Bradley G. Hammill

Relationship Between Early Physician Follow-up and 30-Day Readmission Among Medicare Beneficiaries Hospitalized for Heart Failure

CONTEXT Readmission after hospitalization for heart failure is common. Early outpatient follow-up after hospitalization has been proposed as a means of reducing readmission rates. However, there are limited data describing patterns of follow-up after heart failure hospitalization and its association with readmission rates. OBJECTIVE To examine associations between outpatient follow-up within 7 days after discharge from a heart failure hospitalization and readmission within 30 days. DESIGN, SETTING, AND PATIENTS Observational analysis of patients 65 years or older with heart failure and discharged to home from hospitals participating in the Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients With Heart Failure and the Get With the Guidelines-Heart Failure quality improvement program from January 1, 2003, through December 31, 2006. MAIN OUTCOME MEASURE All-cause readmission within 30 days after discharge. RESULTS The study population included 30,136 patients from 225 hospitals. Median length of stay was 4 days (interquartile range, 2-6) and 21.3% of patients were readmitted within 30 days. At the hospital level, the median percentage of patients who had early follow-up after discharge from the index hospitalization was 38.3% (interquartile range, 32.4%-44.5%). Compared with patients whose index admission was in a hospital in the lowest quartile of early follow-up (30-day readmission rate, 23.3%), the rates of 30-day readmission were 20.5% among patients in the second quartile (risk-adjusted hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.78-0.93), 20.5% among patients in the third quartile (risk-adjusted HR, 0.87; 95% CI, 0.78-0.96), and 20.9% among patients in the fourth quartile (risk-adjusted HR, 0.91; 95% CI, 0.83-1.00). CONCLUSIONS Among patients who are hospitalized for heart failure, substantial variation exists in hospital-level rates of early outpatient follow-up after discharge. Patients who are discharged from hospitals that have higher early follow-up rates have a lower risk of 30-day readmission. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00344513.

Validation of European System for Cardiac Operative Risk Evaluation (EuroSCORE) in North American cardiac surgery

OBJECTIVE To assess the performance of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) when applied in a North American cardiac surgical population. METHODS The simple additive EuroSCORE model was applied to predict operative mortality (in-hospital or 30-day) in 401684 patients undergoing coronary or valve surgery in 1998 and 1999 as well as in 188913 patients undergoing surgery in 1995 in the Society of Thoracic Surgeons (STS) database. RESULTS The proportion of isolated coronary artery bypass grafting (CABG) was greater in STS patients (84%) than in Europe (65%). STS patients were also older (mean age 65.3 versus 62.5), and had more diabetes (30 versus 17%) and prior cardiac surgery (11 versus 7%). Other comorbidity was also significantly more prevalent in STS patients. EuroSCORE predicted overall mortality was virtually identical to the observed mortality (1998/1999: predicted 3.994%, observed 3.992%; 1995: observed and predicted 4.156%). Predicted mortality also closely matched observed mortality across the risk groups. Discrimination was good to very good for the population overall and for isolated CABG in both time periods, with the area under the receiver operating characteristic curve between 0.75 and 0.78. CONCLUSION Despite substantial demographic differences between Europe and North America, EuroSCORE performs very well in the STS database, and can be recommended as a simple, additive risk stratification system on both sides of the Atlantic.

Long-Term Adherence to Evidence-Based Secondary Prevention Therapies in Coronary Artery Disease

