Trends in Referral to Cardiac Rehabilitation After Myocardial Infarction

Abstract

To the Editor: Cardiac rehabilitation (CR) is a guideline-recommended therapy that reduces mortality after acute myocar-dial infarction (MI) (1). However, it is notoriously underutilized. Between 2000 and 2007, only 56% of eligible patients were referred to CR (1,2). In 2007, professional societies established CR referral from inpatient settings as a performance measure for acute MI (3,4). We examined whether CR referral has changed since 2007 by using data from the National Cardiovascular Data Registry Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With the Guidelines Program (ACTION Registry– GWTG) (www.ncdr.com/webncdr/ACTION/Default.aspx). We evaluated patients admitted with a primary diagnosis of ST-segment or non–ST-segment MI from January 1, 2007, through June 30, 2012, who were discharged from the hospital and had CR referral data (Online Fig. 1). CR referral was defined as " an official communication between the health care provider and the patient to recommend and carry out a referral order to an early outpatient CR program. This includes the provision of all necessary information to the patient that will allow the patient to enroll in an early outpatient CR program. This also includes a communication between the health care provider or health care system and the CR program that includes the patient's referral information for the program. A hospital discharge summary or office note may potentially be formatted to include the necessary patient informa-tion. " Ineligibility was defined as documented patient-based bar-riers, patient-based criteria, or healthcare system barriers. Covariates included age, sex, race/ethnicity, insurance type, body mass index, current/recent smoking, hypertension, dyslipidemia, diabetes, current dialysis, previous MI, previous percutaneous cor-onary intervention (PCI), previous coronary artery bypass graft surgery (CABG), previous stroke, peripheral arterial disease, length of stay, ST-segment elevation MI on admission electrocardiogram, in-hospital PCI, in-hospital CABG, in-hospital catheterization, left ventricular ejection fraction, in-hospital cardiogenic shock, in-hospital heart failure, in-hospital major bleeding, hospital region (West, Northeast, Midwest, or South), teaching hospital status, and hospital bed size. Multivariate predictors of CR referral were estimated by using a generalized estimating equations logistic regression model with backward selection (p < 0.05). The model was implemented with empirical (sandwich) SE estimates and was adjusted for clustering of observations from the same hospital. We also conducted mul-tivariate analyses to estimate the odds of CR referral in each year (compared with 2007). Missing data (<1.5% for all covariates) were imputed by using standard techniques. All analyses were performed by using SAS version 9.2 a total of 329,698 registry patients with acute MI were discharged from participating hospitals with CR referral data. Of these, 301,247 patients (91.4%) from 624 hospitals were reported eligible for CR (Online Table 1); 28,451 (8.6%) were reported ineligible. From 2007 to 2012, CR referral increased by approximately 8% (from 72.9% to 80.7%; p < 0.0001 for trend) (Fig. 1). After multivariate adjustment, independent patient-level pre-dictors of CR referral included age, male sex, white race, body mass index, dyslipidemia, not having diabetes mellitus, not cur-rently on dialysis, no previous PCI, ST-segment elevation MI at admission, in-hospital catheterization, in-hospital PCI, in-hospital CABG, mild left ventricular systolic dysfunction, and length of stay (Online Table 2). Independent hospital-level predictors of CR referral included hospital in Midwest region, hospital bed size, and nonacademic hospital. After adjustment for multivariate pre-dictors of CR referral, referral was significantly greater in 2011 (odds ratio: 1.38 [95% confidence interval: 1.02 to 1.88]) and 2012 (odds ratio: 1.57 [95% confidence interval: 1.15 to 2.14]) compared with 2007 (Fig. 1). CR referral improved across sex and racial/ethnic groups but remained highest in male subjects and white subjects (Online Table 3). For hospitals in the lowest quartile of adherence to American College of Cardiology/American Heart Association 2008 performance measures (other than CR referral) (4), referral increased from 54% in 2007 to 64% in 2011. This rate is still significantly behind the 87% referral rate for the highest quality quartile hospitals in 2007 and 2011. We note several limitations. First, ACTION Registry–GWTG is a voluntary registry and may not be representative of hospitals lacking the resources or desire to contribute. Our results may overestimate referral to CR and may not be fully generalizable. Data are drawn solely from inpatient medical records abstracted for the registry. Misclassification of CR eligibility could have occurred. The registry's liberal definition of referral may over-estimate meaningful referral (3). Finally, interhospital variation in what constitutes CR referral and eligibility may be present. In summary, referral to CR has significantly increased since its introduction as a quality measure in 2007, with 81% of eligible pa-tients now being referred. Nonetheless, referral rates remain below achievable benchmarks. Compared with other acute MI discharge performance measures, CR referral has the lowest adherence, with measures such as aspirin prescription, beta-blocker prescription, and smoking cessation counseling achieving adherence in 95% of patients (5). Improvement strategies may include identifying key personnel to direct the process of introducing CR in the inpatient setting and developing systems for automatic referral (1).