL (ß -0.01, 95% CI -0.02 to -0.007), poorer ExSPPB performance (ß -0.01, 95% CI -0.02 to -0.004), slower usual gait speed (ß -0.01, 95% CI -0.02 to -0.004), lower total standing balance time (ß -0.01, 95% CI -0.02 to -0.001) and higher fatigability (OR 1.13, 95% CI 1.01 to 1.25). The presence of non-chronic LBP was more consistently associated with lower self-reported PF, while higher intensity non-chronic LBP was associated with poorer objectively measured PF and fatigability. Collectively, this evidence suggests that although presence of pain may affect perception of function, greater pain intensity appears more strongly associated with unfavorable functional performance in mid-to-late life.

The association of exercise test variables with long-term mortality in patients with chronic Chagas disease.

Background: The identification of variables obtained in the exercise test (ET) associated with increased risk of death is clinically relevant and would provide additional information for the management of Chagas disease (CD). The objective of the present study was to evaluate the association of ET variables with mortality in patients with chronic CD. Methods: This retrospective longitudinal observational study included 232 patients (median age 46.0 years; 50% women) with CD that were followed at the Evandro Chagas National Institute of Infectious Diseases (Rio de Janeiro, Brazil) and performed an ET between 1989 and 2000. The outcome of interest was all-cause mortality. Results: There were 103 deaths (44.4%) during a median follow-up of 21.5 years (IQR 25-75% 8.0-27.8), resulting in 24.5 per 1,000 patients/year incidence rate. The ET variables associated with mortality after adjustments for potential confounders were increased maximal (HR 1.02; 95% CI 1.00-1.03 per mmHg) and change (HR 1.03; 95% CI 1.01-1.06 per mmHg) of diastolic blood pressure (DBP) during ET, ventricular tachycardia at rest (HR 3.95; 95% CI 1.14-13.74), during exercise (HR 2.73; 95% CI 1.44-5.20), and recovery (HR 2.60; 95% CI 1.14-5.91), and premature ventricular complexes during recovery (HR 2.06; 1.33-3.21). Conclusion: Our findings suggest that ET provides important prognostic value for mortality risk assessment in patients with CD, with hemodynamic (increased DBP during exercise) and electrocardiographic (presence of ventricular arrhythmias) variables independently associated with an increased mortality risk in patients with CD. The identification of individuals at higher mortality risk can facilitate the development of intervention strategies (e.g., close follow-up) that may potentially have an impact on the longevity of patients with CD.

Selenium, TGF-Beta and Infectious Endemic Cardiopathy: Lessons from Benchwork to Clinical Application in Chagas Disease.

For over 60 years, selenium (Se) has been known as an essential microelement to many biological functions, including cardiovascular homeostasis. This review presents a compilation of studies conducted in the past 20 years related to chronic Chagas disease cardiomyopathy (CCC), caused by Trypanosoma cruzi infection, a neglected disease that represents a global burden, especially in Latin America. Experimental and clinical data indicate that Se may be used as a complementary therapy to prevent heart failure and improve heart function. Starting from the main questions "Is Se deficiency related to heart inflammation and arrhythmogenesis in CCC?" and "Could Se be recommended as a therapeutic strategy for CCC?", we show evidence implicating the complex and multidetermined CCC physiopathology, discussing its possible interplays with the multifunctional cytokine TGF-ß as regulators of immune response and fibrosis. We present two new proposals to face this global public health challenge in vulnerable populations affected by this parasitic disease: fibrosis modulation mediated by TGF-ß pathways and the possible use of selenoproteins as antioxidants regulating the increased reactive oxygen stress present in CCC inflammatory environments. We assess the opportunity to consider the beneficial effects of Se in preventing heart failure as a concept to be applied for CCC patients.

Home-based exercise program in the indeterminate form of Chagas disease (PEDI-CHAGAS study): A study protocol for a randomized clinical trial.

