521926
research-article2014
CNU0010.1177/1474515114521926European Journal of Cardiovascular NursingChen et al.
EUROPEAN SOCIETY OF CARDIOLOGY ®
Original Article
Physical self-concept and its link to cardiopulmonary exercise tolerance among adolescents with mild congenital heart disease
European Journal of Cardiovascular Nursing 2015, Vol. 14(3) 206–213 © The European Society of Cardiology 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1474515114521926 cnu.sagepub.com
Chi-Wen Chen1, Wen-Jen Su2, Jou-Kou Wang3, Hsiao-Ling Yang4, Yueh-Tao Chiang5 and Philip Moons6
Abstract Background: Due to medical advances, most children with congenital heart disease (CHD) are expected to survive into adulthood. Establishing adequate physical self-concept and cardiopulmonary tolerance during the adolescent period can primarily enhance overall well-being. Aim: The purpose of this study was to undertake a gender-specific evaluation of the domain of physical self-concept among adolescents with mild CHD, and to examine the relationships between physical self-concept and cardiopulmonary exercise tolerance among adolescents with mild CHD. Methods: Four hundred and thirteen adolescents 12–20 years of age, whose cardiologists had not recommended any limitation of exercise, completed Physical Self-Description Questionnaires and three-minute step tests in two outpatient cardiology departments. Results: The male participants had significantly greater scores in measures of overall physical self-concept, competence in sports, physical appearance, body fat, physical activity, endurance, and strength than did the female participants. More than 80% of the participants had at least an average cardiopulmonary exercise tolerance index. The perception of not being ‘too fat’ and being more physically active were significant correlates of better cardiopulmonary exercise tolerance for adolescents with mild CHD. Conclusions: The results provided evidence for gender-specific evaluation of domains of physical self-concept among adolescents with mild CHD. The three-minute step test to measure cardiopulmonary exercise tolerance in adolescents with mild CHD may be an appropriate objective measure for use in future research. Continued efforts are needed in early intervention to promote cardiopulmonary exercise tolerance. Keywords Physical self-concept, cardiopulmonary tolerance, adolescents, congenital heart disease Date received: 23 October 2013; revised: 6 January 2014; accepted: 9 January 2014
Introduction
1Department
The birth prevalence of congenital heart disease (CHD) worldwide has been 9.1 per 1000 live births in the past 20 years.1 The highest reported total CHD birth prevalence is found in Asia (9.3 per 1000 live births).1 Significant advances in cardiac surgery and postoperative care have led to an almost 90% rate of survival into adulthood for affected individuals.2 Some adolescents have cardiac defects that may result in significant challenges in developing a positive self-image because of activity restrictions and altered
of Nursing, Fu-Jen Catholic University, Taiwan of Pediatric, Chang Gung Children’s Hospital, Taiwan 3Department of Pediatrics, National Taiwan University, Taiwan 4School of Nursing, National Taiwan University, Taiwan 5Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taiwan 6KU Leuven Department of Public Health and Primary Care, KU Leuven-University of Leuven, Belgium 2Department
Corresponding author: Chi-Wen Chen, Department of Nursing, Fu-Jen Catholic University, 510 Chung-Cheng Rd, Hsin-Chuan, New Taipei, 24205, Taiwan. Email: [email protected]
Downloaded from cnu.sagepub.com at UZH Hauptbibliothek / Zentralbibliothek Zürich on May 7, 2015
207
Chen et al. exercise capacity. However, little is known about their views on physical self-concept and how that relates to levels of cardiopulmonary exercise tolerance. Physical self-concept is considered to be a subdomain of the overall self-concept. This latter entity also entails family, school, and emotional self-concepts.3 The physical self-concept in itself is also multidimensional, and incorporates different characteristics, such as appearance, health, strength, body fat, and physical activity.4,5 This self-perception plays an important role in participation in physical activity 6,7 and physical fitness,8 especially during adolescence. Several studies have demonstrated sex differences in physical self-concept among children and adolescents;8–12 boys generally have higher scores than do girls, predominantly in subdomains, such as sport competence, strength, and endurance.8–12 This means that genderspecific approaches are required in the study of physical self-concept. Physical self-concept is an insufficiently studied aspect of CHD. To the best of our knowledge, few studies have explicitly investigated the patient’s physical self-concept.3,13 Not surprisingly, the physical selfconcept of school-aged children with CHD is significantly worse than that of children from the general population;3 however, the physical self-concept of adolescent boys with CHD is unexpectedly better than that of their healthy counterparts.13 It is, however, not known to what extent the physical self-concept stimulates or hampers adolescents with CHD in engagement in physical activity, and thus in maintaining physical fitness. One prior study concluded that of physical function was overestimated in adult patients when compared with actual exercise test results.14 If there is a relationship between the physical self-concept and exercise tolerance in adolescents with CHD, this could be a target for interventions, because the physical self-concept is a modifiable factor. In that case, interventions focusing on the physical selfconcept of patients could have an impact on the physical fitness throughout the patient’s life. This is particularly important for individuals in whom there are no medical reasons to restrict activity. Therefore, the present study aimed (a) to undertake a gender-specific evaluation of the physical self-concept among adolescents with mild CHD and (b) to examine the relationships between physical self-concept and cardiopulmonary exercise tolerance.
