A Transitional Care Model for Patients With Acute Coronary Syndrome

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The American Journal of Accountable Care, June 2014, Volume 2, Issue 2

This study suggests that the Bridging the Discharge Gap Effectively (BRIDGE) program can help decrease the number of hospital readmissions in patients with acute coronary syndrome that cause unnecessary and substantial healthcare systems costs.

ABSTRACT

IMPORTANCE: Hospital readmissions place a substantial burden on the US healthcare system, especially those related to cardiovascular disease. Patients with acute coronary syndrome (ACS) constitute many of these readmissions, yet little is known about reducing such events.

OBJECTIVES: This study aimed to measure the effectiveness of the Bridging the Discharge Gap Effectively (BRIDGE) program in reducing readmissions and improving medication persistence in patients with ACS.

DESIGN: This was a retrospective outcomes study that used consecutive data for all patients referred to the BRIDGE program between March 2008 and March 2009.

SETTING: Ambulatory visit post-discharge from an academic hospital.

PARTICIPANTS: A total of 424 patients were referred to the BRIDGE program. ACS comprised 25.2% (n = 107) of the diagnoses. Patients were excluded if they died or were rehospitalized prior to their scheduled BRIDGE appointment (n = 9, 8.4%).The final study sample included 80 patients after excluding patients with missing data (n = 18, 18.4%).

INTERVENTION: BRIDGE is a nurse practitioner—led model for providing transitional care to cardiac patients.The intervention consists of a 1-time visit within 14 days of discharge. Patients received AHA/ACCF guideline-based care, examinations, education, follow-up, and referrals.

MAIN OUTCOME MEASURES: Prior to data collection, it was hypothesized that patients who attended BRIDGE would have lower 30-day readmission rates and superior 6-month medication persistence rates over nonparticipants (ie, follow-up only with primary care providers or cardiologists).

RESULTS: Of 80 patients, 77.5% (n = 62) attended. Their mean age was 62.5 years, 58.7% were female, and 86.3% were white. Patients who attended BRIDGE had lower rates of readmission at 30 (9.7% vs 27.8%, P = .112), 60 (11.3% vs 38.9%, P = .012), 90 (16.1% vs 38.9%, P = .052), and 180 (27.4% vs 50.0%, P = .072) days postdischarge compared with nonattenders.There were no significant differences between groups in medication persistence 6 months after discharge.

CONCLUSIONS: Patients who attended their BRIDGE appointment had fewer readmissions than patients who received usual care. Further, these reductions were not explained by better medication persistence. Models such as this should be developed and analyzed across institutions and patient types to ensure patient safety at home after hospital discharge and reduce excessive and unnecessary health-system costs.It was estimated that 15.4 million Americans suffered from coronary heart disease between 2007 and 2010, and nearly 1 635,000 more would have a new coronary event. Of the latter, 419,100 will likely survive and approximately 67% of those (280,000) will suffer a recurrent event warranting rehospitalization (not including those who will have a silent event).1 Despite these projections, little is known about the circumstances culminating in a hospital readmission for patients with acute coronary syndrome (ACS). Possible contributors, however, have been speculated to include premature discharge, lack of prompt access to cardiology follow-up after hospital discharge,2 insufficient discharge education, lack of patient understanding of education provided, and poor patient and provider adherence to American Heart Association/American College of Cardiology Foundation (AHA/ACCF) guidelines.3 Whatever the cause of these hospital readmissions, especially those deemed avoidable,4 they place a substantial burden on an already stressed US healthcare system.5 To address these high rates of readmission, many clinical scientists and care providers are looking to new models of care that focus specifically on the transition period between hospital discharge and home.