Background: Chagas disease (CD) is a neglected endemic disease with worldwide impact due to migration. Approximately 50-70% of individuals in the chronic phase of CD present the indeterminate form, characterized by parasitological and/or serological evidence of Trypanosoma cruzi infection, but without clinical signs and symptoms. Subclinical abnormalities have been reported in indeterminate form of CD, including pro-inflammatory states and alterations in cardiac function, biomarkers and autonomic modulation. Moreover, individuals with CD are usually impacted on their personal and professional life, making social insertion difficult and impacting their mental health and quality of life (QoL). Physical exercise has been acknowledged as an important strategy to prevent and control numerous chronic-degenerative diseases, but unexplored in individuals with the indeterminate form of CD. The PEDI-CHAGAS study (which stands for "Home-Based Exercise Program in the Indeterminate Form of Chagas Disease" in Portuguese) aims to evaluate the effects of a home-based exercise program on physical and mental health outcomes in individuals with indeterminate form of CD. Methods and design: The PEDI-CHAGAS is a two-arm (exercise and control) phase 3 superiority randomized clinical trial including patients with indeterminate form of CD. The exclusion criteria are <18 years old, evidence of non-Chagasic cardiomyopathy, musculoskeletal or cognitive limitations that preclude the realization of exercise protocol, clinical contraindication for regular exercise, and regular physical exercise (≥1 × per week). Participants will be assessed at baseline, and after three and 6 months of follow-up. The primary outcome will be QoL. Secondary outcomes will include blood pressure, physical fitness components, nutritional status, fatigability, autonomic modulation, cardiac morphology and function, low back pain, depression and anxiety, stress, sleep quality, medication use and adherence, and biochemical, inflammatory and cardiac biomarkers. Participants in the intervention group will undergo a home-based exercise program whilst those in the control group will receive only general information regarding the benefits of physical activity. Both groups will receive the same general nutritional counseling consisting of general orientations about healthy diets. Conclusion: The findings from the present study may support public health intervention strategies to improve physical and mental health parameters to be implemented more effectively in this population. Clinical trial registration: [https://ensaiosclinicos.gov.br/rg/RBR-10yxgcr9/], identifier [U1111-1263-0153].

Association of Physical Activity With Maximal and Submaximal Tests of Exercise Capacity in Middle- and Older-Aged Adults.

Although physical activity (PA) is an important determinant of exercise capacity, the association between these constructs is modest. The authors investigated the associations of self-reported and objectively measured PA with maximal and submaximal tests of exercise capacity. Participants aged ≥40 years (N = 413; 49.6% female) completed a PA questionnaire, wore a uniaxial accelerometer (5.2 ± 1.1 days), and performed maximal (cardiopulmonary exercise test [CPET]) and submaximal (long-distance corridor walk) tests with indirect calorimetry (oxygen consumption, V˙O2). Linear regression models were fitted to assess the variation in exercise capacity explained (partial eta squared, η2) by PA variables. Accelerometer-measured vigorous (η2 = 22% female; η2 = 16% male) and total PA (η2 = 17% female; η2 = 13% male) explained the most variance in CPET V˙O2 (p < .001). All η2 values were lower for long-distance corridor walk V˙O2 (η2 ≤ 11%). Age contributed more to CPET V˙O2 than any PA variable in males (η2 = 32%), but not in females (η2 = 19%). Vigorous and total PA play important roles in CPET V˙O2 in mid to late life.

Effects of Selenium treatment on cardiac function in Chagas heart disease: Results from the STCC randomized Trial.

BACKGROUND: Chagas disease (caused by Trypanosoma cruzi infection) evolves to chronic chagasic cardiomyopathy (CCC) affecting 1.8 million people worldwide. This is the first randomized, placebo-controlled, double-blinded, clinical trial designed to estimate efficacy and safety of selenium (Se) treatment in CCC. METHODS: 66 patients with CCC stages B1 (left ventricular ejection fraction [LVEF] > 45% and no heart failure; n = 54) or B2 (LVEF < 45% and no heart failure; n = 12) were randomly assigned to receive 100 mcg/day sodium selenite (Se, n = 32) or placebo (Pla, n = 34) for one year (study period: May 2014-September 2018). LVEF changes over time and adverse effects were investigated. Trial registration number: NCT00875173 (clinicaltrials.gov). FINDINGS: No significant differences between the two groups were observed for the primary outcome: mean LVEF after 6 (ß= +1.1 p = 0.51 for Se vs Pla) and 12 months (ß= +2.1; p = 0.23). In a subgroup analysis, statistically significant longitudinal changes were observed for mean LVEF in the stage B2 subgroup (ß= +10.1; p = 0.02 for Se [n = 4] vs Pla [n = 8]). Se treatment was safe for CCC patients, and the few adverse effects observed were similarly distributed across the two groups. INTERPRETATION: Se treatment did not improve cardiac function (evaluated from LVEF) in CCC. However, in the subgroup of patients at B2 stage, a potential beneficial influence of Se was observed. Complementary studies are necessary to explore diverse Se dose and/or associations in different CCC stages (B2 and C), as well as in A and B1 stages with longer follow-up. FUNDING: Brazilian Ministry of Health, Fiocruz, CNPq, FAPERJ.

