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Changes in Heart Failure Symptoms are Associated With Changes in Health-related Quality of Life Over 12 Months in Patients With Heart Failure

Heo, Seongkum, PhD, RN; Moser, Debra K., PhD, RN, FAAN; Lennie, Terry A., PhD, RN; Fischer, Mary, MSN, RN; Kim, JinShil, PhD, RN; Lee, Mikyoung, PhD, RN; Walsh, Mary N., MD; Ounpraseuth, Songthip, PhD

doi: 10.1097/JCN.0000000000000493
ARTICLES: Heart Failure

Purpose: Patients with heart failure (HF) have notably poor health-related quality of life (HRQOL). A 5-point improvement in HRQOL is associated with reduction in hospitalization and mortality rates. Heart failure symptoms are associated with poor HRQOL, but little is known about whether changes in HF symptoms lead to changes in HRQOL over time. Therefore, we examined the association of changes in HF symptoms with changes in overall, physical, and emotional aspects of HRQOL over a 12-month period, controlling for typical covariates.

Methods: Data on HF symptoms and HRQOL (Minnesota Living Heart Failure questionnaire) were collected from 94 patients with HF (mean age, 58 years; 58.5% female) at baseline and 12-month follow-up. Psychosocial factors (depressive symptoms, perceived control, and social support), behavioral factors (medication adherence and sodium intake), sociodemographic and clinical factors (age, comorbidities, and body mass index), and a physical factor (functional status) were collected at baseline. Multiple and logistic regression analyses were used to analyze the data.

Results: In complete models, changes in HF symptoms were associated with changes in the total HRQOL (P < .001) and the physical (P < .001) and emotional (P < .001) aspects of HRQOL over 12 months, controlling for all the factors. Changes in HF symptoms were significantly associated with the likelihood of at least a 5-point improvement in HRQOL (P = .001), controlling for covariates.

Conclusions: Improvement in HF symptoms was associated with improvement in HRQOL over 12 months. Thus, development and delivery of interventions that target improvement in HF symptoms may improve HRQOL.

Seongkum Heo, PhD, RN Associate Professor, College of Nursing, University of Arkansas for Medical Sciences, Little Rock.

Debra K. Moser, PhD, RN, FAAN Professor, College of Nursing, University of Kentucky, Lexington.

Terry A. Lennie, PhD, RN Professor, College of Nursing, University of Kentucky, Lexington.

Mary Fischer, MSN, RN Clinical Nurse Specialist, St Vincent Hospital, Indianapolis, IN.

JinShil Kim, PhD, RN Professor, College of Nursing, Gachon University, Incheon, South Korea.

Mikyoung Lee, PhD, RN Associate Professor, College of Nursing, Texas Woman’s University, Denton.

Mary N. Walsh, MD Cardiologist, St Vincent Hospital, Indianapolis, IN.

Songthip Ounpraseuth, PhD College of Public Health, University of Arkansas for Medical Sciences, Little Rock.

The article was edited by the Office of Grants and Scientific Publications at the University of Arkansas for Medical Sciences.

Funding for this study came from the American Heart Association, Scientific Development Grant (0830104N) to S.H.

The authors have no conflicts of interest to disclose.

Correspondence Seongkum Heo, PhD, RN, College of Nursing, University of Arkansas for Medical Sciences, 4301 W Markham St, Slot #529, Little Rock, AR 72205 (sheo@uams.edu).

Health-related quality of life (HRQOL) is a multidimensional concept with a variety of dimensions, such as physical, emotional, and socioeconomic.1 Patients with heart failure (HF) have poor HRQOL assessed by both generic and disease-specific instruments.2,3 This may be due to the nature of HF, which is an incurable condition with an uncertain, but downward, debilitating trajectory.4–6 Short- and long-term changes in HRQOL have been associated with hospitalization and mortality rates.7,8 For example, improvements in HRQOL at 3 and 6 months are associated with lower risks for hospitalization or mortality.8 An improvement of at least 5 in the score of the Minnesota Living with Heart Failure Questionnaire (MLHFQ; reflecting improvement in HRQOL) 1 month after hospital discharge is associated with a lower risk for hospitalization or mortality.7 Therefore, it is necessary to identify factors that could be associated with changes in HRQOL to improve HRQOL and reduce hospitalization and mortality rates for patients with HF.