Transitional care begins prior to hospital discharge and terminates once an outpatient care team has seen the patient and assumed care responsibility. Most transitional care models are designed around direct patient assessment, diagnosis, treatment, and education during this interim phase.6-9 This is achieved by facilitating communication among providers, improving discharge education and medication management, resolving outstanding diagnostics, and instructing patients when to seek care.10

Healthcare providers have long recognized the consequences of poor patient follow-up, but lack of provider accountability between discharge and ambulatory care follow-up has allowed a gap in care transitions to go largely unchecked.11 As an example, Jencks and colleagues5 reported that 50.2% of Medicare patients rehospitalized within 30 days of discharge had no record of being seen by a healthcare provider postdischarge. One consequence of such oversight is the rising number of potentially preventable hospital readmissions.12 Initially, the aim of reporting hospital readmission rates was to draw attention to the dilemma and allow patients to make informed choices about where to seek care.13 Later, readmission rates became part of pay-for-performance programs.14 Now, as a result of the Patient Protection and Affordable Care Act (ACA), hospitals with above-average readmission rates will be penalized with a reduction in the percentage of their Medicare reimbursement. Initial fines were imposed in 2013 and levied against 2012 readmission rates.

We developed the Bridging the Discharge Gap Effectively (BRIDGE) program to facilitate timely postdischarge care for patients discharged with a cardiac diagnosis. Operating since 2008, BRIDGE provides a 1-time ambulatory transitional care visit within 14 days of discharge, and stresses the importance of developing trusting relationships between patients and providers.15 The BRIDGE clinic is staffed by 5 specialty-certified cardiovascular nurse practitioners (NPs) who function in colaboration with the discharging cardiologist. The goal of the NPs is to eliminate many of the aforementioned contributors to hospital readmissions by conducting thorough examinations, reviewing diagnostic tests postdischarge, evaluating response to treatment, performing medication reconciliation, making therapeutic adjustments when necessary, and ensuring that appropriate follow-up and referrals are scheduled. The NPs tailor education about the individual’s event, condition, disease process, and signs and symptoms that should trigger a call to a physician or an emergency department visit. The BRIDGE visit functions as an extension of the hospital discharge team, differing from usual care in 3 distinct ways: (1) the BRIDGE clinic ensures that the time between a patient’s hospital discharge to their first outpatient follow-up is no longer than 14 days; (2) the visit with a NP, while providing traditional evaluation and treatment, emphasizes education and support; and (3) patients are seen by NPs who are integrated within the health system and better able to facilitate and coordinate care within that system compared with those external to the system.

This study aimed to measure the effectiveness of the BRIDGE program by comparing the 30-day to 180-day readmission rates for ACS patients who attended BRIDGE with those who chose not to attend in lieu of usual care. Additionally, it aimed to determine whether medication persistence contributed to the readmission rates. It was hypothesized that patients who attended BRIDGE would have lower 30-day readmission rates and superior 6-month medication persistence rates over nonparticipants.

Methods

This was a retrospective study using consecutive data (extracted from an electronic medical record) for all patients referred to the BRIDGE program in a deidentified clinical database. The Human Subjects Internal Review Board of the University of Michigan Medical Center approved this study (HUM00035421).

All patients discharged with a diagnosis of ACS (acute myocardial infarction or unstable angina) from the inpatient adult cardiology service between March 30, 2008, and March 30, 2009, were eligible for this study. Referrals were made to the BRIDGE program based on the lack of availability of a cardiology or primary care follow-up appointment within 14 days of discharge. Patients included in the analysis were divided into 2 cohorts: those who were referred and attended (“attenders”) and those who were referred and did not attend (“nonattenders”). Patients were excluded from the study if they became pregnant, sought follow-up outside the institution, or died within 30 days of discharge. The Social Security Death Index was queried for patients lost to follow-up; only the result of this query was recorded.

The study cohort (Figure 1) included 424 patients referred to the BRIDGE program. ACS comprised 25.2% (n = 107) of the diagnoses referred. Patients were further excluded if they died or were rehospitalized prior to their scheduled BRIDGE appointment (n = 9; 8.4%). The final study sample included 80 patients after excluding patients with missing variables (n = 18; 18.4%).