Background— Studies have examined the use of evidence-based therapies for coronary artery disease (CAD) in the short term and at hospital discharge, but few have evaluated long-term use. Methods and Results— Using the Duke Databank for Cardiovascular Disease for the years 1995 to 2002, we determined the annual prevalence and consistency of self-reported use of aspirin, &bgr;-blockers, lipid-lowering agents, and their combinations in all CAD patients and of angiotensin-converting enzyme inhibitors (ACEIs) in those with and without heart failure. Logistic-regression models identified characteristics associated with consistent use (reported on ≥2 consecutive follow-up surveys and then through death, withdrawal, or study end), and Cox proportional-hazards models explored the association of consistent use with mortality. Use of all agents and combinations thereof increased yearly. In 2002, 83% reported aspirin use; 61%, &bgr;-blocker use; 63%, lipid-lowering therapy use; 54%, aspirin and &bgr;-blocker use; and 39%, use of all 3. Consistent use was as follows: For aspirin, 71%; &bgr;-blockers, 46%; lipid-lowering therapy, 44%; aspirin and &bgr;-blockers, 36%; and all 3, 21%. Among patients without heart failure, 39% reported ACEI use in 2002; consistent use was 20%. Among heart failure patients, ACEI use was 51% in 2002 and consistent use, 39%. Except for ACEIs among patients without heart failure, consistent use was associated with lower adjusted mortality: Aspirin hazard ratio (HR), 0.58 and 95% confidence interval (CI), 0.54 to 0.62; &bgr;-blockers, HR, 0.63 and 95% CI, 0.59 to 0.67; lipid-lowering therapy, HR, 0.52 and 95% CI, 0.42 to 0.65; all 3, HR, 0.67 and 95% CI, 0.59 to 0.77; aspirin and &bgr;-blockers, HR, 0.61 and 95% CI, 0.57 to 0.65; and ACEIs among heart failure patients, HR, 0.75 and 95% CI, 0.67 to 0.84. Conclusions— Use of evidence-based therapies for CAD has improved but remains suboptimal. Although improved discharge prescription of these agents is needed, considerable attention must also be focused on understanding and improving long-term adherence.

Relationship Between Cardiac Rehabilitation and Long-Term Risks of Death and Myocardial Infarction Among Elderly Medicare Beneficiaries

Background— For patients with coronary heart disease, exercise-based cardiac rehabilitation improves survival rate and has beneficial effects on risk factors for coronary artery disease. The relationship between the number of sessions attended and long-term outcomes is unknown. Methods and Results— In a national 5% sample of Medicare beneficiaries, we identified 30 161 elderly patients who attended at least 1 cardiac rehabilitation session between January 1, 2000, and December 31, 2005. We used a Cox proportional hazards model to estimate the relationship between the number of sessions attended and death and myocardial infarction (MI) at 4 years. The cumulative number of sessions was a time-dependent covariate. After adjustment for demographic characteristics, comorbid conditions, and subsequent hospitalization, patients who attended 36 sessions had a 14% lower risk of death (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.77 to 0.97) and a 12% lower risk of MI (HR, 0.88; 95% CI, 0.83 to 0.93) than those who attended 24 sessions; a 22% lower risk of death (HR, 0.78; 95% CI, 0.71 to 0.87) and a 23% lower risk of MI (HR, 0.77; 95% CI, 0.69 to 0.87) than those who attended 12 sessions; and a 47% lower risk of death (HR, 0.53; 95% CI, 0.48 to 0.59) and a 31% lower risk of MI (HR, 0.69; 95% CI, 0.58 to 0.81) than those who attended 1 session. Conclusions— Among Medicare beneficiaries, a strong dose–response relationship existed between the number of cardiac rehabilitation sessions and long-term outcomes. Attending all 36 sessions reimbursed by Medicare was associated with lower risks of death and MI at 4 years compared with attending fewer sessions.

Using Inverse Probability-Weighted Estimators in Comparative Effectiveness Analyses With Observational Databases

Inverse probability-weighted estimation is a powerful tool for use with observational data. In this article, we describe how this propensity score-based method can be used to compare the effectiveness of 2 or more treatments. First, we discuss the inherent problems in using observational data to assess comparative effectiveness. Next, we provide a conceptual explanation of inverse probability-weighted estimation and point readers to sources that address the method in more formal, technical terms. Finally, we offer detailed guidance about how to implement the estimators in comparative effectiveness analyses.