Methods Participant recruitment All patients with mild CHD treated in the pediatric cardiology outpatient departments of two medical centers in northern Taiwan in July–August, 2010, who met the inclusion and criteria, were approached to participate in
this study. Patients were eligible for inclusion if they were 12–20 years of age, and had been diagnosed with mild CHD. Mild CHD in this study was defined as ‘being able to exercise with no limits, and being in class I of the New York Heart Association classification’, as scored by cardiologists. The exclusion criteria were: chromosomal aberrations, extracardiac malformations, pregnancy, regular medication on diuretics, cardiotonics, angiotensinconverting enzyme inhibitor or beta-blockers, a pacemaker, an implantable cardioverter defibrillator (ICD), and hospitalization or cardiac catheterization within the last year.
Measures Physical self-concept was measured by the Physical SelfDescription Questionnaire (PSDQ).15 The PSDQ consists of a set of 54 items that assesses nine dimensions of sports competence, appearance, body fat, health, flexibility, physical activity, self-esteem, endurance, and strength. A six-point Likert scale was used, with responses ranging from ‘false’ to ‘true’. On this scale, 17 negatively worded items were scored inversely. Means were calculated for the total score and subscale scores, all ranging from 1–6, with a higher score representing a more positive self-concept. The psychometric properties of the PSDQ have been tested in diverse cultures.8,11,15–20 Internal consistency has been shown to be adequate with Cronbach’s alpha coefficient of internal consistency on the nine subscales ranging from 0.80–0.91.15 In the present study, Cronbach’s alpha ranged from 0.75 (health and strength) to 0.91 (sports competence and body fat) for the subscales, and was 0.94 for the total scale. The PSDQ’s validity has been established by its significant relationship to components of physical fitness8,19,21 and other self-concept instruments.5,11 In the present study, we measured cardiopulmonary exercise tolerance using a three-minute step test, which is also known as the Harvard Step Test. It is an easy and inexpensive method to screen for cardiopulmonary fitness and an individual’s ability to recover after strenuous exercise. For its use in young Asian persons, we followed the standard procedure as described by the Sports Affairs Council in Taiwan.22 A 35 cm (13.8 inch) step was used. A metronome was set at a rate of 96 beats per min to control the frequencies of stepping up and down. Immediately after the Harvard Step Test, the heart rate (HR) of each individual was measured by a finger sensor between 1–1.5 min (HR1), 2–2.5 min (HR2), and 3–3.5 min (HR3). The cardiopulmonary exercise tolerance index was calculated as follows: duration of test (s)×100/(HR1+HR2+HR3)×2.22 The higher the score the better the cardiopulmonary exercise tolerance of the subjects because the score reflects the speed of recovery from the physical activity. Prior research has demonstrated that the three-minute step test has acceptable reliability, validity, and objectivity for predicting the
Downloaded from cnu.sagepub.com at UZH Hauptbibliothek / Zentralbibliothek Zürich on May 7, 2015
208
European Journal of Cardiovascular Nursing 14(3)
cardiopulmonary exercise tolerance of a large population.23,24 In addition, this step test seems to be more appropriate for female, youth, or vulnerable populations.25 In the present study, we compared the cardiopulmonary exercise tolerance index of each subject with norm-based cut-off scores from the Sports Affairs Council in Taiwan, based on their gender and age. This allowed us to categorize our patients into five classes of cardiopulmonary exercise tolerance: very poor, poor, average, good, and very good levels.
