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ORIGINAL ARTICLES |
From the School of Psychology (D.H.), Trinity College Dublin, Ireland; Department of Psychology (H.M.M.), Royal College of Surgeons in Ireland, Ireland; and the Department of Cardiology (J.H.), Beaumont Hospital, Dublin, Ireland.
Address correspondence and reprint requests to David Hevey, School of Psychology, Trinity College Dublin, Dublin 2, Ireland. E-mail: heveydt{at}tcd.ie
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ABSTRACT |
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Methods: Cardiac patients completed a questionnaire battery at the start and finish of a CR program (n = 131) or at equivalent times after hospital discharge in comparison hospitals where CR was not available (n = 185). The questionnaire battery comprised the Hospital Anxiety and Depression Scale, the Health Complaints Scale, and the Quality of Life Index Cardiac Version III (QLI CV-III).
Results: Significant correlations between initial levels and subsequent changes in distress and HRQOL measures were found for both the CR and comparison groups. The CR program was associated with significant changes in both somatic and cognitive complaints for only those in distress. Changes in functional and psychological morbidity were greater in the CR group than in the comparison group.
Conclusions: Changes in HRQOL were significantly related to the initial levels of distress found in cardiac patients, regardless of CR attendance. The CR program had beneficial effects on levels of functional ability and on psychological morbidity reduction. Implications of the research for CR outcomes assessment are considered.
Key Words: cardiac rehabilitation • distress • HRQOL • depression • anxiety
Abbreviations: CR = cardiac rehabilitation; HRQOL = health-related quality of life; HADS = Hospital Anxiety and Depression Scale; HCS = health complaints; QLI CV-III = Quality of Life Index Cardiac Version III.
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INTRODUCTION |
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The detrimental effects of distress on recovery from cardiac events have been widely documented (2). CR psychosocial interventions, typically a combination of stress management and psychoeducation, have a modest impact on reducing levels of depression and anxiety (3,4). Such interventions are provided routinely to all CR participants despite the fact that the majority of cardiac participants do not experience pathological levels of distress, and a substantial change in levels of distress would not be expected for these patients over the course of CR (5). The provision of expensive psychological services to all patients raises questions regarding the cost effectiveness of this approach. For example, an intensive nurse-led psychological intervention produced a significant effect on mortality and mortality among patients with post myocardial infarction classified as highly stressed before hospital discharge; however, there was no effect of the intervention among those classified with low level of stress in hospital (6).
Distressed cardiac patients have reported significant benefits from completing a multidisciplinary CR program. Milani, Lavie, and Cassidy (7) reported that at the start of CR the more depressed cardiac patients had poorer risk profile and had lower HRQOL scores. At the end of CR, the depressed group showed similar improvements as the nondepressed group in their cardiovascular clinical risk profile. In addition, the depressed group reported a greater degree of improvement in psychological status compared with the nondepressed group. Similarly, Lavie and Milani (8) reported that, in a sample of consecutive CR participants, the anxious group showed comparable gain as the nonanxious group across clinical risk factors and showed greater gain in some HRQOL domains.
There is evidence that initial levels of psychological distress are associated with significant HRQOL change over the course of CR; however, the extent to which observed changes in HRQOL among distressed CR patients represent regression to the mean remains unclear. The absence of comparison groups from studies produces uncertainty regarding the extent of natural change over time in HRQOL. In addition, the presence of floor and ceiling effects in HRQOL measures results in program evaluations potentially underestimating or missing the effects of treatment or natural history on HRQOL. The present study examines the relationship between initial levels of distress and changes in HRQOL in a sample of CR and comparison cardiac patients.
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METHODS |
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Participants
Ethical approval for the study was obtained from the School of Psychology, Trinity College Dublin. All patients were provided with a standard research information sheet and consent form. Consecutive patients attending CR in 2003 to 2006 were invited to participate and comparison patients were identified as those assumed to be eligible for CR. Cardiac patients typically not referred for CR in the study centers included those diagnosed with unstable angina and heart failure.