Factors associated with improvements in HRQOL, especially long-term changes in HRQOL, using longitudinal study designs have been rarely examined in patients with HF. In 1 longitudinal study,9 both baseline HF and depressive symptoms showed dose-dependent relationships to HRQOL at 12 months, but other variables were not considered. A theoretical model of factors associated with HRQOL from patients’ perspectives1 and cross-sectional studies show multidimensional factors that have been commonly associated with HRQOL (Figure).8,10–14 In cross-sectional studies, sociodemographic and clinical characteristics, such as older age, fewer comorbidities, and a lower body mass index, have been associated with better HRQOL.8,10,11 Better psychosocial status, such as less severe depressive symptoms, higher levels of perceived control, and higher levels of perceived social support, is also commonly associated with better HRQOL in cross-sectional HF studies.12,13 Better behavioral status, such as better self-care, is associated with better HRQOL in a cross-sectional HF study,1 although changes in self-care within individual patients with HF are not associated with HRQOL at 6 months.15 Better physical status, such as lower New York Heart Association (NYHA) functional classes and less severe HF symptoms, is consistently associated with better HRQOL.8,11,14,16 Thus, the relationships of these factors and HRQOL have been established in patients with HF. In addition, those factors are related to each other. Sociodemographic and clinical factors (eg, comorbidities) are associated with physical and psychosocial factors (eg, HF and depressive symptoms),17,18 which are mutually associated.18 The psychosocial factors are associated with behavioral factors (eg, medication adherence).19,20 Behavioral factors (eg, sodium intake) are associated with physical factors (eg, HF symptoms).12 In the current study, we focused on the direct relationships of the multidimensional factors to HRQOL using a longitudinal study design. The findings of the current study can provide information that is required to develop effective interventions targeting improvement in long-term HRQOL.

FIGURE

FIGURE

Among the multidimensional factors, HF symptoms are among the strongest factors associated with HRQOL in cross-sectional studies.17,21 This fact is important because 90% to 100% of patients with HF have HF symptoms.22 In addition to relationships between HF symptoms and HRQOL, in 1 study,23 HF symptoms predicted HRQOL at 3 months. On the basis of these associational and longitudinal relationships between HF symptoms and HRQOL, we can hypothesize that changes in HF symptoms will be associated with changes in HRQOL. However, this hypothesis, especially the relationships between long-term changes in HF symptoms and HRQOL, has not been tested in patients with HF. If this hypothesis is supported, interventions to improve HRQOL should target improvements in symptoms.

Therefore, we examined, in a population of patients with HF, the associations of changes in HF symptoms with changes in the total HRQOL and the physical and emotional aspects of HRQOL over 12 months, controlling for the possible baseline predictors of sociodemographic and clinical characteristics (ie, age, comorbidities, NYHA functional class, and body mass index), psychosocial factors (ie, depressive symptoms, perceived control, and social support), and behavioral factors (medication adherence and sodium intake). In addition, because a 5-point or greater improvement in HRQOL is associated with reduction in hospitalization and mortality rates,7 we also examined whether changes in HF symptoms were associated with a 5-point or greater improvement in HRQOL assessed by the MLHFQ.

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Methods

Study Design, Settings, and Sample

Because the study design, settings, and sample were fully described elsewhere,12 information about these is presented here briefly. The study designs in both the parent study and the current study were longitudinal correlational. The purpose of the parent study was to examine the effects of baseline modifiable psychosocial and behavioral factors on symptoms and HRQOL at baseline and also at 12 months in patients with HF. Eligible patients were recruited from the clinics and units of several hospitals in 3 cities in the United States. Inclusion criteria were a diagnosis of HF (based on a medical record review), NYHA functional classes II to IV (based on in-depth face-to-face interview), and the ability to read and speak English. Exclusion criteria were cognitive problems based on the Mini-Mental State Examination test (score < 24),24 history of psychiatric diseases (except depression), and coexisting terminal illness such as cancer. In addition, patients with referrals for heart transplantation were excluded. The data collectors were trained for determination of NYHA functional class using the NYHA classification published by the American Heart Association.25 Then, the first author checked whether the NYHA functional class for the first patient of each data collector was correct or not.