Procedure This study was approved by the institutional review boards of the two hospitals, and written informed consent was obtained from the adolescents and their guardians. After completing the demographic form and PSDQ, which required about 15 min, the subjects underwent a step test in a separate clinic room. In order to monitor the intensity of exercise, each subject wore a pulse-oximetry monitor on his/her wrist during the test. In accordance with the recommendations of the Health Promotion Administration, Ministry of Health and Welfare in Taiwan, 60–85% of maximum predicted heart rate (220–age) was defined as the optimal exercise range. The subjects were instructed to quit this test at any time if their heart rate exceeded 170 beat/min, and O2 saturation fell below 95%.26 Supplemental oxygen and an Ambu bag were readily available in case of emergency.
Data analysis Data were analyzed using SPSS version 20.0 (SPSS Inc., Chicago, Illinois, USA). Descriptive statistics for all key variables were calculated. The Mann-Whitney test was used to compare the differences in age and body mass index (BMI) between female and male participants. Chisquare tests were used to compare the differences in diagnosis, number of heart operations, and level of participation in physical education between female and male participants. To analyze the gender differences in physical self-concept and cardiopulmonary exercise tolerance, we performed multiple regression analysis, with adjustments for age, diagnosis, and number of heart operations. Furthermore, a hierarchical multivariable linear regression analysis (enter method) was conducted to investigate the relationship between the physical selfconcept and cardiopulmonary exercise tolerance index, adjusted for gender, age, diagnosis, and number of heart operations. In this analysis, gender, age, diagnosis, and number of heart operations were entered in block 1, and the subscale scores of self-concept were entered in block 2. The assumptions of normality and multicollinearity were met. All tests were two-sided, and the level of significance was set at p
research-article2014
CNU0010.1177/1474515114521926European Journal of Cardiovascular NursingChen et al.
EUROPEAN SOCIETY OF CARDIOLOGY ®
Original Article
Physical self-concept and its link to cardiopulmonary exercise tolerance among adolescents with mild congenital heart disease
European Journal of Cardiovascular Nursing 2015, Vol. 14(3) 206–213 © The European Society of Cardiology 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1474515114521926 cnu.sagepub.com
Chi-Wen Chen1, Wen-Jen Su2, Jou-Kou Wang3, Hsiao-Ling Yang4, Yueh-Tao Chiang5 and Philip Moons6
Abstract Background: Due to medical advances, most children with congenital heart disease (CHD) are expected to survive into adulthood. Establishing adequate physical self-concept and cardiopulmonary tolerance during the adolescent period can primarily enhance overall well-being. Aim: The purpose of this study was to undertake a gender-specific evaluation of the domain of physical self-concept among adolescents with mild CHD, and to examine the relationships between physical self-concept and cardiopulmonary exercise tolerance among adolescents with mild CHD. Methods: Four hundred and thirteen adolescents 12–20 years of age, whose cardiologists had not recommended any limitation of exercise, completed Physical Self-Description Questionnaires and three-minute step tests in two outpatient cardiology departments. Results: The male participants had significantly greater scores in measures of overall physical self-concept, competence in sports, physical appearance, body fat, physical activity, endurance, and strength than did the female participants. More than 80% of the participants had at least an average cardiopulmonary exercise tolerance index. The perception of not being ‘too fat’ and being more physically active were significant correlates of better cardiopulmonary exercise tolerance for adolescents with mild CHD. Conclusions: The results provided evidence for gender-specific evaluation of domains of physical self-concept among adolescents with mild CHD. The three-minute step test to measure cardiopulmonary exercise tolerance in adolescents with mild CHD may be an appropriate objective measure for use in future research. Continued efforts are needed in early intervention to promote cardiopulmonary exercise tolerance. Keywords Physical self-concept, cardiopulmonary tolerance, adolescents, congenital heart disease Date received: 23 October 2013; revised: 6 January 2014; accepted: 9 January 2014
