Hevey, David PhD; Brown, Angela MD; Cahill, Alison RN; Newton, Helen RN; Kierns, Mary RN; Horgan, John Henry MD
Cardiac rehabilitation (CR) is widely accepted as beneficial for cardiac patients. 1,2 Previous research has documented a significant reduction in mortality associated with multifactorial CR participation. 3–5 However, it has been well documented that CR services vary greatly, both between and within countries regarding program structure, delivery format 6 and personnel training. 7
Typically, CR programs are multifactorial, having a core component of exercise and education, and a combination of vocational rehabilitation, pharmacologic treatment, and psychological intervention, where necessary. 8 Education, counseling, and behavioral intervention have proved effective in influencing the outcomes of stress and psychological well-being. 1 The addition of these interventions to CR reduces morbidity and mortality and promotes secondary prevention. 5 Thus, current recommendations are for a comprehensive multifactorial approach to CR for optimal physiologic and psychological recovery. 8,9 However, much variation currently exists between centers in how CR services are delivered to patients.
In general, the current level of service provision in many countries means that only a few eligible cardiac patients are receiving CR. In addition, CR service provision tends to be poorest in those countries that actually have the greatest need for such services. 6 The optimal format of CR service delivery remains to be established and a need exists to evaluate how different delivery formats can best meet CR service demands. With a shorter program, it may be possible to increase the number of patients invited to participate in a CR program. To date, the effects of participation in a shorter program have not been compared with a standard comprehensive program nor a variety of outcomes from a CR program have not been systematically examined. Therefore, the present study was conducted to evaluate the effectiveness of a 4-week multifactorial CR program compared with a standard 10-week CR program on quality of life and exercise capacity.
Sixty consecutive referrals to the CR program were approached and asked to participate in a study examining CR. Patients were randomly assigned to either a standard 10-week (30 exercise sessions) or a 4-week (20 exercise sessions) multifactorial rehabilitation program. All exercise sessions lasted approximately 50 minutes and were conducted by trained CR coordinators 7 in an outpatient hospital setting. Exercise sessions were composed of warm-up, aerobic exercise, resistance training, and a cool-down period. All patients participated in telemetry-monitored exercise at all CR sessions. In accordance with standard recommendations, 8 exercise prescription was individualized and all patients exercised at between 60% to 80% of submaximal heart rate, based on a precardiac rehabilitation exercise stress test using the Bruce protocol. All patients were given guidelines for exercise on the days (weekends for the 4-week program and nonexercising days for the 10-week program) they did not attend the rehabilitation program. These guidelines were individualized and based on the participant’s performance and clinical status over the course of the exercise program. In addition, all patients were provided with an exercise prescription on completion of the program and prescriptions were compatible with the standard guidelines for continued exercise training.
In addition, all patients were given dietary advice, pharmacologic counseling, stress-management, and cardiac education. Vocational counseling and individual psychological counseling were provided, where appropriate. Patients had exercise testing before and immediately after CR, and again 6 months after CR. All patients exercised according to the standard Bruce protocol to 85% of maximal heart rate or ceased exercising if limited by symptoms. During exercise stress testing, patients were permitted to improve balance by resting an arm lightly on the side or front rail of the treadmill. METS were given by the readout from the exercise stress test machine (Marquette Case-8000) for each participant’s stress test result. * The post-CR exercise test was performed, on average, within 1 week after completion of the training program, for both the 4-week and 10-week programs. The final exercise test was performed 6 months after the completion of CR. Patients also completed the Medical Outcomes Study Short Form-36 (SF-36) 10 quality of life questionnaire and the Hospital Anxiety and Depression Scale (HADS) 11 scale at each time-point.
The number of exercise sessions each patient attended was assessed. Hospital re-admissions were assessed using the hospital’s computer database and patient medical chart. To assess changes in lifestyle after CR, patients completed a self-report scale on lifestyle.
Data were analyzed using two-way repeated measures of analysis of variance (ANOVA) with Scheffe post hoc tests. The between-group factor was type of CR program (10 or 4 weeks) and the within-groups factor was time (pre, post, and 6 months after CR). Post hoc testing was performed if statistically significant main effects or interaction were detected. Statistical significance was set at 0.05. If data were not normally distributed, they were transformed to meet the assumptions necessary for appropriate use of ANOVA. Categorical data analysis was performed using Fisher exact test.
Sixty consecutive patients were randomly assigned to either a 10-week (N = 30) or a 4-week (N = 30) CR program. One patient from each group did not accept the offer to participate in CR. The demographic details and attendance rate of the study sample are provided in Table 1.
Although no significant differences were found between the groups before CR, in relation to the demographic details assessed, the attendance rate in the 4-week group was significantly higher (P < .05) than that of the 10-week group. Analyses of the use of medication among participants showed that at the start of CR, 8 patients in the 4-week group and 9 patients in the 10-week group were taking beta-blockers. Over the course of the study, among the 4-week group, 13 participants had changes in medication with 7 of them started on beta-blockers and 6 having the dose or type of their beta-blocker changed. Among the 10-week group, 8 participants had changes in medication, with 5 starting beta-blockers and 3 having their dose or type of beta-blocker changed. None of the differences were significantly different using Fisher exact test.
The effects of the CR programs on exercise capacity over the three time points are presented in Table 2.
