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In patients with cardiovascular disease (CVD), knowledge about the associations among changes in depressive symptoms, self-efficacy, and self-care activities has been requested. This is because such knowledge can be helpful in the design of behavioral interventions aimed to improve self-efficacy, reduce depressive symptoms, and improve performance of self-care activities in CVD patients.
We aim to evaluate if internet-based cognitive behavioral therapy (iCBT) improves self-efficacy and explore the relationships among changes in depressive symptoms, self-efficacy, and physical activity, as well as the influence of iCBT on these relationships.
This study received funding in January 2015. Participant recruitment took place between January 2017 and February 2018, and the main findings were published in 2019. This study is a secondary analysis of data collected in a randomized controlled study evaluating the effects of a 9-week iCBT program compared to an online discussion forum (ODF) on depressive symptoms in patients with CVD (N=144). Data were collected at baseline and at the 9-week follow-up. Analysis of covariance was used to evaluate the differences in self-efficacy between the iCBT and ODF groups. Structural equation modeling explored the relationships among changes in depressive symptoms, self-efficacy, and physical activity, as well as the influence of iCBT on these relationships.
At follow-up, a significant difference in the increase in self-efficacy favoring iCBT was found (
Self-efficacy was improved by iCBT. However, the influence of iCBT on self-efficacy and physical activity was mostly mediated by improvements in depressive symptoms.
ClinicalTrials.gov NCT02778074; https://clinicaltrials.gov/ct2/show/NCT02778074
Depression is a serious health problem in patients with cardiovascular disease (CVD) (ie, atrial fibrillation/atrial flutter, ischemic heart disease, and heart failure). It is estimated that 20% to 40% of CVD patients experience depressive symptoms, leading to reduced health-related quality of life and increased risk of worse cardiovascular outcomes [
One possible mechanism behind these negative effects is that depressive symptoms are associated with biological changes such as overactivation of the sympathetic drive, chronic activation of the hypothalamic-pituitary-axis (HPA), and increased inflammation, all of which contribute to atherosclerosis, myocardial injury, and cell death [
Self-efficacy has an important role in the performance of adequate self-care behaviors [
In a previous randomized controlled trial (RCT), we have reported that 9 weeks of internet-based cognitive behavioral therapy (iCBT) led to significantly lower levels of depressive symptoms compared to an online discussion forum (ODF) at the 9-week follow-up (–2.34, 95% CI –3.58 to –1.10,
This study received funding in January 2015 (trial registration NCT02778074) . Participant recruitment took place between January 2017 and February 2018, and the main findings were published in 2019 [
The regional ethical review board of Linköping in Sweden approved the study (reference number 2016/72-31).
Data for this analysis were collected at baseline and at follow-up at the end of the 9-week intervention period. All data were collected through questionnaires on the study website [
Self-efficacy was measured using the Swedish version of the General Self-efficacy Scale (GSES) [
The Montgomery Åsberg Depression Rating Scale (self-rating version) (MADRS-S) was used to measure depressive symptoms. This instrument consists of 9 items rated on a 7-point scale with a maximum score of 54. Scores 13-19, 20-34, and >35 indicate mild, moderate, and severe depression, respectively [
The frequency and length of physical activity were measured using 2 modified items from the Physical Activity Questionnaire [
Descriptive statistics was used to describe the study population. Continuous variables were described as means and SDs, and categorical variables were described as numbers and percentages. All analyses were performed on original data, thus including participants with complete data at the 9-week follow-up (n=127). Analysis of covariance was used to evaluate if there was a significant difference in self-efficacy scores at the 9-week follow-up between the iCBT and ODF groups after adjustment for self-efficacy scores at baseline. The Cohen
The mean age of the study population was 63 years. Among the 144 participants, 90 (62%) were males; almost 29 (20%) lived alone, and another 29 participants (20)% described their financial situation as problematic. Few participants were current smokers (ie, 4/144, 3%) or drank more than 10 units of alcohol per week (ie, 7/144, 5%). The median number of medications was 5 and approximately 48 participants had more than 1 comorbidity.
Description of the study population at baseline.