Introduction
1Department
The birth prevalence of congenital heart disease (CHD) worldwide has been 9.1 per 1000 live births in the past 20 years.1 The highest reported total CHD birth prevalence is found in Asia (9.3 per 1000 live births).1 Significant advances in cardiac surgery and postoperative care have led to an almost 90% rate of survival into adulthood for affected individuals.2 Some adolescents have cardiac defects that may result in significant challenges in developing a positive self-image because of activity restrictions and altered
of Nursing, Fu-Jen Catholic University, Taiwan of Pediatric, Chang Gung Children’s Hospital, Taiwan 3Department of Pediatrics, National Taiwan University, Taiwan 4School of Nursing, National Taiwan University, Taiwan 5Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taiwan 6KU Leuven Department of Public Health and Primary Care, KU Leuven-University of Leuven, Belgium 2Department
Corresponding author: Chi-Wen Chen, Department of Nursing, Fu-Jen Catholic University, 510 Chung-Cheng Rd, Hsin-Chuan, New Taipei, 24205, Taiwan. Email: [email protected]
Downloaded from cnu.sagepub.com at UZH Hauptbibliothek / Zentralbibliothek Zürich on May 7, 2015
207
Chen et al. exercise capacity. However, little is known about their views on physical self-concept and how that relates to levels of cardiopulmonary exercise tolerance. Physical self-concept is considered to be a subdomain of the overall self-concept. This latter entity also entails family, school, and emotional self-concepts.3 The physical self-concept in itself is also multidimensional, and incorporates different characteristics, such as appearance, health, strength, body fat, and physical activity.4,5 This self-perception plays an important role in participation in physical activity 6,7 and physical fitness,8 especially during adolescence. Several studies have demonstrated sex differences in physical self-concept among children and adolescents;8–12 boys generally have higher scores than do girls, predominantly in subdomains, such as sport competence, strength, and endurance.8–12 This means that genderspecific approaches are required in the study of physical self-concept. Physical self-concept is an insufficiently studied aspect of CHD. To the best of our knowledge, few studies have explicitly investigated the patient’s physical self-concept.3,13 Not surprisingly, the physical selfconcept of school-aged children with CHD is significantly worse than that of children from the general population;3 however, the physical self-concept of adolescent boys with CHD is unexpectedly better than that of their healthy counterparts.13 It is, however, not known to what extent the physical self-concept stimulates or hampers adolescents with CHD in engagement in physical activity, and thus in maintaining physical fitness. One prior study concluded that of physical function was overestimated in adult patients when compared with actual exercise test results.14 If there is a relationship between the physical self-concept and exercise tolerance in adolescents with CHD, this could be a target for interventions, because the physical self-concept is a modifiable factor. In that case, interventions focusing on the physical selfconcept of patients could have an impact on the physical fitness throughout the patient’s life. This is particularly important for individuals in whom there are no medical reasons to restrict activity. Therefore, the present study aimed (a) to undertake a gender-specific evaluation of the physical self-concept among adolescents with mild CHD and (b) to examine the relationships between physical self-concept and cardiopulmonary exercise tolerance.
Methods Participant recruitment All patients with mild CHD treated in the pediatric cardiology outpatient departments of two medical centers in northern Taiwan in July–August, 2010, who met the inclusion and criteria, were approached to participate in
this study. Patients were eligible for inclusion if they were 12–20 years of age, and had been diagnosed with mild CHD. Mild CHD in this study was defined as ‘being able to exercise with no limits, and being in class I of the New York Heart Association classification’, as scored by cardiologists. The exclusion criteria were: chromosomal aberrations, extracardiac malformations, pregnancy, regular medication on diuretics, cardiotonics, angiotensinconverting enzyme inhibitor or beta-blockers, a pacemaker, an implantable cardioverter defibrillator (ICD), and hospitalization or cardiac catheterization within the last year.