Effectiveness of a school-based randomized controlled trial aimed at increasing physical activity time in adolescents.

BACKGROUND: This study aimed to evaluate the effectiveness of obesity prevention educational activities, isolated or combined with the modification of the school environment on total physical activity time. METHODS: This is a school-based randomized controlled trial, conducted with 2511 students from fifth and sixth-grade in Brazil, that employed a parallel, three-group experimental arms: control group (CG), PAAPPAS group (PG) and PAAPPAS-environment group (PEG). During the 2016 school year, the PG received educational activities in the classroom, providing a general basis for a healthy lifestyle. The PEG received the same educational activities and also modifications in the school environment to stimulate physical activity practice during one month. Physical activity was evaluated through a validated physical activity questionnaire. Intention-to-treat analysis was performed to evaluate the rate of change of physical activity time between groups using PROC GENMOD procedure. All analyses were performed using SAS. RESULTS: Total physical activity time increased by 22% in PEG compared with CG (P = 0.003). No difference was observed between PEG and PG (Δ = 60.20 vs. 36.37, respectively; P = 0.27) and between PG and CG (Δ = 36.37 vs. 9.70, respectively; P = 0.23). The proportion of individuals who attended at least 150 min week-1 of physical activity increased in PEG compared with PG (P = 0.04); however, no difference was observed between PEG and CG (P = 0.19) and between PG and CG (P = 0.26). For 300 min week-1, no difference was observed between groups. CONCLUSION: A school-based multi-component intervention including modification of the school environment was effective for increasing physical activity time among adolescents.

Prestroke Physical Activity and Adverse Health Outcomes After Stroke in the Atherosclerosis Risk in Communities Study.

BACKGROUND AND PURPOSE: The association of physical activity (PA) before stroke (prestroke PA) with long-term prognosis after stroke is still unclear. We examined the association of prestroke PA with adverse health outcomes in the ARIC study (Atherosclerosis Risk in Communities). METHODS: We included 881 participants with incident stroke occurring between 1993 and 1995 (visit 3) and December 31, 2016. Follow-up continued until December 31, 2017 to allow for at least 1-year after incident stroke. Prestroke PA was assessed using a modified version of the Baecke questionnaire in 1987 to 1989 (visit 1) and 1993 to 1995 (visit 3), evaluating PA domains (work, leisure, and sports) and total PA. We used Cox proportional hazards models to quantify the association between tertiles of accumulated prestroke PA levels over the 6-year period between visits 1 and 3 and mortality, risk of cardiovascular disease, and recurrent stroke after incident stroke. RESULTS: During a median follow-up of 3.1 years after incident stroke, 676 (77%) participants had adverse outcomes. Highest prestroke total PA was associated with decreased risks of all-cause mortality (hazard ratio, 0.78 [95% CI, 0.63-0.97]) compared with lowest tertile. In the analysis by domain-specific PA, highest levels of work PA were associated with lower risk for all-cause (hazard ratio, 0.77 [95% CI, 0.62-0.96]) and cardiovascular mortality (hazard ratio, 0.45 [95% CI, 0.29-0.70]), and highest levels of leisure PA were associated with lower all-cause mortality (hazard ratio, 0.72 [95% CI, 0.58-0.89]) compared with lowest tertile of PA. No significant associations for sports PA were observed. CONCLUSIONS: Higher levels of total prestroke PA as well as work and leisure PA were associated with lower risk of mortality after incident stroke. Public health strategies to increase lifetime PA should be encouraged to decrease long-term mortality after stroke.

Benznidazole decreases the risk of chronic Chagas disease progression and cardiovascular events: A long-term follow up study.

