Coronary heart disease (CHD) is the most common cause of cardiovascular disease, which is the leading cause of death worldwide.1,2 Traditionally, CHD has been understood as a public health problem for men; thus, most of the evidence is based on male-based population studies. However, the prevalence of CHD is decreasing among men and is becoming an important chronic disease and major cause of death among women. The proportion of all deaths attributable to CHD is higher in women than in men, accounting for 49% of all deaths in women and 40% of all deaths in men in Europe.1 This trend will continue in the future because the life expectancy of women is higher than that of men, especially in developed countries. Consequently, the proportion of women with CHD will continue to grow and focus on older women.3
Women present with CHD approximately 10 years later than men do. A potential explanation is assumed to be a protective effect from estrogens before menopause.4,5 Men older than 65 years have double and women triple the risk of CHD occurrence compared with those younger than 65 years.6,7
Considering the chronic nature of CHD, adherence to secondary prevention measures is essential to prevent CHD progression and improve prognosis. In this study, adherence to treatment was conceptualized according to the Kyngäs theory of adherence of people with chronic disease, which emphasizes an active, intentional, and responsible process of care in which patients with CHD after percutaneous coronary intervention (PCI) work to maintain their health in collaboration with healthcare professionals.8 Adherence includes adherence to medication and to a healthy lifestyle, such as diet, physical activity, and smoking cessation, when applicable, as well as reduced alcohol consumption.8–11
Adherence to treatment, and in particular to a healthy lifestyle, of female patients with CHD after PCI is important—it is associated with a significantly decreased risk of CHD among women with high genetic risk.12 In addition, conventional CHD risk factors, such as smoking, hypertension, and dyslipidemia, have been found to be more harmful to women than to men regarding the development and progression of CHD. The accumulation of risk factors and an increasing prevalence of hypertension, obesity, and diabetes are more common in women than in men.12,13 Of concern is that women are often unaware of their risk for CHD.14 In addition, women have unique risk factors such as gestational diabetes and preeclampsia,15 which are related to a 2- to 3-fold risk of CHD in advanced-age women.15 Moreover, women diagnosed with CHD tend to have more comorbidities, including diabetes, atrial fibrillation, chronic kidney disease, peripheral arterial disease, and heart failure hypertension, at the time of the presentation of CHD compared with men.12,16
The issues related with CHD pathophysiology, prognosis, conventional risk factors, and medication have been thoroughly studied.17,18 In addition, the association between certain psychological factors and CHD has gained increased attention, especially in long-term chronic conditions where full recovery is unlikely.19 In particular, perceived health20 and social support21 have been points of interest. Perceived health describes patients' perceptions of their own health and health-related quality of life.20 Poor perceived health is an independent predictor for mortality22 and morbidity,23 as well as new cardiac events, for patients with CHD.24 Women perceive their health as worse20,25 and report anxiety and depression more often compared with men after PCI.26
Social support has been defined as a dynamic interpersonal process centered on the reciprocal exchange of information, which changes across contexts. Social support is manifested between providers and recipients; depending on its context, social support might seem multifaceted.27 Low social support reduces good prognoses among patients with CHD and is related with higher mortality in patients with CHD.21,28
Percutaneous coronary intervention as a revascularization method has become the treatment of choice for CHD compared with coronary artery bypass crafting in acute and elective care settings when it is medically possible and justified. Percutaneous coronary intervention leads to a more rapid recovery and short-term improvements in overall health status.29 However, worse outcomes, higher incidence of death, and several complications after PCI have been reported more often among women than men,30 and women have a higher mortality rate after primary PCI than men do.31
Because CHD in women has unique manifestations, it is important to identify how women adhere to secondary prevention recommendations and which factors are associated with adherence. In addition, knowledge of coronary risk factors is relatively poor in women,32 informational needs are different, and being a woman is a factor associated with nonparticipation in secondary prevention programs.33
Adherence to treatment among patients with CHD after PCI has been found to be associated with motivation, support from physicians and next of kin, informational support, results of care, perceived health, anxiety and depression, close relationships, alcohol consumption, previous PCI, the consumption of vegetables, physical activity, and gender (Figure 1).34
Evidence in respect to adherence to treatment of women with CHD after PCI is scant, yet adherence to treatment is a key factor regarding better prognosis of CHD. Therefore, the major objective of this study was to examine explanatory factors for adherence to treatment among women with CHD after PCI. This study is based on an earlier study of adherence to treatment34 with the aim of testing whether the empirical data from female patients with CHD after PCI would fit the proposed model of adherence to treatment after PCI (Figure 1). The specific hypothesis was that the model of adherence to treatment of patients with CHD after PCI is suitable for assessing adherence to treatment and associated factors among female patients.