Characteristics | Total N=144 | iCBTa (n=72) | ODFb (n=72) | ||||||
Age in years, mean (SD) | 63 (12) | 61 (13) | 64 (11) | .12 | |||||
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.39 | ||||||||
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Male | 89 (62) | 47 (65) | 42 (58) |
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Female | 55 (38) | 25 (35) | 30 (42) |
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Living alone, n (%) | 28 (19) | 13 (18) | 15 (21) | .67 | |||||
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.31 | ||||||||
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Elementary | 19 (13) | 7 (10) | 12 (17) |
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Upper secondary/high school | 37 (26) | 16 (22) | 21 (29) |
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Postsecondary education/college/university< 2 years | 35 (24) | 21 (29) | 14 (19) |
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University≥2 years | 53 (37) | 28 (39) | 25 (35) |
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|||||||||
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.75 | |||||||
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Never | 69 (48) | 33 (46) | 36 (50) |
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Ex-smoker | 70 (49) | 35 (51) | 33 (46) |
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Smoker | 5 (3) | 2 (3) | 3 (4) |
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.32 | |||||||
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≤4 units/week | 109 (76) | 51 (71) | 58 (81) |
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5-9 units/week | 27 (19) | 17 (24) | 10 (14) |
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≥10 units/week | 8 (5) | 4 (5) | 4 (5) |
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Myocardial infarction/angina | 49 (34) | 34 (47) | 29 (40) | .4 | ||||
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Atrial fibrillation | 65 (45) | 40 (56) | 41 (57) | .86 | ||||
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Heart failure | 30 (21) | 18 (25) | 20 (28) | .70 | ||||
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>1 diagnosis | 40 (28) | 20 (28) | 20 (28) | .73 | ||||
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I | 41 (28) | 23 (32) | 18 (25) |
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II | 53 (37) | 25 (35) | 28 (39) |
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III | 50 (35) | 26 (33) | 26 (36) |
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Antidepressants, n (%) | 20 (14) | 7 (10) | 13 (18) | .15 | ||||
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Antiplatelets/anticoagulants, n (%) | 128 (88) | 63 (88) | 65 (90) | >.99 | ||||
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Beta-blockers, n (%) | 110 (76) | 55 (76) | 55 (76) | >.99 | ||||
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Diuretics, n (%) | 33 (23) |
14 (19) |
19 (26) |
.32 |
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Mineral receptor antagonists, n (%) | 15 (8) |
5 (7) |
6 (8) |
.75 |
||||
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Nitroglycerine, n (%) |
30 (21) |
15 (21) |
15 (21) |
>.99 |
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RAASc blockade, n (%) |
69 (48) |
34 (47) |
35 (49) |
.86 |
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Statins, n (%) |
69 (48) |
36 (50) |
33 (46) |
.62 |
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Number of medications, median (IQR) | 5 (4-6) | 5 (4-6) | 5 (4-6) | .72 | ||||
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Hypertension |
76 (53) |
36 (50) |
40 (56) |
.5 | ||||
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Diabetes |
21 (15) |
8 (11) |
13 (18) |
.24 |
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Pulmonary disease | 15 (10) |
7 (10) |
8 (11) |
.78 |
||||
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Transischemic attack/stroke |
19 (13) |
9 (12) |
10 (14) |
.81 |
||||
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Cancer |
16 (11) |
7 (10) |
9 (12) |
.6 | ||||
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>1 comorbidity | 39 (27) | 17 (24) | 22 (31) | .35 | ||||
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MADRS-Sd | 17.8 (6.7) | 18 (7.2) | 17.7 (6.2) | .31 | ||||
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General Self-efficacy Scale | 27.2 (6.3) | 27.0 (6.3) | 27.4 (6.3) | .9 | ||||
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Physical activity factor | 4.8 (3.5) | 5.0 (3.7) | 4.7 (3.4) | .7 |
aiCBT: internet-based cognitive behavioral therapy.
bODF: online discussion forum.
cRAAS: renin-angiotensin-aldosterone system.