Instruments

Two principal instruments were used to describe patients’ overall state of health. The first measure, the Charlson Comorbidity Index (CCI), quantified the combined effects of 19 comorbid conditions on mortality.16 Tested across a variety of populations, the CCI has consistently proved valid for predicting mortality.16-18 The second measure, the GRACE Risk Model for Discharge, predicted the risk of death in patients with ACS from hospital discharge to 6 months out19 with excellent discriminatory and predictive validity (C statistic, 0.70-0.80).20,21

Data Analysis

Data were analyzed using SPSS 18.0 (IBM, Armonk, New York). All variables were assessed for compliance with statistical assumptions. Missing data were excluded from the sample.

Baseline equivalencies were assessed for all demographic variables, comorbidities, CCI scores, and GRACE risk scores. Associations between variables were assessed with Pearson’s correlation coefficient. Independent student t tests and χ2 were used to compare differences between the BRIDGE intervention group and the usual care group. Pearson’s χ2 test for significance was reported except in cases where the expected count would violate an underlying assumption; in those cases, Fisher’s exact test was reported. Hierarchical logistic regression models were used to evaluate whether BRIDGE attendance influenced readmissions and/or medication persistence, after adjusting for comorbidities (CCI) and severity of events (GRACE). ORs and 95% CIs were reported for all independent variables. The significance level was set at .05 for all analyses.

Readmission rate. The hospital readmission rate was calculated as the number of patients discharged from the hospital with a diagnosis of an ACS event and readmitted within 30, 60, 90, or 180 days, divided by the total number of people who were discharged alive with the same diagnosis.5 The BRIDGE and non-BRIDGE— specific rates of readmission were calculated as the total number of readmissions for the BRIDGE and non-BRIDGE groups divided by the total number of subjects in each group. Only the first readmission following discharge for an ACS event was counted.

Medication persistence. Medication persistence was defined as self-reported continued use of prescribed AHA/ACCF-recommended pharmacotherapy regimens of β-blockers, angiotensin-converting enzyme (ACE) inhibitors (or angiotensin II receptor blockers [ARBs]), aspirin, statins, or clopidogrel at 6 months, postdischarge. Six-month persistence rates were determined by comparing self-reported medication regimens from the most complete cardiology or primary care follow-up notes at 6 months, postdischarge (no more than 2 weeks before and no more than 1 month beyond the 6-month discharge date) to the medication regimen prescribed at discharge. Six-month medication persistence rates for each drug and for the 4 (β-blockers, ACE inhibitors [or ARBs], aspirin, statins) and 5 (β-blockers, ACE inhibitors [or ARBs], aspirin, statins, plus clopidogrel) drug combination regimens were compared between BRIDGE attendees and nonattendees. This methodology is consistent with the methodology employed by the GRACE Registry.22 Patients with known contraindications or hypersensitivity reactions to certain medications, such that they could not be prescribed or continued, were excluded.

Results

Of 107 ACS patients discharged from the study hospital and referred to the BRIDGE program, 80 were included in the final readmission analysis. To isolate the BRIDGE effect, patients who died or were readmitted prior to their scheduled appointment were excluded, as were patients with missing data (n = 27; Figure 1). Excluded patients, compared with patients remaining in the study, were noted to have higher CCI and GRACE risk scores, suggesting that these patients either had more comorbid conditions, worse events, or both.

The mean age of the final sample was 62.4 years. The majority (58.8%) were female, and white (86.3%), with a median length of initial hospital stay ranging from 2 to 4 days. Table 1 shows a comparison of patients who attended BRIDGE versus non-attenders. With the exception of a higher percentage of dyslipidemia among BRIDGE users, there were no significant differences between the 2 groups.

Attendance

As seen in Table 1, 77.5% (n = 62) of the patients referred to the BRIDGE program attended their scheduled appointment. The median time from discharge to attending a BRIDGE program appointment was 15 days (range, 11-20 days). The time elapsed between discharge and being seen by any medical provider (considered usual care) was 20 days longer for patients who did not attend BRIDGE. However, patients who did not attend BRIDGE were seen by cardiology sooner (31 days vs 59 days; P <.05) than attenders. Patients who missed or cancelled their BRIDGE appointment (n = 58) were contacted by phone to ascertain the reason. Approximately one-third (34.5%) reported that they were able to get an earlier appointment with either cardiology or their primary care provider. Other reasons for not attending included not wanting the appointment (17.2%), no-show (12.1%), problems with appointment location (5.2%), rehospitalization (5.2%), schedule conflict (5.2%), and other unspecified reasons (19.0%).