No significant interactions were detected and the post hoc analyses focused on the main effects of time. Both groups showed statistically significant improvements over the three time points in relation to the measures of exercise capacity. Compared with the baseline measure, significant increases were seen in exercise time and exercise capacity and a significant decrease in heart rate for equal workload. The effects of the CR programs on psychological mood and quality of life over the three time points are presented in Table 3.
A significant interaction was detected in levels of depression, with post hoc analyses showing a statistically significant difference between the two groups at the end of CR; the 10-week group had higher levels of depression than the 4-week group. No other significant interactions were detected and the post hoc analyses focused on the main effects of time. Both groups showed statistically significant improvements over the three time points in relation to energy and pain. A significant improvement was noted in both emotional and social well-being between pre-CR and the 6 month follow-up groups. Significant increases were seen in exercise duration and capacity, and a significant decrease in heart rate. These benefits were maintained 6 months after CR. Of note, significant interactions between time and type of cardiac rehabilitation program were detected. At 6-month follow-up, no significant difference was seen between the two groups in relation to re-admission rates, self-reported levels of exercise, return to work, and smoking.
The present study investigated the effects of a shortened CR program in comparison with a standard 10-week program. Results of this study show no significant differences between a shortened 4-week CR program and a standard 10-week program in relation to exercise capacity and quality of life. Only one significant interaction between group and time was detected and that was the higher levels of depression reported by the 10-week group at the end of the CR program.
Exercise capacity, as indexed by changes in exercise duration, capacity, and heart rate at equal workload, significantly increased over the study period in both groups; this finding supports the previously documented benefits of CR. 1,3 Comparison of post-CR testing requires the difference in timing to be considered when interpreting the results. Significantly, the 6-month comparison revealed similar results (ie, no difference) between the groups. Of note, the 4-week group started the study with an exercise capacity of 1 MET less than the 10-week group. It has been established that improvements in exercise capacity are dependent on the baseline level 1 and the present study supports these findings. Both groups showed improvement in a number of quality of life dimensions (eg, energy, pain, emotional well-being, social well-being, and general health). No significant differences were seen between the groups on any of the variables assessed 6 months after discharge from the program. All patients were provided with an individualized exercise prescription on completion of the program and the present data suggest that both sets of patients are adhering to lifestyle recommendations to the same extent. Of note, previous work has also demonstrated the beneficial effects of brief exercise sessions for CR patients. 12 Thus, whereas systematic reviews have suggested that longer programs are associated with better outcomes, 1 shorter programs may still represent a valuable CR service option.
The higher rate of attendance in the 4-week group (96% vs 84%) suggests that brief and intense CR programs are acceptable to patients. Investigators have assumed that the shorter program might be associated with lower attendance rates, given that it involved a significant time commitment (ie, daily attendance for 4 weeks). This finding was unexpected and may indicate potentially better compliance with shorter programs.
It has long been argued that CR programs should provide a menu of services and it may be that certain cardiac populations benefit from participation in shorter programs. Such populations may include patients with percutaneous transluminal coronary angioplasty, whose perception of themselves as being less ill may be better accommodated by shorter programs and early return to work, may also be facilitated. Thus, it may be desirable to offer patients a variety of CR formats. It is not possible, however, to identify those individuals who would benefit most from participating in a shorter program based on current literature. The present findings suggest that further research, addressing the relative impact of different CR formats on different cardiac populations, is warranted. In the current climate of scarce healthcare resources, the cost-effectiveness of different CR formats requires investigation.
The present study was an initial investigation of the impact of different CR programs and, as such, the possibility of not detecting a significant difference may result from type II error (ie, low power). A sample size of 30 was selected as being feasible for an initial investigation and, clearly, similar studies should include larger numbers of participants. The present study varied both the duration and the number of sessions per week and future studies could investigate the effects of manipulating these factors individually. The present study compared two programs that differed in exercise session by 50% (ie, 30 sessions in the 10-week program compared with 20 sessions in the 4-week program) and future studies should investigate programs with a greater difference in sessions.
The primary aim of the current study was investigate the benefit on exercise training of a shorter program in terms of efficacy, in response to growing demands being placed on the service. Whereas a number of self-reported lifestyle behaviors were assessed at time 3 (6 months post-CR), a limitation of the study includes the lack of objective assessment of smoking, body mass index, lipids, and lipoproteins. Nevertheless, it is possible that a 4-week exercise program could be supplemented with a lengthened education and health counseling service.
Lack of a control group means that the effects of familiarity with the treadmill walking on subsequent performance cannot be estimated. Such comparisons would provide valuable insight into the determinants of improvement in exercise time. Furthermore, respiratory gas exchange was not measured, and we acknowledge this limitation.
Although the absence of a nonexercising control group limits the strength of conclusions drawn, the present study was conducted to compare the effectiveness of two treatment formats and the exercise program used was based on current recommendations. 8 Of note: the general level of fitness of both groups was high, which may suggest that the sample was composed mainly of patients at low risk. Thus, caution should be used in generalizing these results to a high-risk population. An additional limitation arises from the fact that participants entering the CR program are not stratified. Rather, all patients are carefully evaluated clinically before rehabilitation and heart rate and rhythm monitoring are conducted during exercise sessions. Furthermore, the high attendance rate suggests a highly motivated patient group that may not be representative of CR populations in general.
No significant differences were detected between groups having a 10-week or a 4-week course of CR. A 4-week multidisciplinary CR program produces similar improvements in exercise capacity and quality of life as a 10-week program. Preliminary data suggest that shortened courses may be beneficial to cardiac patients and such courses may facilitate more widespread use of CR.
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