Measures Physical self-concept was measured by the Physical SelfDescription Questionnaire (PSDQ).15 The PSDQ consists of a set of 54 items that assesses nine dimensions of sports competence, appearance, body fat, health, flexibility, physical activity, self-esteem, endurance, and strength. A six-point Likert scale was used, with responses ranging from ‘false’ to ‘true’. On this scale, 17 negatively worded items were scored inversely. Means were calculated for the total score and subscale scores, all ranging from 1–6, with a higher score representing a more positive self-concept. The psychometric properties of the PSDQ have been tested in diverse cultures.8,11,15–20 Internal consistency has been shown to be adequate with Cronbach’s alpha coefficient of internal consistency on the nine subscales ranging from 0.80–0.91.15 In the present study, Cronbach’s alpha ranged from 0.75 (health and strength) to 0.91 (sports competence and body fat) for the subscales, and was 0.94 for the total scale. The PSDQ’s validity has been established by its significant relationship to components of physical fitness8,19,21 and other self-concept instruments.5,11 In the present study, we measured cardiopulmonary exercise tolerance using a three-minute step test, which is also known as the Harvard Step Test. It is an easy and inexpensive method to screen for cardiopulmonary fitness and an individual’s ability to recover after strenuous exercise. For its use in young Asian persons, we followed the standard procedure as described by the Sports Affairs Council in Taiwan.22 A 35 cm (13.8 inch) step was used. A metronome was set at a rate of 96 beats per min to control the frequencies of stepping up and down. Immediately after the Harvard Step Test, the heart rate (HR) of each individual was measured by a finger sensor between 1–1.5 min (HR1), 2–2.5 min (HR2), and 3–3.5 min (HR3). The cardiopulmonary exercise tolerance index was calculated as follows: duration of test (s)×100/(HR1+HR2+HR3)×2.22 The higher the score the better the cardiopulmonary exercise tolerance of the subjects because the score reflects the speed of recovery from the physical activity. Prior research has demonstrated that the three-minute step test has acceptable reliability, validity, and objectivity for predicting the
Downloaded from cnu.sagepub.com at UZH Hauptbibliothek / Zentralbibliothek Zürich on May 7, 2015
208
European Journal of Cardiovascular Nursing 14(3)
cardiopulmonary exercise tolerance of a large population.23,24 In addition, this step test seems to be more appropriate for female, youth, or vulnerable populations.25 In the present study, we compared the cardiopulmonary exercise tolerance index of each subject with norm-based cut-off scores from the Sports Affairs Council in Taiwan, based on their gender and age. This allowed us to categorize our patients into five classes of cardiopulmonary exercise tolerance: very poor, poor, average, good, and very good levels.
Procedure This study was approved by the institutional review boards of the two hospitals, and written informed consent was obtained from the adolescents and their guardians. After completing the demographic form and PSDQ, which required about 15 min, the subjects underwent a step test in a separate clinic room. In order to monitor the intensity of exercise, each subject wore a pulse-oximetry monitor on his/her wrist during the test. In accordance with the recommendations of the Health Promotion Administration, Ministry of Health and Welfare in Taiwan, 60–85% of maximum predicted heart rate (220–age) was defined as the optimal exercise range. The subjects were instructed to quit this test at any time if their heart rate exceeded 170 beat/min, and O2 saturation fell below 95%.26 Supplemental oxygen and an Ambu bag were readily available in case of emergency.
Data analysis Data were analyzed using SPSS version 20.0 (SPSS Inc., Chicago, Illinois, USA). Descriptive statistics for all key variables were calculated. The Mann-Whitney test was used to compare the differences in age and body mass index (BMI) between female and male participants. Chisquare tests were used to compare the differences in diagnosis, number of heart operations, and level of participation in physical education between female and male participants. To analyze the gender differences in physical self-concept and cardiopulmonary exercise tolerance, we performed multiple regression analysis, with adjustments for age, diagnosis, and number of heart operations. Furthermore, a hierarchical multivariable linear regression analysis (enter method) was conducted to investigate the relationship between the physical selfconcept and cardiopulmonary exercise tolerance index, adjusted for gender, age, diagnosis, and number of heart operations. In this analysis, gender, age, diagnosis, and number of heart operations were entered in block 1, and the subscale scores of self-concept were entered in block 2. The assumptions of normality and multicollinearity were met. All tests were two-sided, and the level of significance was set at p
