Clinical and economic outcomes among hospitalized patients with acute coronary syndrome: an analysis of a national representative Medicare population

Challenges in Implementation of Institutional Protocols for Patients With Acute Coronary Syndrome

The diagnosis of acute coronary syndrome (ACS) encompasses ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation ACS (non-STEMI and unstable angina). In recent years, there have been improvements in the rates of death, cardiogenic shock, and recurrent myocardial infarction in patients with ACS, primarily due to the introduction of new pharmacological and interventional therapies, as well as the introduction of and adherence to new treatment guidelines. However, ACS still represents a considerable public health burden. Treatment recommendations for STEMI and non-ST-segment elevation differ and there is wide variation in practice patterns and adherence among and within hospitals especially for the latter diagnosis. Adoption of institutional protocols may help decrease variability and improve quality of care, efficiency, and, ultimately, patient outcomes. This report discusses the process of developing and implementing institutional protocols for patients with ACS, from initial medical contact to discharge and beyond.

Cost-utility analysis of physician-pharmacist collaborative intervention for treating hypertension compared with usual care

OBJECTIVE

To estimate long-term costs and outcomes attributable to a physician-pharmacist collaborative intervention compared with physician management alone for treating essential hypertension.

METHODS

A Markov model cohort simulation with a 6-month cycle length to predict acute coronary syndrome, stroke, and heart failure throughout lifetime was performed. A cohort of 399 patients was obtained from two prospective, cluster randomized controlled clinical trials implementing physician-pharmacist collaborative interventions in community-based medical offices in the Midwest, USA. Framingham risk equations and other algorithms were used to predict the vascular diseases. SBP reduction due to the interventions deteriorated until 5 years. Direct medical costs using a payer perspective were adjusted to 2015 dollar value, and the main outcome was quality-adjusted life years (QALYs); both were discounted at 3%. The intervention costs were estimated from the trials, whereas the remaining parameters were from published studies. A series of sensitivity analyses including changing patient risks of vascular diseases, probabilistic sensitivity analysis, and a cost-effectiveness acceptability curve were performed.

RESULTS

The lifetime incremental costs were $26 807.83 per QALY (QALYs gained = 0.14). The intervention provided the greatest benefit for the high-risk patients, moderate benefit for the trial patients, and the lowest benefit for the low-risk patients. If a payer is willing to pay $50 000 per QALY gained, in 48.6% of the time the intervention would be cost-effective.

CONCLUSION

Team-based care such as a physician-pharmacist collaboration appears to be a cost-effective strategy for treating hypertension. The intervention is most cost-effective for high-risk patients.

Glycated hemoglobin level is an independent predictor of major adverse cardiac events after nonfatal acute myocardial infarction in nondiabetic patients: A retrospective observational study

The effect of glycemic control on the prognosis of nondiabetic patients after acute myocardial infarction (AMI) remains uncertain. We investigated whether glycated hemoglobin (HbA1c) is associated with adverse outcomes after AMI in nondiabetic patients. In this observational study, we enrolled nondiabetic patients with AMI in the emergency department of 2 medical centers from January 2011 to September 2014. All patients received primary percutaneous coronary intervention and were divided into 4 groups according to the interquartile range of average HbA1c level (Group I, ≤5.6%; Group II, 5.6%-5.8%; Group III, 5.8%-6.0%; and Group IV, >6.0%). Multivariate logistic analysis was performed to estimate the correlation of HbA1c with major adverse cardiac events (MACEs) after AMI. In total, 267 eligible patients were enrolled; 48 patients (18%) developed MACEs within a median follow-up of 178 days. Univariate analysis showed HbA1c > 6.0%, with a higher risk of MACEs in Group IV than in Group I (odds ratio [OR]: 2.733; 95% confidence interval [CI]: 1.123-6.651 vs OR: 1.511; 95% CI: 0.595-3.835). Multivariate analysis revealed an approximately 3.8 times higher risk of MACEs in Group IV than in Group I (OR: 3.769; 95% CI: 1.30-10.86). The HbA1 level is a significant predictor of MACEs after AMI in nondiabetic patients.

Association of Patient Enrollment in Medicare Part D With Outcomes After Acute Myocardial Infarction

Background—

Little is known about whether enrollment versus nonenrollment in Medicare’s prescription drug plan (Part D) is associated with better outcomes after acute myocardial infarction (AMI).