The research team contacted eligible patients who were interested in this study and were referred by their healthcare providers or were self-referred. Eligibility was confirmed by the research team through medical record review and patient interview. The justification for the sample size was provided in the parent study.12 Considering a 5% significance level, an 80% power, 10 independent variables, and an effect size of 0.20 (medium, 0.15; and large, 0.35),17 the sample size of the current study was 91 (G*Power 3.1.5).26

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Ethical Consideration

This study was approved by 4 institutional review boards at the 3 sites. All participants (N = 94) gave written consent. The investigation was conducted according to the principles outlined in the Declaration of Helsinki.

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Measures

Health-related quality of life was defined as an individual’s perception of the effects of HF on various aspects of daily life1,12 and was assessed at baseline and 12 months by the MLHFQ, which consists of 21 items, each with 6-point response options.27 In addition to the total scale (overall HRQOL), the MLHFQ has 2 subscales to assess physical (8 items) and emotional (5 items) aspects of HRQOL. The total scale includes all items of the physical and emotional subscales and also other items regarding socioeconomic aspect, treatment, and some physical activities. Possible score ranges for the total scale and the physical and emotional subscales are 0 to 105, 0 to 40, and 0 to 25, respectively. Higher scores indicate poorer HRQOL. Reliability and construct validity in patients with HF have been supported,27 and Cronbach’s α in the current study was .94 at baseline and .96 at 12-month follow-up.

Heart failure symptoms were defined as common HF symptoms and were assessed at baseline and 12 months by the Symptom Status Questionnaire-Heart Failure, which consists of 7 combined items. Each combined item includes 4 subitems assessing presence, frequency, severity, and distress of 7 common HF symptoms. Except presence (yes or no), each subitem of frequency, severity, and distress has 4- or 5-point response options.17 Possible score range is from 0 to 84, with higher scores indicating more severe HF symptoms. Reliability and validity (eg, construct) have been supported,17 and Cronbach’s α for the 7 combined items in the current study was .83 at baseline and also at 12-month follow-up.

Depressive symptoms were measured at baseline by the Patient Health Questionnaire,28 which consists of 9 items, each with a 4-point response scale. Possible score range is from 0 to 27, with higher scores indicating more severe depressive symptoms.28 Reliability and validity (eg, construct) have been supported in patients with HF,29 and Cronbach’s α in the current study was .89.

Perceived control was defined as an individual’s perception of his/her ability to cope with and control his/her physical condition and life12,30 and was measured at baseline by the Control Attitudes Scale-Revised,30 which consists of 8 items, each with a 5-point response scale. Possible score range is from 8 to 40, with higher scores indicating higher levels of perceived control. Reliability and validity (eg, construct) have been supported in patients with HF,30 and Cronbach’s α in the current study was .79.

Social support was defined as an individual’s perception of the degree of support received from family, friends, and significant others.31 Social support was assessed at baseline by the Multidimensional Scale of Perceived Social Support,31 which consists of 12 items, each with a 7-point response scale. Possible score range is from 12 to 84, with higher scores indicating greater social support. Reliability and validity (eg, construct) have been supported in several populations, including patients with HF,13,31 and Cronbach’s α in the current study was .94.

Medication adherence was defined as the percentage of days that the participant took the correct number of doses during the recording period.12 Medication adherence was measured at baseline using the medication event monitoring system, which consists of a vial with a cap that includes a microelectronic monitoring device that records the time that the cap is opened and removed from the vial.12 A research team member, together with the patient, selected 1 cardiac-related medication (eg, angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker, or β-blocker) and put that medication into the container. The patient was given specific information about the medication container’s function and use and was asked to use it for 3 months.

