Coronary heart disease (CHD) is a major cause of morbidity and mortality in Australia and is associated with significant cost.1 Australian guidelines recommend that all patients with an acute coronary syndrome (ACS) participate in secondary prevention,2 incorporating risk-factor management including lifestyle change and the use of vasoprotective medications. This is an effective means of extending overall survival, reducing the occurrence of non-fatal cardiovascular events, decreasing the need for coronary revascularisation and improving quality of life.3 Cardiac rehabilitation is a widely recognised form of secondary prevention,4 but participation rates are low (10%–30%)5,6 because of transport difficulties, work and social commitments, lack of perceived need,7 and functional impairment.8 Therefore, despite short-term benefits for attendees, large groups of patients are not benefiting, presenting an opportunity and challenge to improve overall CHD care.8
There are limited data reporting the risk-factor profile of patients not accessing cardiac rehabilitation,9 and, to the best of our knowledge, there are no studies reporting both risk-factor prevalence and knowledge of risk factors in this group. Knowledge of risk factors is an essential basis for active participation in lifestyle changes, medication adherence10,11 and improved quality of life12 — all important aspects of optimal secondary prevention. Patients’ knowledge may be suboptimal,13 and, in this study, we aimed to quantify the CHD risk profile and knowledge of risk factors of outpatients not accessing cardiac rehabilitation after an ACS.
All patients admitted to a metropolitan tertiary referral hospital in Sydney with an ACS between April 2003 and February 2004 were identified using diagnosis-related groups (DRG) codes14 for unstable angina (F72A, F72B), myocardial infarction (F41A, F41B, F60A, F60B) and chest pain (F74Z). Hospital medical records were reviewed to determine secondary prevention eligibility. Reasons for ineligibility included living more than 20 km from the hospital; insufficient understanding of English to give informed consent; and uncontrolled congestive heart failure, severe comorbidity, or death.
Of the total of 824 admissions, 378 patients (46%) were ineligible for participation in a formal cardiac rehabilitation program (reasons given in Box 1). All 446 eligible patients were contacted by mail and telephone within 12 months of admission and invited to volunteer for research investigating CHD prevention; 235 declined (reasons given in Box 1) and three were excluded because they had previously attended cardiac rehabilitation. Altogether, 208 patients attended for an assessment (Box 1), 64 of whom were about to commence cardiac rehabilitation (standard cardiac rehabilitation [SCR] group) and 144 were not (no cardiac rehabilitation [NCR] group). Reasons for not attending cardiac rehabilitation included: transport problems (19%); work commitments (16%); doing own exercise (8%); not interested (10%); and not referred (47% — due to patient/physician preference and/or scarcity of resources). Risk factors for all eligible patients who did not attend face-to-face assessment were extracted from medical records to permit comparison of risk factors with those who attended assessment.
CHD risk-factor prevalence and level, overall risk profile and knowledge of risk factors were evaluated during a face-to-face assessment at 4.5 ± 0.2 months (mean ± SEM) after admission for an ACS. For 83% of patients accessing standard cardiac rehabilitation, assessment was conducted before the initial appointment and commencement of cardiac rehabilitation. Lipids were measured on a fasting blood sample. Resting blood pressure was measured with an Omron automatic blood pressure monitor (Omron Healthcare Inc, Illinois, USA).15 Smoking status was measured by self-report and confirmed with the aid of a carbon monoxide meter (Air-Met Scientific Micro Smokerlyzer, Melbourne, Vic).16 Physical activity was assessed using the international 7-day physical activity recall questionnaire,17 and depressive mood was assessed using the cardiac depression scale.18 The Medical Outcome Short Form Health Survey (SF-36) (version 2)19,20 was used to assess quality of life, and socioeconomic status was compared between the groups using the socioeconomic index for areas scores (lower values represent regions of greater disadvantage).21
Cutoff points for determining the number of modifiable risk factors were:
total cholesterol level, > 4.0 mmol/L;
systolic blood pressure, ≥ 140 mmHg;
current smoking;
body mass index, ≥ 30 kg/m;
known diabetes; and
The LIPID risk score22 was used to calculate each patient’s relative cardiac risk. This score was developed for use in secondary prevention, and the aggregate score classifies patients as having low (score, ≤ 4), medium (5–6), high (7–9) or very high risk (≥ 10).