Readmissions

It was hypothesized that patients who were referred and chose to attend the BRIDGE program would have lower readmission rates than patients who received usual care. In fact, as shown in Figure 2, patients who attended the BRIDGE program had lower rates of readmission at 30, 60, 90, and 180 days after hospital discharge for an ACS event than did nonattenders, but only 60-day data were significantly different between the groups.

Patients participating in the BRIDGE program were .138 to .378 times less likely to be readmitted compared with those who received usual care (Table 2). The maximum benefit was observed at 60 days postdischarge, though at all points post discharge, BRIDGE attenders were less likely to be readmitted. Data were subsequently and independently risk adjusted both for CCI and GRACE risk scores, as these measures have a linear relationship (r = .812). Both models (CCI and GRACE) fit the data equally well with Hosmer-Lemeshow goodness of fit test significance levels between 0.447 and 0.915.

Medication Persistence

To explicate why patients who participated in the BRIDGE program had lower readmission rates, we further analyzed whether patients seen in the BRIDGE program were more likely to adhere to their prescribed AHA/ACCF-recommended pharmacotherapy regimens. Given the breadth of literature suggesting that transitional care models with NPs fill a critical gap in care delivery to effect outcomes,23,24 it was hypothesized that patients who participated in the BRIDGE program would have higher medication persistence rates at 6 months than individuals who did not participate.

Overall rates of medication prescribing at discharge for secondary prevention in the study cohort exceeded published rates for aspirin, β-blockers, and statins.25,26 Table 3 describes patterns of attendance by medications prescribed at discharge and patterns of persistence with medications 6 months after discharge. All patients referred to BRIDGE without an early adverse event (n = 98) were included in this analysis. Patients with missing medication data were excluded at each time point such that at 6-month follow-up, sample sizes were smaller and varied by group.

Nearly all patients discharged with ACS were prescribed aspirin (97.9%) and statins (94.8%), and use of β-blockers (88.7%) and ACE inhibitors (or ARBs; 75.3%) was high compared with published literature.26,27 Of patients meeting the criteria for clopidogrel, 75.0% received a prescription at discharge. Most subjects remained on their prescribed pharmacotherapy regimens 6 months after discharge. However, there were no differences in medication persistence between BRIDGE participants or participants receiving usual care 6 months after discharge.

Logistic regression was used to predict the likelihood of medication persistence at 6 months after hospital discharge. The analysis was limited by the number of patients for which there were medication persistence data available. Because of the small sample size, it was necessary to test a series of models rather than a single model. Therefore, 3 series of analyses were performed (BRIDGE attendance; BRIDGE attendance adjusted for CCI; and BRIDGE attendance adjusted for GRACE risk score). Each series tested the likelihood of medication persistence to aspirin, ß-blockers, ACE-inhibitors, statins, and clopidogrel individually and to the 4- and 5-drug combined pharmacotherapy regimens of aspirin, ß-blockers, ACE inhibitors, and statins (4- drug regimen) plus clopidogrel (5-drug regimen). Only 4 of the 21 models tested were predictive of medication persistence at 6 months: ß-blockers or ACE-inhibitors adjusted for either the CCI or GRACE risk score. For ß-blockers, the addition of the CCI to attendance explained between 22.9% (Cox and Snell R2) and 47.8% (Nagelkerke R2) of the variance in persistence. Likewise, testing attendance with the GRACE risk score explained between 25.4% (Cox and Snell R2) and 53.1% (Nagelkerke R2) of the variance. The ACE-inhibitor model adjusted for the CCI explained between 25.0% (Cox and Snell R2) and 39.0% (Nagel- kerke R2) of the variance in persistence; and in combination with the GRACE risk score explained between 31.7% (Cox and Snell R2) and 49.5% (Nagelkerke R2) of the variance.

