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How Cardiac Rehabilitation Relates to Quality of Life
The purpose of this study is to determine the relationship between adherence to cardiac rehabilitation (CR) and improvements in health-related quality of life (HRQL) with a 12-week, Phase-II CR program. Previously collected data from 153 CR patients (114 males, 39 females; 69.1 years of age ± 11.5) were utilized to complete this retrospective study. Patients completed the Medical Outcomes Survey Short Form-36 to assess HRQL at the beginning of CR (N = 153), at 3 months (N = 152), and at 1 year (N = 94). Pearson correlation coefficients were generated to assess the relationship between CR attendance and HRQL. Paired sample t-tests helped determine the effect of CR on HRQL at 3 months and 1 year. No relationship was found between CR adherence and improvements in HRQL. Significant improvements in HRQL were found among all patients from baseline to 3 months and 1 year. Study findings demonstrate the effectiveness of CR in improving patient short- and long-term HRQL regardless of patient adherence rate.
Cardiac rehabilitation (CR) plays an essential role in the management, as well as prevention, of coronary heart disease (Leon et al., 2005). The benefits of CR have been thoroughly documented in the literature (Leon et al.; Wenger et al., 1995). However, despite CR’s benefits, many patients fail to participate or fully adhere to rehabilitation. Indeed, only 15% of eligible cardiac patients attend a formal rehabilitation program (American Heart Association [AHA], 1994). Of those who do attend, many drop out within the first few months (AHA; Dorn, Naughton, Imamura, & Trevisan, 2001). Although many have sought to understand why patients do not adhere to CR, little is known about the benefits CR participants receive at various levels of attendance or adherence (Dorn, Naughton, Imamura, & Trevisan).
Understanding the benefits of CR for patients regardless of adherence level may help practitioners better individualize CR to meet patient needs. For instance, because of limitations imposed by health insurance providers, Phase-II CR program length has traditionally been limited to 36 sessions delivered over a 12-week period (Brubaker et al., 1996). However, this traditional program may not be ideal for all cardiac patients because the number of sessions and program length to provide maximal benefit may depend on the individual patient. However, it is essential to clarify the relationship between adherence to CR and benefits cardiac patients achieve through participation.
The purpose of this study was to determine the relationship between adherence to a traditional, 12-week, Phase-II CR program and the short- (3-month) and long-term (1-year) benefits resulting from program attendance. Benefit was determined by assessing the patients’ health-related quality of life (HRQL), a common outcome measure utilized within CR programs to assess health status (Oldridge, 1997).
The study was conducted at Banner Baywood Heart Hospital in Mesa, AZ, a nonprofit hospital devoted primarily to cardiac care. The cardiac rehabilitation program at this institution serves patients with cardiac disease, including individuals recovering from open-heart surgery and myocardial infarction, as well as patients with stable angina.
This retrospective study included 153 patients (114 males, 39 females; 69.1 ± 11.5 years of age) who participated in CR from March 2001 to December 2002. Prior to the collection and analysis of patient data, the study was approved by the organization’s institutional review board. To be included in the study, patients had to have completed the HRQL assessment at baseline and at 3 months or 1 year following. A total of 455 patients were assessed during the study time period and 34% of these patients (N = 153) met the inclusion criteria. All patients during the study were given the opportunity of completing the HRQL assessment. The average adherence rate (i.e., the percentage of sessions out of the total 36 sessions prescribed that patients attended) for the original group of 153 was 54%, or 19 out of a possible 36 sessions.
Patients were referred to CR by their physicians. Prior to beginning the program, patients were assessed by a registered nurse or exercise physiologist who collected demographic information and health history. In addition, a number of baseline assessments were conducted to determine each participant’s HRQL, knowledge of cardiac disease, and current dietary and physical activity practices. After completion of this initial meeting, patients joined one of the Phase-II CR supervised exercise classes. These classes took place three times per week for up to 36 sessions over a 3-month period.
The 1-hour classes consisted of monitored aerobic exercise and resistance training. Aerobic exercise included treadmill walking, stationary cycling, arm ergometry, and recumbent stepping. Resistance exercise focused on developing muscular strength and endurance in the arms, shoulders, and torso. Exercise intensity for both types of training was individualized for each patient based on the patient’s initial rating of perceived exertion (RPE) for each type of exercise (Noble, Borg, Jacobs, Ceci, & Kaiser, 1983). Exercise intensity was gradually increased throughout the 12-week program based on the patient’s reported RPE and cardiovascular response to exercise. Blood pressure and heart rate (via telemetry) were assessed and recorded before, during, and after each exercise session. In addition to the exercise classes, patients and significant others were encouraged to attend weekly educational classes on topics related to living a heart-healthy lifestyle.