To assess knowledge of risk factors, patients were asked whether they could state any of their own heart disease risk factors and whether they knew the current nationally recommended levels for total cholesterol, blood pressure, physical activity and smoking. A history of hypercholesterolaemia and hypertension was recorded from each patient’s medical records, so that when comparing patients’ knowledge of their own risk factors with risk factor prevalence, we used either a total cholesterol or blood pressure level above the cutoff point, or a history of the risk factor, as the denominator.
Ethical approval for the study was obtained from the then Central Sydney Area Health Service, Concord (Repatriation General Hospital Zone) and the University of Sydney. All participants gave written informed consent.
Data were analysed using SPSS for Windows (version 12.01; SPSS Inc, Chicago, Ill, USA) and are presented as mean and SEM or as proportions. Differences in outcome measures between groups were compared using t tests for continuous variables and either χ2 tests or Fisher’s exact tests for proportions of categorical variables. Two-tailed P values of < 0.05 were considered significant.
Most of the patients were male, born in Australia and were not working (Box 2). Fewer patients in the NCR group than in the SCR group had undergone coronary revascularisation (56% v 86%; P < 0.001), and the mean (± SEM) time between ACS admission and risk-factor assessment was longer in the NCR group (6.3 ± 0.2 months) than the SCR group (3.3 ± 0.2 months). Socioeconomic status was not significantly different between the NCR and SCR groups. Fewer patients in the NCR group than in the SCR group reported taking a statin (69% v 83%, P = 0.02). Other cardiovascular medications were similar in the two groups (Box 3).
A significantly greater proportion of patients in the NCR group than the SCR group had total cholesterol levels > 4.0 mmol/L, low-density lipoprotein (LDL) cholesterol levels > 2.5 mmol/L, were physically inactive, obese, depressed, and current smokers (Box 4), and had four or more cardiac risk factors. The mean (± SEM) LDL cholesterol level, cardiac depression scale depression score, number of modifiable risk factors and LIPID score were also significantly greater in the NCR than the SCR group (Box 5). Further, the proportion of patients with a LIPID score ≥ 5 (medium-to-high risk) was significantly higher in the NCR than the SCR group (49% v 22%; P < 0.001). Quality of life measured using the SF-36 questionnaire was significantly worse in the NCR group compared with the SCR group in the dimensions: physical functioning (71.6 ± 1.5 v 76.5 ± 2.0; P = 0.008); vitality (50.5 ± 1.5 v 57.3 ± 2.6; P = 0.04); and role-emotional (78.3 ± 2.9 v 93.7 ± 1.8; P = 0.001).
Of the patients in the total cohort with at least one modifiable risk factor, most (137/194, 71%) were unable to state any risk factors. A significantly greater proportion of patients in the NCR group than in the SCR group were unable to state any of their risk factors (75% v 58%; P = 0.013). Also, significantly fewer patients in the NCR group than the SCR group could state nationally recommended targets for total cholesterol level, blood pressure and physical activity (Box 6).
Of the 235 eligible patients who declined attending for assessment, significantly fewer had experienced myocardial infarction than patients in the NCR group (20% v 58%; P < 0.001). However, there was no significant difference between those who declined assessment and those in the NCR group in the proportion with a total cholesterol level > 4.0 mmol/L (73% v 78%); systolic blood pressure ≥ 140 mmHg (53% v 43%); diabetes (28% v 28%); current smoker (21% v 21%); mean (± SEM) total cholesterol level (4.8 ± 0.1 v 4.7 ± 0.1 mmol/L) or mean (± SEM) systolic blood pressure (137.1 ± 1.5 v 136.9 1.2 mmHg).
Our study quantifies the CHD risk profile and risk-factor knowledge of patients not accessing cardiac rehabilitation (NCR group) after hospital admission for an ACS. Such patients had a more adverse risk-factor profile and poorer knowledge of cardiac risk factors than those about to commence standard cardiac rehabilitation (SCR group). Although serum cholesterol level is arguably the most important risk factor, fewer patients in the NCR group could state the recommended level and were more likely to have a high total cholesterol level than those in the SCR group. The difference in total cholesterol level between the two groups equates to a predicted increase in CHD risk of about 24%.23
Patients in the NCR group were more likely to be physically inactive, a trait that clusters with other risk factors such as obesity, smoking or depression.1 Patients may decline to take part in an exercise-based program fearing overexertion, or because of self-consciousness resulting from inactivity or obesity. Therefore, an exercise-based approach may not be the most appropriate form of secondary prevention for all patients.