This cross-sectional explanatory and descriptive substudy was part of a larger adherence study. Hospitalized adults aged 18 to 75 years with CHD were recruited from medical wards after PCI at 2 university hospitals and 3 central hospitals in Finland in 2013. The final response rate for the parent study was 80% (n = 416). Of this total population, 102 were women and are the subject of the current substudy. Both coronary angioplasty and coronary artery stenting procedure were included in the elective and acute settings. An exclusion criterion was a diagnosed memory disorder, for example, dementia or Alzheimer's disease.
Ethical approval to conduct this study was received (Kuopio University Hospital; ref. no. 2013-170). A registered nurse evaluated patients' suitability for participation based on the inclusion and exclusion criteria, provided verbal and written information about the study, and asked patients if they were willing to participate in the study during the patients' hospitalization. The survey was conducted by postal questionnaire 4 months after PCI.
The adherence to treatment of patient with chronic disease instrument is based on a theoretical model of chronically ill patients developed and tested by Kyngäs.9 This instrument includes 38 items measuring adherence to treatment. According to the original theory of adherence of people with chronic disease, adherence to treatment consisted of 2 mean sum variables: adherence to medication and a healthy lifestyle. These 2 variables were composed of 9 mean sum variables: responsibility, motivation, cooperation, results of care, fear of complications, sense of normality, support from next of kin, support from nurses, and support from physicians.5 Earlier studies have found the validity and reliability of the instrument high. Cronbach's α has ranged from .69 to .91.9–11,35 In addition, the adherence visual analogue scale instrument developed by Kähkönen et al,11 wherein the respondent evaluates his/her adherence to treatment on a scale from 0 (the worst imaginable adherence to treatment) to 100 (the best imaginable adherence to treatment), was also used to evaluate the level of adherence to treatment. Statistical details have been previously presented.34
The Social Support of People With Coronary Heart Disease (SSCHD) instrument36 was used to examine social support (informational, emotional, and functional support) among patients with CHD after PCI. The SSCHD instrument is based on the Cohen and Wills37 theory of social support. According to the theory, social support consists of 3 dimensions: informational, emotional and functional support.37 The dimension of informational support consists of items about respondents' perceived information regarding CHD, knowledge of their own risk factors, advice on risk factors, advice on what to do in case of chest pain, information on medications, advice on physical activity after PCI, and information on the continuum of care and cardiac rehabilitation. The dimension of emotional support includes items regarding respondents' perceived support from family, friends, and other cardiac patients and perceived importance to their next of kin. The items for the dimension of functional support are related to cooperation with healthcare professionals, opportunities to ask about issues of concern, and feeling supported and cared for. The construct validity of the instrument was verified with an explanatory factor analysis using principal axis factoring and Promax rotation. Three factors explained 59% of the total variance, communalities in all items were greater than 0.30, and the factor loadings of all variables varied between 0.34 and 0.86. Internal consistency of the mean sum variables was evaluated by Cronbach's α values and was .78, indicating an acceptable value.38 The complete SSCHD instrument has been previously presented.39
The EuroQoL 5-dimensional scale and EuroQoL visual analog scale were used to examine the perceived health of patients with CHD 4 months after PCI. The EuroQoL 5-dimensional scale and EuroQoL visual analog scale are widely used validated instruments; they consist of 5 items addressing 5 dimensions of health: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.36,40
