Note: CABG = coronary artery bypass graft surgery; CHD = coronary heart disease; ECG = electrocardiographic; HDL = high-density lipoprotein; LDL = low-density lipoprotein; MI = myocardial infarction; PTCA = percutaneous transluminal coronary angioplasty.

In summary, the 18 randomized controlled trials reported changes in lipid and lipoprotein levels (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides) as a result of rehabilitation services, including exercise training. Favorable outcomes included significant reductions in total cholesterol, LDL cholesterol, and triglyceride levels and significant increases in HDL cholesterol levels. The 18 trials reported 46 comparisons: 26 were significant favorable changes, and 20 showed no significant differences between intervention and control groups. Of the 26 favorable lipid outcomes, 22 resulted from multifactorial rehabilitation, that is, dietary and behavioral strategies in addition to exercise training and, in some studies, the use of lipid-altering medications. Among the 20 lipid comparisons that showed no differences between rehabilitation and control patients, 13 came from multifactorial interventions (Figure 3). Thus, favorable changes in lipid levels are more likely to result from multifactorial cardiac rehabilitation. Most of these randomized controlled trials involved patients following myocardial infarction (nine studies), with varied presentations of coronary disease (eight studies), or following CABG (three studies).

Six nonrandomized controlled studies reported changes in lipid levels following exercise rehabilitation. One study did not report sufficient lipid data for evaluation,169 and three of the remaining five studies reported statistically significant beneficial lipid changes favoring rehabilitation versus nonrandomized control patients. 20,158,207 One additional trial reported significant increases in mean HDL cholesterol levels following 6 months of exercise rehabilitation. 172 Eight of the 13 observational reports described favorable changes in lipid levels after exercise training, with and without other rehabilitation interventions; 30,173,186,189,196,198,200,234 five reports indicated no significant improvement in lipid levels. 164,182,202,223,235

Conclusions

Improvement in lipid profiles resulting from multifactorial cardiac rehabilitation is well established by review of the scientific literature. Most randomized controlled trials reported beneficial effects on total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels favoring rehabilitation versus control patients. Well-designed nonrandomized controlled trials reported similar beneficial outcomes. The rehabilitation studies that reported the most favorable impact on lipid levels were multifactorial, that is, providing exercise training, dietary education and counseling, and, in some studies, pharmacologic treatment, psychological support, and behavioral training. The specific effects of exercise training alone on lipid changes could not be isolated with a multifactorial rehabilitation study design. These favorable effects on lipid profiles involved patients who were both younger and older than 65 years of age. Although a small proportion (10-22 percent) of women participated in some studies, no study reported lipid outcomes by gender. Furthermore, no study reported lipid outcomes by age. In addition, the confounding variable of concomitant weight loss was not analyzed and could have an independent influence on lipid changes.

Figure 3. Changes in lipid levels in 18 randomized controlled trials of cardiac rehabilitation by intervention strategy-exercise only versus multifactorial intervention

Note: Effects of types of cardiac rehabilitation interventions on lipid levels in randomized controlled trials (significant reductions in total cholesterol, LDL cholesterol, and triglyceride levels, and significant increases in HDL cholesterol levels). Multifactorial rehabilitation interventions appear more likely to effect a beneficial change in lipid levels than does exercise training alone. All trials compared rehabilitation versus control patients. Some studies reported more than one lipid result.

The panel concurs with the recommendation of The Second Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II) (NCEP II) regarding the role of physical activity for lipid control, namely "the appropriate use of physical activity is considered an essential element in the nonpharmacologic therapy of elevated serum cholesterol."236

The panel also noted the results of a major randomized placebocontrolled trial of cholesterol lowering in 4,444 patients with CHD, 80 percent with prior myocardial infarction. Patients who were treated with a cholesterol-altering medication showed a significant reduction in total mortality (p = .0003), coronary death, and major coronary events (p < .00001) compared with placebo-treated patients. No difference in noncardiovascular mortality was documented. Favorable results occurred in patients who were both younger and older than 60 years of age and in both men and women. The panel agrees with the trial conclusions that patients with coronary disease and diet-resistant cholesterol levels above 210 mg/dL should be considered for treatment with lipid-altering medication.237

Body Weight

RECOMMENDATION

Cardiac rehabilitation exercise training as a sole intervention has an inconsistent effect on controlling overweight and is not recommended as a sole intervention for this risk factor. Optimal management of overweight requires multifactorial rehabilitation including nutritional education and counseling and behavioral modification in addition to exercise training. Scientific Evidence (Strength of Evidence = C)

The scientific evidence pertaining to the effect of exercise training on body weight included 34 scientific reports. Eleven of these studies were randomized controlled trials, 7 were nonrandomized controlled studies, and 16 were observational reports.

Two of the 10 randomized controlled trials involved exercise training as the sole intervention. One documented favorable reduction in body weight in intervention versus control patients,17 and the other showed no significant difference.10 One study compared exercise training with exercise training plus education/counseling with a control group and documented no significant difference between the three groups in weight loss at the 3- and 6-month followups.108 Seven randomized controlled trials were multifactorial and included nutritional education and counseling, as well as behavioral modification; five reported changes in body weight, with two documenting a favorable outcome in intervention patients compared with control patients14,41 and three reporting no significant difference.9,16,228 Body mass index was addressed in three randomized controlled trials, with all documenting significant improvement favoring rehabilitation versus control patients;22,37,39 one also reported significant improvement by skin-fold measurements.39

No randomized controlled trial reported results separately by age of patients or by gender. Stratification by degree to which patients were overweight or by adiposity at baseline related to changes in measures of body weight or percentage of body fat was not carried out.