We defined sodium intake as the amount of sodium excreted in the urine during a 24-hour period; this method is more objective than self-report.32,33 At baseline, patients were asked to collect urine in a container for 24 hours and to record, on a urine collection sheet, the time that collection started and finished, each urination time, and the volume of urine. The research team provided specific verbal and written instructions about the purpose for collecting and ways to collect urine over a 24-hour period.

Other sociodemographic and clinical characteristics were collected at baseline with a sociodemographic questionnaire and a clinical questionnaire to describe sample characteristics. Data on psychosocial and behavioral factors were collected only at baseline, and data on HF symptoms and HRQOL were collected at baseline and 12-month follow-up.

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Data Analysis

Multiple regression analysis was used to examine the relationship between changes in HF symptoms and changes in the total HRQOL and the physical and emotional subscales of HRQOL, controlling for covariates (predictors): age, comorbidities, body mass index, depressive symptoms, perceived control, social support, medication adherence, sodium intake, and NYHA functional class. To relate our current study to the results found in Moser and colleagues,7 a subsequent analysis was performed using logistic regression to examine whether changes in HF symptoms were associated with at least a 5-point improvement in the total HRQOL, after controlling for other baseline predictors (covariates). As noted in Moser et al,7 an improvement of 5 points or greater in HRQOL was associated with a decrease in hospitalization and mortality.

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Results

The mean (SD) age of the sample was 58.0 (14.2) years, and 58.5% were female. Approximately 58% of the sample was at NYHA functional class III or IV. Other sociodemographic and clinical characteristics are presented in Table 1. The mean (SD) score change in HF symptoms from baseline to 12 months was −3.8 (14.1) and in HRQOL was −9.2 (24.1), which indicate improvement in both variables. Both changes in HF symptoms and HRQOL in individual patients had wide ranges (HF symptoms, −46 [negative scores indicate improvement in HF symptoms] to 31 [positive scores indicate worsening of HF symptoms]; HRQOL, −72 [negative scores indicate improvement in HRQOL] to 57 [positive scores indicate worsening of HRQOL]) over 12 months. Fifty-one patients (54%) showed at least a 5-point improvement in HRQOL over 12 months.

TABLE 1

TABLE 1

In multiple regression analyses, among baseline sociodemographic and clinical characteristics (ie, age, comorbidities, and body mass index), baseline psychosocial factors (ie, depressive symptoms, perceived control, and social support), baseline behavioral factors (ie, medication adherence and dietary adherence), baseline physical factor (ie, NYHA functional class), and changes in HF symptoms, only changes in HF symptoms were associated with changes in the total HRQOL (Table 2; F = 6.922, R 2 = 0.455, P < .001) and the physical aspect of HRQOL (F = 6.319, R 2 = 0.432, P < .001) at 12 months. Greater improvement in HF symptoms was significantly associated with greater improvement in the total HRQOL and the physical aspect of HRQOL. In addition, greater improvement in HF symptoms and lower sodium intake were significantly associated with improvement in the emotional aspect of HRQOL (F = 6.699, R 2 = 0.447, P < .001).

TABLE 2

TABLE 2

In logistic regression analysis of the relationship between improvement in HF symptoms and an improvement of 5 points or greater in HRQOL, the model was significant (χ2 = 27.062, P = .003) and explained 33.4% of the variance in HRQOL. Hosmer and Lemeshow test showed the appropriate goodness of fit of the model (χ2 = 6.625, P = .578). Improvement in HF symptoms was associated with an improvement of 5 points or greater in HRQOL at 12 months (Table 3). A 10 point reduction in HF symptoms (improvement in HF symptoms) was associated with a 806% increase in the predicted odds of having an improvement of at least 5 points in HRQOL, after controlling all baseline predictors. The model correctly predicted 71.3% of those who would show an improvement of 5 points or greater in HRQOL at 12 months.