Methods and Results—

Using Medicare records linked to Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines, we identified 59 149 Medicare beneficiaries (age ≥65 years) discharged after AMI between January 2007 and December 2010. We described trends in Medicare Part D enrollment, and compared the following 30-day and 1-year outcomes: all-cause death, all-cause readmissions, and major adverse cardiac events (a composite of all-cause death or readmission for AMI or stroke) between Part D enrollees and nonenrollees, after adjustment for patient and hospital factors. From 2007 to 2010, 29 264 (49.5%) patients with AMI enrolled in Medicare were also participating in Part D by hospital discharge. All-cause 30-day death was more common among enrollees versus nonenrollees (4.0% versus 3.3%), but this difference was not statistically significant after multivariable adjustment (adjusted hazard ratio, 1.06 [95% confidence interval, 0.97–1.17]). Enrollees also had higher unadjusted risks of 30-day all-cause readmissions or major adverse cardiac events, and 1-year mortality, all-cause readmissions, or major adverse cardiac events, but these were attenuated after multivariable adjustment. Adherence to key secondary prevention medications (statins, β-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and P2Y 12 antagonists) remained low (range, 55%–64%) at 1 year post discharge among Part D enrollees.

Conclusions—

Only half of Medicare-insured patients with AMI were enrolled in Part D by hospital discharge, and their 30-day and 1-year adjusted outcomes did not differ substantially from nonenrollees. There remain opportunities for improvement in medication adherence among patients with prescription drug coverage.

Medical costs associated with cardiovascular events among high-risk patients with hyperlipidemia

OBJECTIVES

This study descriptively examined acute and longer term direct medical costs associated with a major cardiovascular (CV) event among high-risk coronary heart disease risk-equivalent (CHD-RE) patients. It also gives a firsthand look at fatal versus nonfatal CV events.

METHODS

The MarketScan(®) Commercial Claims and Encounters Database was used to identify adults with a CV event in 2006-2012 with hyperlipidemia or lipid-lowering therapy use in the 18 months prior to one of the following inpatient CV events: myocardial infarction, ischemic stroke, unstable angina, transient ischemic attack, percutaneous coronary intervention, or coronary artery bypass graft (CABG). Patients were required to have a preindex diagnosis of at least one of the following: peripheral arterial disease, abdominal aortic aneurysm, carotid artery disease, or diabetes. A subset analysis was conducted with patients with data linkable to the Social Security Administration Master Death File. Direct medical costs were reported for each quarter following a CV event, for up to 36 months after the first CV event.

RESULTS

In total, 38,609 CHD-RE patients were included, mean age 57 years, 31% female. CABG, myocardial infarction, and percutaneous coronary intervention were the most frequent and most expensive first CV events, accounting for >75% of all first CV events with mean first quarter costs ranging from $17,454 (nonfatal transient ischemic attack) to $125,690 (fatal CABG). Overall, 15% of those with a first CV event went on to have a second event during the 36-month study period with mean first quarter nonfatal and fatal costs similar to first event levels. Third CV events were rare, happening in less than 3% of patients.

CONCLUSION

CV events among CHD-RE patients were costly regardless of sequence, averaging $47,433 in the first 90 days following an event and remaining high, never returning to preevent levels. When fatal, first CV event costs were 1.2 to 2.9 times higher than when nonfatal.

Update on the role of angiotensin in the pathophysiology of coronary atherothrombosis

BACKGROUND

Coronary atherothrombosis due to atherosclerotic plaque rupture or erosion is frequently associated with acute coronary syndromes (ACS). Significant efforts have been made to elucidate the pathophysiological mechanisms underlying acute coronary events.

MATERIALS AND METHODS

This narrative review is based on the material searched for and obtained via PubMed up to August 2014. The search terms we used were as follows: 'angiotensin, acute coronary syndromes, acute myocardial infarction' in combination with 'atherosclerosis, vulnerability, clinical trial, ACE inhibitors, inflammation'.

