|Psychological treatment of cardiac patients: a meta-analysis
|Linden W, Phillips M J, Leclerc J
This review found that psychological treatment of cardiac patients reduces the risk of mortality in men. The effect was present in short- but not long-term follow-up, and not present in women. Limitations in the review methodology, including the potential for bias in the study selection and the absence of a validity assessment, mean that the reliability of the authors' conclusions is uncertain.
To determine the effectiveness of psychological treatments (PTs) on reducing mortality in cardiac patients, and to assess whether the effect differs according to patient gender, timing of treatment, length of follow-up or change in patient affect.
PsycINFO, Web of Science, MEDLINE, PubMed and EMBASE were searched from 2002 to 2006, following a protocol outlined by the Cochrane Database of Systematic Reviews; the search terms used were listed. References from previous meta-analyses were identified. Key researchers in the field were contacted to ask about other studies or unpublished data. Studies published in English, German, Portuguese, Chinese, Russian, Dutch, Swedish, Spanish and Danish were eligible for inclusion.
Randomised controlled trials of PTs compared with usual care (UC) in cardiac patients were eligible for inclusion if there were 20 or more patients in the intervention arm. The primary review outcomes were psychosocial, morbidity or mortality. Studies that reported other outcomes (e.g. changes in lipid levels) were excluded, as were studies where the PT was not separated from other components of cardiac rehabilitation.
In the included studies, patients had one or more of the following: percutaneous coronary interventions, coronary angina, coronary heart disease, myocardial infarction, coronary artery bypass graft. Where reported, the mean age of the participants ranged from 38 to 73 years and the proportion of women from 0 to 100%. Treatment duration ranged from 2 days to 12 months, and average treatment exposure was 16.3 hours (range: 0.67 to 52.5). The duration of follow-up ranged from 3 to 60 months.
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.
Assessment of study quality
The authors did not state that they assessed validity.
Two authors independently assessed the intervention and control treatments in each trial into one of four categories: basic UC, multi-component UC, multi-component PT and biological/self-regulation treatments. Each of these was clearly defined in the review. Any disagreements were resolved by discussion. Morbidity was defined as one or more of the following: rehospitalisation for cardiac emergency or new cardiac procedures, new myocardial infarction, newly diagnosed arrhythmias or persistent angina.
Methods of synthesis
The studies were combined using random-effects meta-analysis, with studies weighted by their sample size. Only comparisons involving over 200 patients were synthesised using meta-analysis. Dichotomous outcomes were synthesised using pooled odds ratios (ORs). Reductions in mortality of at least 20% were considered clinically meaningful even if they did not reach statistical significance (p<0.05). Continuous outcomes were first computed as Cohen’s effect sizes (d) then converted to r scores and pooled as weighted mean differences, although the authors did not term the outcome as this. Statistical heterogeneity was investigated using the I2 statistic. Subgroup analyses according to patient gender, timing of treatment initiation and change in patient affect were defined a priori.
Results of the review
The authors identified 43 studies, of which 23 (including 9,856 patients) reported mortality outcomes.
PT was associated with a reduction in risk of all-cause mortality at 2 years compared with UC (OR 0.72, 95% CI: 0.56, 0.94), with little evidence of heterogeneity (p=0.06). Among the 6 studies which reported outcomes at over 2 years, this effect was reduced and no longer significant (OR 0.89, 95% CI: 0.69, 1.14). In 10 studies which reported gender-specific results, PT had a greater beneficial effect in men (OR 0.73, 95% CI: 0.51, 1.05) and no effect in women (OR 1.01, 95% CI: 0.46, 2.23). The beneficial effect of PT was stronger for studies that initiated treatment more than 2 months after the event (OR 0.28, 95% CI: 0.12, 0.70) compared with those that began PT earlier (OR 0.87, 95% CI: 0.75, 1.20). There was a beneficial effect of PT in studies in which the PT achieved distress reduction (OR 0.46, 95% CI: 0.28, 0.75), whereas PT had no effect on mortality when stress reduction had not been achieved (OR 0.67, 95% CI: 0.27, 1.65).
The association between PT and morbidity followed the same patterns as for mortality.
PT was was associated with a statistically significant reduction in heart rate (-0.21) compared with UC, and it also improved both social support (r = -0.16) and quality of life (r = -0.34). In women, there were beneficial effects of PT on levels of distress and improved social support, whereas in men the effect was seen in greater reduction of depression and improved social support in treated compared with UC groups.
Treatment of cardiac patients with psychological interventions reduces mortality and morbidity in men but not women. PT was more effective if initiated 2 months after the cardiac event rather than immediately.
This review answered a clearly stated research question. The search strategy was comprehensive and unlikely to have missed relevant evidence. Attempts were made to reduce the potential for language bias by including studies from a range of languages, and to reduce publication bias by asking key researchers for unpublished data. However, publication bias was not formally assessed. The methodology used to select the studies and extract the data was not adequately described to exclude the possibility of error or bias during these parts of the review process. No quality assessment was reported, although the authors noted that the quality of non-English language studies tended to be poorer than those reported in English. The methods used to synthesise the data, including the use of subgroup analyses to investigate heterogeneity, were appropriate.
The reliability of the authors’ conclusions is uncertain given the lack of a validity assessment and the poor reporting of the review process.
Implications of the review for practice and research
Practice: Patients should be assessed regularly during cardiac rehabilitation for distress and depression, and PT offered until distress is reduced.
Research: The development of PT appropriate for women is required. Further research is also needed on the type of PT that is most effective; whether distress screening prior to PT is required; appropriate duration of treatment; and the role of PT in situations of high- versus low-quality UC.
Canadian Institutes for Health Research; Social Sciences and Humanities Research Council of Canada.
Linden W, Phillips M J, Leclerc J. Psychological treatment of cardiac patients: a meta-analysis. European Heart Journal 2007; 28(24): 2972-2984
Subject indexing assigned by NLM
Aged; Cardiovascular Diseases /mortality /rehabilitation; Epidemiologic Methods; Female; Humans; Male; Mental Disorders /prevention & control; Middle Aged; Psychotherapy /methods; Randomized Controlled Trials as Topic
Database entry date
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.