Discussion

This study was designed to measure the effectiveness of the BRIDGE program in reducing hospital readmission rates for ACS patients. It was hypothesized that compared with patients who had usual care, BRIDGE attenders would have lower rates of hospital readmissions. BRIDGE attenders were seen at a median of 15 days postdischarge--the same timeframe in which nonattenders were seen by their primary care providers, but 16 days earlier than nonattenders were seen by a cardiologist. The NP-driven, single-dose, transitional care program was a successful strategy to lower all-cause hospital readmissions for ACS patients. Even after adjustments for severity of illness and severity of event, patients who chose to attend their BRIDGE appointments fared better than patients who received usual care. Although this study was designed to address readmissions within 30 days of hospital discharge, the maximum benefit was observed at 60 days postdischarge, with a positive trend at all other time points.

Reductions in readmissions cannot be explained simply by better medication persistence for those who attended BRIDGE. There were no significant differences in 6-month medication persistence for any single medication (aspirin, β-blocker, ACE inhibitor, statin, clopidogrel) or combined regimen. With the exception of risk-adjusted β-blocker and ACE inhibitor models, no other models were predictive of medication persistence 6 months after discharge. Further research is thus needed to more fully understand what elements of the BRIDGE program contribute to its success.

Limitations

There are some limitations that should be considered with regard to this study. Study data were collected retrospectively, and thus, causality should not be assumed. As the study also lacks randomization, the results may not be generalizable. The sample size was small, with readmission rates as low as 9.7%, such that there were insufficient outcomes to adequately power a multiple regression analysis. Despite this, significantly lower readmission rates were found at both 60- and 90-day postdischarge points.

Optimal time to follow-up was another limitation of this study. When the BRIDGE program began (2008), postdischarge follow-up within 14 days was reasonable. However, this design was problematic for assessing 30-day outcomes, as the measurement period was not truly 30 days, but rather only the 14 days between BRIDGE appointments and the 30 days postdischarge date. A further limitation of this study was the use of self-report data for medication persistence. Information as to whether medication omissions or discontinuation were the result of a patient or provider decision was inconsistently documented. Thus, it is not possible to determine whether this over or underestimates the potential benefits of BRIDGE. A more formal study is needed to investigate these findings.

Conclusions

The general cardiology BRIDGE program is a novel and effective model for providing transitional care and lowering all-cause hospital readmissions for ACS patients. The NPs provide a high level of service in ensuring the health of their patients, providing education to the patients and their families, reconciling medications, and communicating with the patient’s discharge team and outpatient care provider. Even after adjustments for severity of illness and severity of event, patients who chose to attend their BRIDGE appointments had lower readmission rates at 30, 60, 90, and 180 days postdischarge than those with usual care. Furthermore, these reductions were not explained by better medication persistence. Though the relative value of this NP model of early postdischarge transitional care compared with a timely primary care or cardiology physician visit remains to be seen, models such as this should be developed and analyzed across institutions and patient types (diagnoses) to maintain patient safety at home after hospital discharge and reduce excessive and unnecessary health-system costs.Acknowledgments: The authors would like to thank Eva Kline-Rogers, MS, RN, NP (University of Michigan, MCORRP), and Cydni A. Smith, BA (University of Michigan School of Pub- lic Health); Redah Mahmood, MD; Daniel Montgomery, MS; Ra- chel Sylvester, BS (MCORRP); and the student data abstractors who helped with this study.

Author Affiliations: Eastern Michigan University, Ypsilanti (SB); University of Michigan School of Nursing, Ann Arbor (BLB, SJP); University of Michigan School of Public Health, Ann Ar- bor (JW); Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor (KAE, MR).

Author Disclosures: The authors report no relationship or finan- cial interest with any entity that would pose a conflict of interest with the subject matter of this article. AHA Predoctoral Fellow- ship funded Sherry Bumpus to complete doctoral coursework and provided dissertation support. Dr Rubenfire had full access to all the data in the study and takes responsibility for the integri- ty of the data and the accuracy of the data analysis.

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