TABLE 3

TABLE 3

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Discussion

This study demonstrates that improvements in HF symptoms are needed for improvements in HRQOL. Improvement in HF symptoms was associated not only with improvements in overall HRQOL and the physical aspect of HRQOL but also an improvement in the emotional aspect of HRQOL. Improvement in short- and long-term HRQOL may be important for reducing hospitalization and mortality rates.7,8 The findings of this study show 1 important target of interventions—HF symptoms—for improvement in HRQOL. Other cross-sectional and longitudinal studies also found that HF symptoms were strongly associated with HRQOL,9,21,34 and baseline HF symptoms predicted 3-month HRQOL.23 However, the long-term association of changes in HF symptoms with changes in HRQOL, controlling for baseline predictors, to our knowledge, has not been studied. In the current study, change in HF symptoms that occurred between baseline and 12-month follow-up was an important independent factor associated with changes in HRQOL over a 12-month period. More importantly, the findings also show that change in HF symptoms was associated with at least a 5-point improvement in HRQOL, which has been associated with lower rates of hospitalization and mortality in a previous study.7 Ten point improvement in HF symptoms was associated with a 806% increase in the predicted odds of having an improvement of at least 5 points in HRQOL. Thus, the findings of the current study demonstrate the importance of continuous assessment and effective management of HF symptoms to improve HRQOL and may reduce hospitalization rates over time. Patients can fill out the symptom instrument in the current study during outpatient clinic visits for less than 5 minutes, and clinicians can check the information in less than 1 minute to assess and manage common HF symptoms.

One notable finding of the current study is that most of the factors that have been frequently associated with HRQOL in this population did not significantly predict changes in HRQOL. In the literature, older age,10,11 fewer comorbidities,11 lower NYHA functional classes,11,13 a lower body mass index,8 less severe depressive symptoms,9 greater perceived control,12 greater social support,13 and better self-care1 have been associated with better HRQOL. Inconsistency of the findings in the current study and the previous studies regarding the relationships of these factors to HRQOL may, in part, be explained by 2 reasons. First, none of the previous studies examined factors associated with changes in HRQOL over 12 months. Second, none of the previous studies included changes in HF symptoms in the models to examine the associations to changes in HRQOL over 12 months. The findings of the current study suggest the critical roles of changes in HF symptoms in long-term changes in HRQOL. The instrument that was used in the current study to assess HF symptoms is simple, and a patient can fill it out for less than 5 minutes. Thus, clinicians and researchers can use this instrument to assess and manage HF symptoms and check the changes over time. In the current study, higher sodium intake was significantly associated with the poorer emotional aspect of HRQOL and the likelihood of a 5-point improvement in HRQOL. These relationships have not been examined in HF. Thus, further studies are needed to understand and examine the effects of sodium intake on different aspects of HRQOL.

The current study has some limitations. All of the psychosocial and behavioral variables were not assessed at follow-up, so the relationships of their changes to changes in HF symptoms and HRQOL could not be examined. In addition, because of the study design, the causal relationships of changes in HF symptoms to changes in HRQOL could not be examined. Future studies can be conducted to examine these relationships. The mean age of the sample was relatively young, which can limit the generalizability of findings. In addition, further studies may be needed to consider other potential factors, such as antidepressants, in the relationships between changes in HF symptoms and changes in HRQOL over time.

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Conclusions

The findings of this study show that changes in HF symptoms are associated with changes in all aspects of HRQOL, controlling for typical multidimensional predictors, which suggest that improvement in HF symptoms may lead to improvement in HRQOL. Further studies are needed to develop and deliver interventions that effectively improve HF symptoms and to examine whether improvement in HF symptoms leads to improvement in HRQOL in patients with HF.

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What’s New and Important?

  • Long-term changes in HF symptoms were associated with long-term changes in HRQOL over 12 months, controlling for baseline predictors.
  • Long-term changes in HF symptoms (improvement) were significantly associated with the likelihood of at least a 5-point improvement in HRQOL, controlling for baseline predictors.
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Keywords:

heart failure; quality of life; symptoms

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