Trained clinical psychologists provided eight 1-hour group-based cognitive behavioral stress-management intervention as part of the multifactorial CR program. Each group consisted of six to eight participants and the intervention and comprised sessions on self-monitoring, cognitive restructuring, identifying sources of stress, using problem-focused as opposed to emotion-focused coping strategies, adherence to secondary prevention recommendations, and relaxation training. In addition, patients completed three structured exercise sessions (50 minutes) per week for 10 weeks and received input on dietary advice, pharmacological counseling, and cardiac education. The comparison patients received usual care and were not offered any psychological services as such services were not available in these hospitals.
Procedure
CR participants completed the questionnaire battery at the start (time 1) and the end (time 2) of CR. In comparison hospitals, questionnaires were mailed to participants at a time after hospital discharge equivalent to the start of the CR program. Time 2 questionnaires were mailed 10 weeks later and postal reminders were sent where necessary.
Measures
Physical Function
The Duke Activity Status Index is a 12-item self-report questionnaire that measures functional ability (10). Responses to items based on common physical activities that are carried out in a normal routine (e.g., walking, housework, sports) are weighted based on the metabolic costs of each activity. Items are summed to produce an overall score.
Psychological Status
The questionnaire battery included a measure of psychological distress and two cardiac-specific HRQOL measures—one generic and one domain-specific. The Hospital Anxiety and Depression Scale (HADS) is a 14-item instrument developed to detect states of anxiety (7 items) and depression (7 items) in medical outpatients (11). A recent review supported the psychometric properties and the clinical utility of the HADS in cardiac populations (12). In the present study, reliability for the depression (
= 0.72) and anxiety ( = 0.80) scales was satisfactory.
The Health Complaints Scale (HCS) assesses 12 commonly cited somatic and 12 cognitive complaints in cardiac patients, and high levels of internal consistency ( > 0.80) and test-retest reliability (r > .69) have been reported in a CR population (13). Satisfactory reliability for the somatic ( = 0.82) and cognitive ( = 0.91) scales was reported in the present study.
The Quality of Life Index Cardiac Version III (QLI CV-III) consists of 72 items, composed of two parts (14). Part 1 comprises 36 items measuring satisfaction with various domains of life and Part 2 comprises 36 items assessing the importance of each domain to the respondent. Domains include health and functioning (16 items), socioeconomic (9 items), psychological/spiritual (7 items), and family (4 items). In the present study, Cronbach's for health and functioning ( = 0.88), socioeconomic ( = 0.77), psychological ( = 0.84), and total quality of life ( = 0.90) scales was satisfactory; however, the family scale had a lower reliability ( = 0.58).
Analysis
Data were screened for outliers and normality of distribution using graphical (i.e., histogram, box-plot) and statistical (i.e., Shapiro-Wilk test) means. Group comparisons between two groups were performed using independent samples t test. Comparisons of categorical data were made using 
2 analyses and changes in categorical data over time were examined using McNemar's test. Pearson correlations between the initial levels and changes in the variables are reported for the CR and comparison groups separately. All change scores were coded such that a positive value represented a positive change (i.e., increase in function, decrease in distress, or increase in HRQOL). To examine change over time, a 2 (CR versus comparison) x 2 (time 1 versus time 2) mixed analysis of variance with post hoc tests was performed. Statistical significance was set at .05.
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RESULTS |
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At time 1, there was no difference between the groups in functional status; however, analysis of time 2 functional scores, controlling for time 1 levels, demonstrated a statistically significant difference (F(1,299) = 4.8; p = .03) with the CR group (mean = 39.4) reporting significantly higher functional levels than the comparison group (mean = 38.7).
At time 1, 15% (n = 48 patients) of the sample scored in the clinical range on the HADS. The 48 distressed patients comprised 28 meeting the criteria for clinical anxiety only, 2 for clinical depression only, and 18 for both clinically anxiety and depression. There were no significant differences between the CR group and comparison group in relationship to the percentage of participants classified as clinically depressed or clinically anxious at each time point (Figure 1).
