Randomized trials of secondary prevention programs in coronary artery disease : a systematic review : final report

DESIGN: Randomized clinical trials (RCTs) of secondary prevention programs in patients with CAD were identified by searching Medline 1966-2004; the Cochrane Central Register of Controlled Trials, Issue 4, 2004; Embase 1980-2004; CINAHL 1982-2004; SIGLE 1980-2004; the Cochrane Effective Practice and...

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Main Authors: Clark, Alexander M., McAlister, Finlay (Author), Hartling, Lisa (Author), Vandermeer, Ben (Author)
Corporate Authors: United States Agency for Healthcare Research and Quality, Tufts Evidence-based Practice Center
Format: eBook
Published: Rockville, Maryland Agency for Healthcare Research and Quality December 5, 2005, 2005
Series:Technology assessment
Online Access:
Collection: National Center for Biotechnology Information - Collection details see MPG.ReNa
Summary:DESIGN: Randomized clinical trials (RCTs) of secondary prevention programs in patients with CAD were identified by searching Medline 1966-2004; the Cochrane Central Register of Controlled Trials, Issue 4, 2004; Embase 1980-2004; CINAHL 1982-2004; SIGLE 1980-2004; the Cochrane Effective Practice and Organization of Care Study Registry; bibliographies of published studies, and via contact with experts in the field and references provided by the Centers for Medicare and Medicaid Services and authors of the primary studies. Studies were excluded if the program being evaluated consisted of supervised exercise training only; studies were selected and data extracted independently by 2 investigators, and summary risk ratios were calculated using the random effects model.
BACKGROUND: While it is well established that cardiac rehabilitation programs employing supervised exercise training improve outcomes in survivors of myocardial infarction, the effects of secondary prevention programs which are not primarily exercise-based are unclear. OBJECTIVES: To determine whether secondary prevention programs for patients with established coronary artery disease (CAD) improve health outcomes. To characterize secondary prevention programs which have been evaluated in the literature and to identify any program-related factors which influence effectiveness for patients with established coronary artery disease (CAD). Of note, secondary prevention programs which consisted of exercise training alone were not included in this review.
None of the program characteristics demonstrated a significant effect on all-cause mortality or on recurrent myocardial infarctions- indeed, the mortality benefit seen with short-term interventions (less than 10 hours of patient-provider contact time) was similar to the overall pooled result: RR 0.80, 95% CI 0.68 to 0.95, in 4307 patients from 9 trials. For hospitalizations, programs with increased degrees of individualization exerted greater impacts (p<0.001 in meta-regression, RR 0.74, 95% CI 0.65 to 0.85). Secondary prevention programs had positive impacts on processes of care: patients randomized to these programs were more likely to be prescribed efficacious medications and 22 out of 27 trials evaluating cholesterol profiles demonstrated improvements with these programs compared to usual care (in 14 trials the improvements were statistically significant, with effect sizes in the small to moderate range).
The summary RR was 0.87 (95% CI 0.79-0.97) for all-cause mortality in the 29 trials (13 857 patients) reporting this outcome, but this result differed over time with a RR of 0.97 (95% CI 0.82-1.14) for 12 month all-cause mortality in the 19 trials (9393 patients, p for heterogeneity=0.95, I-squared=0%) reporting this timeframe and a RR of 0.53 (95% CI 0.31-0.92) for all-cause mortality at 24 months in the 4 trials (1367 patients, p for heterogeneity=0.44, I-squared=0%) reporting this timeframe. The summary RR was 0.83 (95% CI 0.72-0.96) for recurrent myocardial infarction and 0.84 (95% CI 0.74-0.97) for hospitalization rates over a median follow-up of 12 months. There were no appreciable differences between the 3 types of secondary prevention programs we examined in their effects on mortality, hospitalizations, or recurrent myocardial infarctions.
Eighteen of the 30 trials evaluating quality of life or functional status reported statistically significantly better outcomes in those patients exposed to the intervention programs, although the effect sizes were generally small. None of these trials were double-blind and Jadad quality scores were clustered around 2. Physicians adopted a coordinating role in only 4 (9%) programs. Only one quarter of the programs were based on specific guidelines. Around one third offered standardized programs, though the greatest proportion of these programs (43%) had some individualization to the degree expected with usual care. CONCLUSIONS: Secondary prevention programs improve processes of care, enhance quality of life/functional status, reduce hospitalizations, reduce recurrent myocardial infarctions, and reduce mortality in patients with established CAD. There is inadequate data to conclusively comment on the incremental benefits of specific components contained within these programs.
Though most programs are likely to involve specialist health professionals, physicians adopt an active coordinating role in only a small minority of programs. Programs with more individualization are more effective at reducing hospitalizations and even short-term programs (less than 10 hours of provider-patient contact) demonstrate mortality benefits
Each intervention was classified a priori into one of 3 groups: (1) Comprehensive Cardiac Rehabilitation (those interventions which consist of exercise training plus group education and counseling sessions about coronary risk factor management), (2) Group Cardiac Rehabilitation without exercise component (programs which include group education and counseling sessions about coronary risk factor management, but without a structured exercise component), or (3) Individual Counseling (programs, usually delivered by specially trained nurses, which involve individual education and counseling sessions with individual follow-up, either in person or by telephone, to encourage coronary risk factor optimization). Primary study authors were contacted for additional details about their programs. The association of program characteristics with the main outcomes were examined using a forward step-wise meta-regression. RESULTS: A total of 46 RCTs (18 821 patients with CAD) were identified.
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