RESULTS

Among several regulatory components, the renin-angiotensin system (RAS) was shown as a key pathway modulating coronary atherosclerotic plaque vulnerability. Indeed, these molecules are involved in all stages of atherogenesis. Classically, the RAS is composed by a series of enzymatic reactions leading to the angiotensin (Ang) II generation and activity. However, the knowledge of RAS has expanded and become more complex. The discovery of novel components and their functions has revealed additional pathways that contribute to or counterbalance the actions of Ang II. In this review, we discussed on recent findings concerning the role of different angiotensin peptides in the pathophysiology of ACS and coronary atherothrombosis, exploring the link between these molecules and atherosclerotic plaque vulnerability.

CONCLUSIONS

Treatments selectively targeting angiotensins (including Mas and AT2 agonists, ACE2 recombinant, or Ang-(1-7) and almandine in oral formulations) have been tested in animal studies or in small human subgroups, expanding the perspective in the ACS prevention. These novel strategies, especially in the counter-regulatory axis ACE2/Ang-(1-7)/Mas, might be promising to reduce plaque vulnerability and inflammation.

Instrumental variable methods to assess quality of care the marginal effects of process-of-care on blood pressure change and treatment costs

BACKGROUND

Hypertension is poorly controlled. Team-based care and changes in the process of care have been proposed to address these quality problems. However, assessing care processes is difficult because they are often confounded even in randomized behavioral studies by unmeasured confounders based on discretion of health care providers.

OBJECTIVE

To evaluate the effects of process measures including number of counseling sessions about lifestyle modification and number of antihypertensive medications on blood pressure change and payer-perspective treatment costs.

METHODS

Data were obtained from two prospective, cluster randomized controlled clinical trials (Trial A and B) implementing physician-pharmacist collaborative interventions compared with usual care over six months in community-based medical offices in the Midwest. Multivariate linear regression models with both instrumental variable methods and as-treated methods were utilized. Instruments were indicators for trial and study arms. Models of blood pressure change and costs included both process measures, demographic variables, and clinical variables.

RESULTS

The analysis included 496 subjects. As-treated methods showed no significant associations between process and outcomes. The instruments used in the study were insufficient to simultaneously identify distinct process effects. However, the post-hoc instrumental variable models including one process measure at a time while controlling for the other process demonstrated significant associations between the processes and outcomes with estimates considerably larger than as-treated estimates.

CONCLUSIONS

Instrumental variable methods with combined randomized behavioral studies may be useful to evaluate the effects of different care processes. However, substantial distinct process variation across studies is needed to fully capitalize on this approach. Instrumental variable methods focusing on individual processes provided larger and stronger outcome relationships than those found using as-treated methods which are subject to confounding.

Indirect and direct costs of acute coronary syndromes with comorbid atrial fibrillation, heart failure, or both

BACKGROUND

The objective of this study was to determine the direct and indirect costs of acute coronary syndromes (ACS) alone and with common cardiovascular comorbidities.

METHODS

A retrospective analysis was conducted using the Medical Expenditure Panel Survey from 1998 to 2009. Four mutually exclusive cohorts were evaluated: ACS only, ACS with atrial fibrillation (AF), ACS with heart failure (HF), and ACS with both conditions. Direct costs were calculated for all-cause and cardiovascular-related health care resource utilization. Indirect costs were determined from productivity losses from missed days of work. Regression analysis was developed for each outcome controlling for age, US census region, insurance coverage, sex, race, ethnicity, education attainment, family income, and comorbidity burden. A negative binomial regression model was used for health care utilization variables. A Tobit model was utilized for health care costs and productivity loss variables.

RESULTS

Total health care costs were greatest for those with ACS and both AF and HF ($38,484±5,191) followed by ACS with HF ($32,871±2,853), ACS with AF ($25,192±2,253), and ACS only ($17,954±563). Compared with the ACS only cohort, the mean all-cause adjusted health care costs associated with ACS with AF, ACS with HF, and ACS with AF and HF were $5,073 (95% confidence interval [CI] 719-9,427), $11,297 (95% CI 5,610-16,985), and $15,761 (95% CI 4,784-26,738) higher, respectively. Average wage losses associated with ACS with and without AF and/or HF amounted to $5,266 (95% CI -7,765, -2,767), when compared with patients without these conditions.

CONCLUSION

ACS imposes a significant economic burden at both the individual and society level, particularly when with comorbid AF and HF.