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The CR group reported statistically significant changes over time in the numbers of cardiac patients scoring in the clinical depression range (50% decrease; p = .03) and clinical anxiety range (30% decrease; p = .03); changes in the comparison group were not significant.
Relationship of Initial Levels to Changes in Distress and HRQOL
The correlations between the baseline distress and HRQOL values and the subsequent change in the scales are presented for the CR group and comparison group separately (Table 2).
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The correlation between the initial level and the change was statistically significant for all variables in both groups except for the psychological domain of the QLI CV-III in the comparison group. A statistically significant difference in correlation coefficients was found between the CR and comparison groups in relationship to somatic complaints, cognitive complaints, health, social, psychological, and total quality of life (QoL). Further analyses of these differences demonstrated two patterns.
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DISCUSSION |
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The significant correlation between initial levels and subsequent changes in distress and HRQOL measures for both the CR and comparison groups raises the question of the effect of CR over and above effects of time. Significant changes over time in anxiety and depression were related to the initial level of distress, rather than CR participation. For example, those cardiac patients in the clinical range reported substantial decreases in scores on both the HADS anxiety and depression scales over time. Observed changes in distress and HRQOL in the current sample may indicate a regression to the mean effect (15) or spontaneous remission in symptoms. Of note, in a recent comparison of an intensive lifestyle modification intervention, CR and usual care, regression to mean was suggested as an explanation of some of the reported improvements in psychological mood and QoL domains (16).
These findings raise issues for the routine provision of specific psychological interventions to all cardiac patients. Delivery of psychological input by trained clinical psychologists is expensive; in an evaluation of CR services in the UK, it has been estimated that the cost per hour of a clinical psychologist in CR is the third highest after general practitioner and medical consultant costs (17). As clinical psychology services are expensive, this raises the possibility that such limited services may be more efficiently delivered to select patients only. Screening patients to identify those in distress would facilitate targeted delivery of appropriate distress-reducing psychological interventions.
The findings have implications for routine HRQOL outcomes assessment in CR. Because most cardiac patients do not experience psychopathology, outcome measures with items that do not address issues relevant to the majority of coronary patients may suffer from floor and ceiling effects, which complicate program evaluation. In response to this concern, the HCS was developed specifically to assess psychosocial states that actually change over the course of CR (13). In the current study, only those high in distress who received CR reported a statistically significant decrease in both HCS somatic and cognitive complaints. Those high in distress who received usual care reported high levels of both somatic and cognitive complaints at each assessment. Previous research using the HCS reported that CR participants showed statistically significant improvements on both subscales, but comparison patients reported no significant changes (13).
CR was associated with a number of significant functional and psychological morbidity benefits that were greater than that achieved in the comparison group. The CR group reported a statistically significant increase in functional status whereas the comparison group showed no significant change. The beneficial effect of CR on physical status is well established (18). The present data indicate that the CR intervention was successful in helping participants improve the physical capacity required to perform routine activities of daily living. The 50% decrease in the number of participants scoring in the clinical depression range and 30% decrease in the number of participants scoring in the clinical anxiety range represent a clinically significant reduction.
Limitations
For ethical reasons, a randomized controlled trial was not feasible; however, the participants' profile suggests that the sample was representative of the CR population and that the two groups were well matched in terms of demographic and medical profiles. The HADS was used to identify clinically anxious and depressed cardiac patients. Although a number of reviews have supported the use of the HADS as a screening tool, the gold standard for detecting psychological distress remains a standardized clinical interview such as SCID (Structured Clinical Interview for DSM Disorders).
The comparison patients were not offered any psychological services through the hospital. At time 2, patients were asked about mental health service use after completing the time 1 questionnaire. No patients reported consulting with a mental health professional; however, this was based on self-report and, in addition, patients were not asked if they had attended any support groups. These limitations raise the possibility that patients may have received some interventions that confound the interpretation of the analyses.
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CONCLUSION |
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NOTES |
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DOI:10.1097/PSY.0b013e318156bcd2
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