dMADRS-S: Montgomery Åsberg Depression Rating Scale (self-rating version)
At the 9-week follow-up, the mean self-efficacy scores and SD values for the iCBT group and the ODF group were 29.9 (5.8) and 28.2 (6.4), respectively. After adjustment for baseline scores, analysis of covariance showed a significant difference in the increase of self-efficacy in favor of iCBT (1.67,
For analyzing the associations among the changes in self-efficacy, depressive symptoms, and physical activity, we first explored an SEM model based on the mediation model reported by Maeda et al [
However, the findings reported by Maeda et al [
Furthermore, adding iCBT to our simplex model (
Performance accomplishment has been discussed as an important precursor of self-efficacy; if a person is successful at tasks, the feeling of efficacy will increase [
Model of the associations between changes in depressive symptoms, physical activity and self-efficacy based on the model by Maeda et al [
Simplex model describing the associations between changes in depressive symptoms, self-efficacy and physical activity. The model states that a change in depressive symptoms leads to a change in self-efficacy, which in turn leads to a change in physical activity. The thin grey dotted line indicates a significant indirect association between a change in depressive symptoms and a change in physical activity mediated by a change in self-efficacy. The associations in the model are described with the standardized coefficients (
Summary of the simplex model exploring the associations among changes in depressive symptoms, self-efficacy, and physical activity using the standardized coefficients (
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Change in depressive symptoms | Change in self-efficacy | |
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–.64 | —a |
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<.001 | — | |
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–.31 | .49 |
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<.001 | .01 |
aNot applicable.
Simplex model describing the associations among changes in depressive symptoms, self-efficacy, and physical activity as a function of iCBT. The dotted lines indicate significant and indirect associations between iCBT and changes in self-efficacy and physical activity as well as between the changes in depressive symptom and physical activity. The associations in the model are described with the standardized coefficients (
Summary of the simplex model exploring the association of internet-based cognitive behavioral therapy with the changes in depressive symptoms, self-efficacy, and physical activity using the standardized coefficients (
|
Internet cognitive behavior therapy |
Change in depressive symptoms | Change in self-efficacy | |
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.37 | —a | — |
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<.001 | — | — | |
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–.23 | –.63 | — |
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<.001 | .001 | — | |
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–.12 | –.32 | .5 |
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<.03 | <.001 | .01 |
aNot applicable.
The main findings of this study were that iCBT improved self-efficacy. However, the influence of iCBT on the improvement in self-efficacy and physical activity was mediated by improvements in depressive symptoms. Thus, self-efficacy was a mediator between improvements in depressive symptoms and physical activity.
In this study, we investigated the influence of self-efficacy on the changes in depressive symptoms and self-care through physical activity (ie, an aspect of autonomous self-care) [
However, for such improvements to take place, an intervention is most likely needed. There have been requests for behavioral interventions that promote improvement of depressive symptoms, self-efficacy, and self-care in CVD patients [
Most digital interventional studies in cardiac rehabilitation focus on physical activity and counseling, with less focus on the core components such as psychological management [
A limitation of this study is that this was a secondary analysis of data, and it did not primarily intend to investigate the effect of iCBT on self-efficacy or to explore the associations among changes in depressive symptoms, self-efficacy, and physical activity. Furthermore, data regarding physical activity were collected using only self-reports and not through objective measurements. This may have underestimated the level of physical activity measured [
The iCBT program was more effective than the ODF in increasing self-efficacy in CVD patients. An increase in self-efficacy was the mediator between improvements in depressive symptoms and physical activity. Improvements in depressive symptoms mediated most of the influence of iCBT on the improvements in self-efficacy and physical activity. The findings are preliminary and replication in larger samples is needed.
cardiovascular disease
comparative fit index
General Self-efficacy Scale
hypothalamic-pituitary-axis
internet-based cognitive behavioral therapy
Montgomery Åsberg Depression Rating Scale
online discussion forum
randomized controlled trial
root mean square error of approximation
structural equation modeling
This study received funding from the Swedish Research Council (grant 2015-02600), ALF grants from the Region Östergötland (grants LIO-600321 and LIO-687531), and Strategic fund from the Region Östergötland (grant LIO-719561). The funders of the study had no role in the study design, in the collection, analysis, and interpretation of the data, or in the writing of the manuscript. PJ and JL had full access to all the study data. All authors have approved the manuscript for publication.
PJ, GA, ES, GM, and JL designed the study. PJ, GA, GM, and JL performed the study and obtained data. PJ and ES performed statistical analyses. PJ, GA, ES, GM, and JL interpreted the data. PJ, GA, ES, GM, and JL drafted the paper.
None declared.