Health-Related Quality of Life
HRQL was measured prior to the patient’s first exercise session and at 3 months and 1 year after the first exercise session. HRQL was assessed using the Medical Outcomes Survey Short Form 36 (SF-36), a generic, nondisease-specific measure of HRQL (Ware & Sherbourne, 1992). The SF-36 is a 36-item questionnaire that assesses eight health concepts: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health. Item scores for each health concept are totaled and the summed scores are translated to a scale of 0–100 with a higher score representing greater overall health status (McHorney, Ware, Lu, & Sherbourne, 1994). The SF-36 may be either self-administered or interview-assisted in person or by telephone. In this study, the SF-36 was self-administered. The SF-36 has demonstrated validity and reliability as a measure of HRQL in various disease populations, including cardiac patients (Ware, Snow, Kosinski, & Gandek, 1993).
Pearson correlation coefficients were calculated to determine the relationship between adherence to CR and achieved outcomes. Paired sample t-tests were performed to determine whether there was a difference in outcomes from baseline and the 3-month and 1-year follow-up for the total group. Adherence was based on the patient’s total sessions attended out of a possible 36 sessions. Statistical significance was p < .05.
Patient population demographics are provided in Table 1. The majority of the patients in this study were male (74.5%), and the majority of patients had the primary diagnosis of coronary artery bypass graft (67%). Patients attended, on average, 19 out of the 36 available Phase-II CR sessions.
Adherence Rate and HRQL
The relationship between adherence rate and HRQL achieved are presented in Table 2. No significant relationship was found between adherence and changes in any of the SF-36 components at all intervals.
The changes in HRQL from baseline to 3 months and 1 year for the total group are presented in Table 3. Patients’ HRQL significantly improved from baseline to 3 months and baseline to 1 year for all SF-36 components except general health. Patients improved significantly in physical functioning from 3 months to 1 year (p = .01).
The findings of this study suggest that the HRQL of participants in CR improves at 3 months and 1 year regardless of adherence level. However, as this study was retrospective in design, determining the reasons for this lack of relationship between adherence and HRQL improvements is not possible. The researchers were not able to control for factors that may have influenced patients’ HRQL after the patients dropped out of the program. These factors may vary from financial concerns to patients’ lack of motivation, health practices, and medical condition. For example, the authors received a follow-up SF-36 survey in which a patient had remarked that he had recently suffered a stroke and was not doing well. This patient’s medical condition at the time of this follow-up survey may have affected his response. Hence, future studies should control for such factors to clarify the relationship between adherence to CR and achieved outcomes.
Despite attending on average just over half (19 out of 36) of the possible Phase-II CR sessions, all patients’ HRQL improved from baseline to 3 months with improvement remaining statistically significant after 1 year (see Table 3). Indeed, all SF-36 constructs showed significant improvement except general health. The authors recognize that without a control group the improvement in HRQL cannot definitively be attributed to the CR program. However, for purposes of this correlational study, showing that HRQL improved over the observed time period made possible the determination that adherence to CR was not related to this benefit of participation. Similar studies using a control group have provided inconclusive evidence of the benefits in HRQL with CR participation, highlighting the need for further research to understand the effect CR has on HRQL (Goss, Epstein, & Maynard, 2002; Simchen, Naveh, Zitser-Gurevich, Brown, & Galai, 2001).
Much emphasis has been placed on helping cardiac patients adhere to the traditional 12-week, Phase II-CR program. However, many patients may benefit from programs that are shorter or longer. The traditional CR program should be closely examined and novel approaches should be explored. Hamm et al. (2004) recently examined a novel approach to CR that included only one supervised exercise session per week over a 52-week period. The results of the study demonstrated that 38 weeks of supervised and unsupervised exercise sessions significantly improved a number of selected clinical, physiologic, and psychological variables. In addition, Hevey et al. (2003) explored the difference between a 10-week (30 sessions) and a 4-week (20 sessions) CR program on various outcome measures. No difference was found between the two groups regarding improvements in exercise capacity and whether general health and well-being with both groups significantly improved in the measured outcomes. These studies demonstrate the need to further explore the most effective and beneficial CR program for all cardiac patients. In fact, the most effective program may be one that is adaptable to each individual patient’s needs, with program length and exercise-session frequency that is more flexible than in years past.
The patients in this CR population significantly improved in HRQL regardless of the number of CR sessions attended. Because the reasons for a lack of relationship between adherence and benefit of participation to CR were not determined in this study, future research is needed that systematically controls for factors that would influence health outcomes after patients drop out of, or complete, a CR program. In doing this, the best practice for the rehabilitation of cardiac patients post discharge may be more clearly defined.
About the Authors
Jeffrey L. Alexander, PhD, is an exercise specialist in the Department of Cardiac and Pulmonary Rehabilitation at Banner Baywood Heart Hospital, Mesa, AZ. Address correspondence to him at 6750 E. Baywood Ave., Mesa, AZ 85206; 480/854-5045 or Jeff.Alexander@bannerhealth.com.
Carolyn Wagner, BSN RN, is a cardiopulmonary rehabilitation nurse in the Department of Cardiac and Pulmonary Rehabilitation at Banner Baywood Heart Hospital, Mesa, AZ, 85206. E-mail: Carolyn.Wagner@bannerhealth.com.
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