Data were analyzed using the Statistical Package for Social Sciences (SPSS 24) software for Windows and Analysis of Moment Structures version 24. Descriptive statistics were used to describe the characteristics of the sample (means, standard deviations, ranges, and median). The compatibility of the theoretical model of adherence to treatment was tested among female patients using structural equation modeling, which is a suitable method for testing the relationship between the theoretical description and the concepts. The structural equation modeling software programs provide several statistical indices to evaluate the fit of the model. However, there is lack of consensus on the best indices. The goodness of fit and the correspondence between the theoretical model and observed correlation matrix in this study were tested with generally used modification indices: χ2 tests and their derivatives, Hoelter “critical N,” the root-mean-square error of approximation, Tucker-Lewis Index (TLI), and the comparative fit index were used. A sufficiently good model should have a comparative fit index of 0.90 and root-mean-square error of approximation 0.06 to 0.07. The standardized estimates were reported with correlations (standardized covariance) and path coefficients. The effect of standardized estimates is interpreted as weak if their values are less than 0.10. Estimates with a medium effect have values ~0.30, and estimates with a value greater than 0.50 are interpreted as having a major effect.41
Characteristics of the Participants
The sample in the present study consists of 102 female patients (Table) with CHD 4 months after PCI. The mean (SD) age of the female respondents was 65.1 (7.4) years (range, 42–75 years). Regarding health behavior, 13.7% were smokers, 52.9% used alcohol more than 2 portions per day, 14.7% engaged in 30 minutes of physical activity at least 3 times a week, and 19.8% consumed vegetables in their diet, eating at least the recommended 5 dL/d.
The mean (SD) value of adherence to treatment among female respondents was 87.2 (11.4) (range, 40.0–100.0), which was lower than adherence to treatment among the whole sample (87.8 [11.4]; range, 40–100). Although the difference in the level of adherence to treatment between the groups was not statistically significant, a different model explained perceived adherence to treatment among the female patients with CHD after PCI compared with the whole sample, in which both genders were represented (Figure 1).
To start, the original model of adherence to treatment was used with women's data using standardized regression weights (Figure 2). Direct positive associations between female respondents' adherence to treatment and motivation, support from physicians, and support from next of kin were tested. In addition, the indirect associations for female respondents' adherence to treatment—informational support, results of care and perceived health, anxiety and depression, marital status, alcohol consumption, previous PCI, gender, physical activity, and consumption of vegetables—were tested. In each step, error terms were specifically related to the items to depict prospective measuring error. In the first step, the outlined structural equation model with standardized estimates indicated an unacceptable model fit: χ2 = 1898.83, df = 933, P < .001, χ2/df = 1.94, TLI = 0.84, comparative fit index = 0.87, root-mean-square error of approximation = 0.34, indicating that the hypothesized model of adherence to treatment did not fit the empirical data from female respondents.42
In the next step, based on the standardized estimates, statistically insignificant variables were removed from the model one by one. In the definitive model analysis, a direct positive relationship was found between female respondents' adherence to treatment and motivation. The standardized path coefficient indicated a major effect (β = 0.7) in terms of direct association between motivation and women's adherence to treatment. Furthermore, informational support and support from physicians were indirectly, but significantly, associated with motivation. Additionally, physical activity and perceived health were associated with motivation. Physical activity was positively associated with anxiety and depression, which were negatively associated with perceived health. Indirect path coefficients indicated a medium effect (β = 0.2–0.4). The definitive structural equation model with standardized estimates indicated an acceptable model fit: χ2 = 888.59, df = 399, P < .001, χ2/df = 2.23, TLI = 0.90, comparative fit index = 0.91, root-mean-square error of approximation = 0. 40. In this model, the Hoelter critical N test rejected the null hypothesis. However, the model would be acceptable with up to 5% of risk, if n = 84.41
To the best of our knowledge, the present study is the first to test female post-PCI patient's adherence to treatment. Our findings indicated that female patients perceived their adherence to treatment to be high. However, there was a conflict between respondents' perceived adherence to treatment and the health behaviors they reported. Therefore, it is of paramount importance to focus on the issues that are known to contribute to women's adherence to treatment, rather than informational support or knowledge only.