BACKGROUND: Chagas disease (CD) remains an important endemic disease in Latin America. However, CD became globalized in recent decades. The majority of the chronically infected individuals did not receive etiologic treatment for several reasons, among them the most conspicuous is the lack of access to diagnosis. The impact of trypanocidal treatment on CD chronic phase, without cardiac involvement (indeterminate form ICF), is yet to be determined. We aimed to evaluate the effect of trypanocidal treatment with benznidazole (BZN) on the rate of progression to Chagas heart disease in patients with ICF. METHODS: This is a retrospective cohort observational study including patients with ICF treated with BZN and compared to a group of non-treated patients matched for age, sex, region of origin, and the year of cohort entry. We reviewed the medical charts of all patients followed from May 1987 to June 2020 at the outpatient center of the Evandro Chagas National Institute of Infectious Diseases (INI) of the Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro, Brazil. Patients' follow-up included at least one annual medical visit and one annual electrocardiogram (ECG). Echocardiographic exams were performed at baseline and during the follow-up. Disease progression from ICF to cardiac form was defined by changes in baseline ECG. Cumulative incidence and the incidence rate were described in the incidence analysis. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals for the association between BZN and CD progression, cardiovascular events or death. FINDINGS: One hundred and fourteen treated patients met the study inclusion criteria. A comparison group of 114 non-treated patients matched for age, sex, region of origin, and the year of cohort entry was also included, totalizing 228 patients. Most patients included in the study were male (70.2%), and their mean age was 31.3 (+7.4) years. Over a median follow-up of 15.1 years (ranging from 1.0 to 32.4), the cumulative CD progression incidence in treated patients was 7.9% vs. 21.1% in the non-treated group (p = 0.04) and the CD progression rate was 0.49 per 1.000 patients/year in treated patients vs. 1.10 per 1.000 patients/year for non-treated patients (p = 0.02). BZN treatment was associated with a decreased risk of CD progression in both unadjusted (HR 0.46; 95%CI 0.21 to 0.98) and adjusted (HR 0.43; 95%CI 0.19 to 0.96) models and with a decreased risk of occurrence of the composite of cardiovascular events only in the adjusted (HR 0.15; 95%CI 0.03 to 0.80) model. No association was observed between BZN treatment and mortality. INTERPRETATION: In a long-term follow-up, BZN treatment was associated with a decreased incidence of CD progression from ICF to the cardiac form and also with a decreased risk of cardiovascular events. Therefore, our results indicate that BZN treatment for CD patients with ICF should be implemented into clinical practice.

Emerging concepts in metabolically healthy obesity.

Obesity is a major risk factor for noncommunicable diseases that is responsible for more than 70% of early deaths in the world. In the 1980's decade, some studies started to describe a "benign" obesity phenotype, named "metabolically healthy obesity" (MHO), which represents obesity without comorbidities such as hypertension, cardiovascular diseases, insulin resistance, diabetes, dyslipidemia or metabolic syndrome. However, it is still unclear if this "benign" obesity phenotype is really favorable or just a transition status to unhealthy obesity and if these subjects presented subclinical levels of cardiovascular risk that are not commonly detected. To further elucidate these issues, the investigation of pathophysiological mechanisms that can increase cardiovascular risk in MHO individuals, such as hormones and cytokines, may offer some responses. In parallel, the evaluation of subclinical cardiovascular derangement, using the systemic microcirculation as a proxy, may be an alternative to anticipate overt cardiovascular disease. Overall, further studies are needed to better understand the pathophysiology of MHO as well as to identify high-risk individuals who deserve more intensive management.

Transcutaneous Electrical Stimulation of PC5 and PC6 Acupoints Modulates Autonomic Balance in Heart Transplant Patients: A Pilot Study.

The increased resting heart rate (HR) in heart transplant patients is associated with enhanced metabolic demand, the potential for fatigue, and lower quality of life. In the present study, we hypothesized that transcutaneous electrical acupoint stimulation (TEAS) could modulate autonomic balance and reduce resting HR in these patients. A single-arm clinical trial was conducted with patients aged > 18 years, at ambulatorial accompaniment after heart transplantation, who were submitted to a single TEAS (40 minutes at pericardium channel acupoints PC5 and PC6). The arterial blood pressure and RR interval were recorded from 20 minutes before to 20 minutes after TEAS. The RR intervals were used to calculate HR variability (HRV) and the sympathovagal index. Linear mixed models were used for comparing variables before, during, and after TEAS. The significance level was set as P < 0.05. TEAS acutely improved HRV in transplant patients and enhanced the sympathovagal index during its application. Significant increases in systolic and diastolic blood pressure and mean arterial pressure were observed at recovery, such as a slight, but significant, decrease in HR. In conclusion, TEAS at PC5 and PC6 acutely modulates HRV and hemodynamics in transplant patients.

Influence of Baseline Physical Activity Level on Exercise Training Response and Clinical Outcomes in Heart Failure: The HF-ACTION Trial.