Surprisingly, ACS survivors had very poor knowledge of cardiac risk factors. Over 70% of patients were unable to state any of their own modifiable risk factors. In agreement with our study, a point prevalence study investigating patients’ awareness of risk factors found that only 14/71 patients (20%) could define a cardiac risk factor and, overall, patients had “very little understanding” of their own risk factors.13 Therefore, information about risk factors is not being processed, retained or provided during or after admission. We also found that risk-factor knowledge of patients in the NCR group was significantly inferior to those in the SCG group, while at the same time, the number of risk factors and the risk-factor level was significantly worse.
This highlights a crucial gap in the delivery of care — the patients with the greatest need and poorest knowledge are not accessing formal secondary prevention. Risk factor knowledge has been shown to correlate with greater adherence to lifestyle changes,11 enhanced orientation of patients towards activity, and better health status and quality of life.12 Alternative secondary prevention programs, such as the COACH study,24 or a modular program25 for patients who do not access exercise-based cardiac rehabilitation could improve outcomes by closing this gap in knowledge.
2 Demographic and clinical characteristics of patients with an acute coronary syndrome not attending (NCR group) or attending (SCR group) cardiac rehabilitation. Data are number (%) unless otherwise indicated
History of transient ischaemic attack/cerebrovascular accident/peripheral vascular disease |
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3 Medications taken by patients not attending (NCR group) or attending (SCR group) standard cardiac rehabilitation after an acute coronary syndrome
4 Proportion of patients with various risk factors not attending (NRC group) or attending (SCR group) cardiac rehabilitation after an acute coronary syndrome
* P < 0.05; † P < 0.001: for no cardiac rehabilitation (NCR group) v standard cardiac rehabilitation (SCR group).
5 Modifiable cardiac risk factors in patients not attending (NCR group) or attending (SCR group) cardiac rehabilitation after an acute coronary syndrome. Data are mean ± SEM or number (%)
Received 20 March 2006, accepted 4 September 2006
Abstract
Objective: To document the risk-factor profile and risk-factor knowledge of patients with an acute coronary syndrome (ACS) not attending standard cardiac rehabilitation.
Design and setting: Cross-sectional comparison in a tertiary hospital.
Participants: Patients admitted to hospital with an ACS, residing within 20 km of the hospital, and without severe comorbidity who did not access cardiac rehabilitation (NCR) were compared with a group about to commence standard cardiac rehabilitation (SCR).
Main outcome measures: Risk-factor profile, knowledge of risk factors via face-to-face assessment, quality of life.
Results: Of the 446 patients eligible for cardiac rehabilitation, 208 attended for assessment (NCR: n = 144; SCR: n = 64). The NCR group had higher mean (± SEM) low-density lipoprotein (LDL) cholesterol levels (2.6 ± 0.1 v 2.3 ± 0.1; P = 0.02), and were more likely than the SCR group to have a total cholesterol level of > 4.0 mmol/L (78% v 53%; P < 0.001) and an LDL cholesterol level > 2.5 mmol/L (47% v 25%; P = 0.01). They were more likely than the SCR group to be physically inactive (77% v 22%; P < 0.001); obese (46% v 33%; P = 0.04); depressed (21% v 5%; P < 0.001); or current smokers (21% v 1%; P < 0.001). Compared with the SCR group, the NCR group also had higher risk scores (LIPID risk score) (4.5 v 2.1; P < 0.001); lower quality of life (Medical Outcome Short Form [SF-36] Health Survey); and significantly poorer knowledge of risk factors. Among patients with at least two modifiable cardiac risk factors, the NCR group were less likely than the SCR group to be able to state at least one risk factor (24% v 38%; P < 0.001).
Conclusions: Patients not participating in cardiac rehabilitation after an ACS have more adverse risk profiles and poorer knowledge of risk factors compared with those about to commence cardiac rehabilitation. Alternate models for secondary prevention are required to improve health outcomes in patients not attending cardiac rehabilitation.