In the present study, the strongest explanation for women's adherence to treatment was motivation, as has been the case in several previous studies related to adherence to treatment of chronically ill patients.8–11,34,35 A new finding from our study is that women's motivation for adherence was explained by support from physicians, informational support, assessment and counseling related to self-care for risk factors, identification of symptoms, medication, physical activity, follow-up treatment, and rehabilitation. Commonly, patients with CHD face the need to change multiple behaviors; therefore, identifying the behavior that is most important to the patient is a useful strategy.43 Although informational support has a mediation association to adherence via motivation, it is of paramount importance to include individual and patient-centered motivational elements, such as assessment, counseling, prescribed and supervised exercise training, risk factor control, and psychosocial support.44,45
Insufficient informational support as a form of counseling is a major reason for a reduced understanding of risk factors and the seriousness of CHD, which leads to reduced motivation for self-care.14 The motivational interviewing approach as a tool for professionals is a useful method for counseling and support for behavior change.42 Because the key factors that promote motivation are within nurses' scopes of practice, there is a need for appropriate training of nurses so that they can provide appropriate counseling using motivation promoting approaches. However, whereas the evidence of the benefits of motivational interviewing is strong, the evidence about the long-term effects on clinical and psychological outcomes is limited and further research is needed.43
Women's motivation to adhere to treatment was also explained by perceived health. According to the current view, perceived health is a strong predictor of long-term clinical outcomes in patients with CHD,19 which highlights the importance of including patients' subjective experiences of their perceived health as part of an overall strategy for enhancing clinical management to reduce the risk of adverse events.20
In this study, anxiety and depression were predictors of worse perceived health. Anxiety and depression are associated with increased risk for new cardiac events, poor prognosis and mortality,46 worse self-care, and worse functional capacity among patients with CHD.18,47 Thus, it is important to put effort into the identification of anxiety and depression among post-PCI patients.48 The results in this study confirmed the association between physical activity and anxiety and depression, which has been widely demonstrated previously: physical activity may alleviate depressive symptoms in patients with CHD and reduces mortality risk.48
In this study, support from nurses did not predict adherence to treatment directly. This emphasizes the importance of the therapeutic relationship between patients and physicians in the acute phase after PCI.49 Nurses' support in this study was provided through informational support. Direct support from nurses may be highlighted in follow-up care promoting secondary prevention, which is often arranged by nurses.
The present study has some methodological limitations. The cross-sectional design of the study may be a limitation because causality and generalizability cannot be assumed. The recruitment process is also a potential limitation because patients usually are discharged 24 hours after PCI. There is a risk that because of this rapid turnover, patients who met the inclusion criteria for the study were not included. Finally, in self-reported data collection methods, there is always a risk of the social desirability effect, in which patients provide answers they think are favorable instead of saying what they actually do or think.
Motivation was the strongest predictor of female patients' adherence to secondary prevention strategies after PCI. Female patients' adherence to treatment was not associated with close relationships or the support of next of kin. In addition, previous PCI or consumption of vegetables was not associated with adherence to treatment, and the role of support from physicians was different among female patients compared with the general model of adherence to treatment.34 Informational support, physician support, perceived health, and physical activity were indirectly, but significantly, associated with perceived adherence to treatment via motivation. These findings support the evidence that secondary prevention programs and patient education have to take into account individual or unique differences. It is important to pay attention to issues that are known to contribute to motivation rather than to reply on education alone to improve adherence.
What's New and Important
- Motivation, support from next of kin, and support from physicians are predictors for female patients' perceived adherence to treatment.
- Secondary prevention programs and patient education should take into account gender specific needs.
- It is important to emphasize physical activity as a part of secondary prevention because it associated with better perceived health and lower anxiety and depression.
We gratefully acknowledge the members of the PCICARE study group: M-L. Paananen, RN, and M. Kivi, RN, Central Finland Central Hospital; P. Jussila, RN, and I. Juntunen, RN, North Karelia Central Hospital; M. Lehtovirta, RN, and E. Pursiainen, RN, Päijät-Häme Central Hospital; A. Ruotsalainen, RN, and R-L. Heikkinen, RN, Kuopio University Hospital; and K. Peltomäki, RN, and V. Räsänen, Heart Hospital Tampere. We also acknowledge professor Pertti Töttö for statistical advice. In addition, we would like to thank nurses and all the patients who participated in the present study.
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