OBJECTIVES: This study sought to evaluate the influence of baseline physical activity (PA) on responses to aerobic exercise training and clinical events in outpatients with chronic systolic heart failure (HF) from the multicenter HF-ACTION (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure) trial. BACKGROUND: The influence of baseline PA on exercise capacity, responses to exercise training and clinical outcomes in patients with chronic HF is unclear. METHODS: Of 2,130 participants who provided consent for this analysis, 1,494 patients (64%) had complete baseline PA data, using a modified version of the International Physical Activity Questionnaire-Short Form questionnaire and were included in the analysis; 742 received usual care and 752 were allocated to the exercise training group. Changes in exercise capacity, all-cause mortality and hospitalization, cardiovascular (CV) mortality and hospitalization, and CV mortality and HF hospitalization were evaluated as a function of baseline PA tertile. RESULTS: At baseline, the highest PA tertile showed greater peak oxygen uptake, cardiopulmonary exercise test duration, and 6-min walk test distance than the other 2 PA tertiles, as well as lower New York Heart Association functional class, lower Beck depression score, and lower atrial fibrillation prevalence than the lowest PA tertile. Compared to the lowest PA tertile, the middle tertile had 18% lower risk of CV death/CV hospitalizations, and the upper tertile showed 23% lower risk of CV death/HF hospitalizations. Exercise capacity and clinical outcome responses to training were similar and largely nonsignificant across baseline PA tertiles with significant benefit of training on exercise test duration for all tertiles. CONCLUSIONS: In patients with chronic systolic HF, aerobic exercise training significantly improves exercise test duration to a similar extent across baseline PA tertiles. Although higher baseline PA was associated with lower risk of clinical events, no significant differences in event rates within each PA tertile were seen between subgroups randomized to exercise training versus usual care. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure [HF-ACTION]; NCT00047437).

Quality of life and associated factors in patients with chronic Chagas disease.

OBJECTIVES: To evaluate the quality of life (QoL) of patients with Chagas disease (CD) and the association between QoL domains and several clinical, socioeconomic and lifestyle characteristics of this population. METHODS: Cross-sectional observational study conducted from March 2014 to March 2017 including a total of 361 outpatients followed at Evandro Chagas National Institute of Infectious Disease, Brazil. QoL was assessed using the Portuguese shorter version of the original WHO Quality of Life questionnaire (WHOQOL-BREF). Information about clinical CD presentation, presence of comorbidities, functional class, previous benznidazole treatment, socioeconomic profile and lifestyle was also obtained. RESULTS: Environment and physical domains presented the worst QoL scores, while the social relationship domain presented the highest score. Multivariate regression analysis demonstrated that variables independently associated with QoL were functional class, sex, clinical presentation of CD, sleep duration, schooling, physical activity level, smoking, income per capita and residents by domicile. CONCLUSIONS: The low socioeconomic status and the physical limitations imposed by the disease presented an important impact on the QoL reduction among CD patients, especially on environment and physical domains. Strategies to improve QoL among CD patients should be tailored and consider many different variables to maximise improvements not only of patients' physical but also of their mental health.

Correlation of 6-min walk test with left ventricular function and quality of life in heart failure due to Chagas disease.

OBJECTIVES: To evaluate the correlation of the total distance walked during the six-minute walk test (6MWT) with left ventricular function and quality of life in patients with Chagas Disease (ChD) complicated by heart failure. METHODS: This is a cross-sectional study of adult patients with ChD and heart failure diagnosed based on Framingham criteria. 6MWT was performed following international guidelines. New York Heart Association functional class, brain natriuretic peptide (BNP) serum levels, echocardiographic parameters and quality of life (SF-36 and MLHFQ questionnaires) were determined and their correlation with the distance covered at the 6MWT was tested. RESULTS: Forty adult patients (19 male; 60 ± 12 years old) with ChD and heart failure were included in this study. The mean left ventricular ejection fraction was 35 ± 12%. Only two patients (5%) ceased walking before 6 min had elapsed. There were no cardiac events during the test. The average distance covered was 337 ± 105 metres. The distance covered presented a negative correlation with BNP (r = -0.37; P = 0.02), MLHFQ quality-of-life score (r = -0.54; P = 0.002), pulmonary artery systolic pressure (r = -0.42; P = 0.02) and the degree of diastolic dysfunction (r = -0.36; P = 0.03) and mitral regurgitation (r = -0.53; P = 0.0006) and positive correlation with several domains of the SF-36 questionnaire. CONCLUSIONS: The distance walked during the 6MWT correlates with BNP, quality of life and parameters of left ventricular diastolic function in ChD patients with heart failure. We propose this test to be adopted in endemic areas with limited resources to aid in the identification of patients who need referral for tertiary centres for further evaluation and treatment.