Linking Inpatient Clinical Registry Data to Medicare Claims Data Using Indirect Identifiers

BACKGROUND Inpatient clinical registries generally have limited ability to provide a longitudinal perspective on care beyond the acute episode. We present a method to link hospitalization records from registries with Medicare inpatient claims data, without using direct identifiers, to create a unique data source that pairs rich clinical data with long-term outcome data. METHODS AND RESULTS The method takes advantage of the hospital clustering observed in each database by demonstrating that different combinations of indirect identifiers within hospitals yield a large proportion of unique patient records. This high level of uniqueness also allows linking without advance knowledge of the Medicare provider number of each registry hospital. We applied this method to 2 inpatient databases and were able to identify 81% of 39,178 records in a large clinical registry of patients with heart failure and 91% of 6,581 heart failure records from a hospital inpatient database. The quality of the link is high, and reasons for incomplete linkage are explored. Finally, we discuss the unique opportunities afforded by combining claims and clinical data for specific analyses. CONCLUSIONS In the absence of direct identifiers, it is possible to create a high-quality link between inpatient clinical registry data and Medicare claims data. The method will allow researchers to use existing data to create a linked claims-clinical database that capitalizes on the strengths of both types of data sources.

Incidence and Prevalence of Atrial Fibrillation and Associated Mortality Among Medicare Beneficiaries, 1993–2007

Background— Atrial fibrillation (AF) is a common and costly problem among older persons. The frequency of AF increases with age, but representative national data about incidence and prevalence are limited. We examined the annual incidence, prevalence, and mortality associated with AF among older persons. Methods and Results— In a retrospective cohort study of Medicare beneficiaries 65 years and older diagnosed with AF between 1993 and 2007, we measured annual age- and sex-adjusted incidence and prevalence of AF and mortality following an AF diagnosis. Among 433 123 patients with incident AF, the mean age was 80 years, 55% were women, and 92% were white. The incidence of AF remained steady during the 14-year study period, ranging from 27.3 to 28.3 per 1000 person-years. Incidence rates were consistently higher among men and white beneficiaries. The prevalence of AF increased across the study period (mean, 5% per year) and was robust to sensitivity analyses. Among beneficiaries with incident AF in 2007, 36% had heart failure, 84% had hypertension, 30% had cerebrovascular disease, and 8% had dementia. Mortality after AF diagnosis declined slightly over time but remained high. In 2007, the age- and sex-adjusted mortality rates were 11% at 30 days and 25% at 1 year. Conclusions— Among older Medicare beneficiaries, incident AF is common and has remained relatively stable for more than a decade. Incident AF is associated with significant comorbidity and mortality; death occurs in one-quarter of beneficiaries within 1 year.

Incidence and Prevalence of Heart Failure in Elderly Persons, 1994-2003

BACKGROUND Recent analyses have presented conflicting evidence regarding the incidence and prevalence of heart failure in the United States. We sought to estimate the annual incidence and prevalence of heart failure and associated survival in elderly persons from January 1, 1994, through December 31, 2003. METHODS We conducted a retrospective cohort study of 622,789 Medicare beneficiaries 65 years or older who were diagnosed as having heart failure between 1994 and 2003. The main outcome measures were incidence and prevalence of heart failure and survival following a heart failure diagnosis. RESULTS The incidence of heart failure declined from 32 per 1000 person-years in 1994 to 29 per 1000 person-years in 2003 (P < .01). Incidence declined most sharply among beneficiaries aged 80 to 84 years (from 57.5 to 48.4 per 1000 person-years, P < .01) and increased slightly among beneficiaries aged 65 to 69 years (from 17.5 to 19.3 per 1000 person-years, P < .01). Although risk-adjusted mortality declined slightly from 1994 to 2003, the prognosis for patients diagnosed as having heart failure remains poor. In 2002, risk-adjusted 1-year mortality was 27.5%, more than 3 times higher than for age- and sex-matched patients. CONCLUSIONS Although the incidence of heart failure has declined somewhat during the past decade, modest survival gains have resulted in an increase in the number of patients living with heart failure. Identifying optimal strategies for the treatment and management of heart failure will become increasingly important as the size of the Medicare population grows.

Clinical Effectiveness of Beta-Blockers in Heart Failure : Findings From the OPTIMIZE-HF (Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients With Heart Failure) Registry

OBJECTIVES We sought to examine associations between initiation of beta-blocker therapy and outcomes among elderly patients hospitalized for heart failure. BACKGROUND Beta-blockers are guideline-recommended therapy for heart failure, but their clinical effectiveness is not well understood, especially in elderly patients. METHODS We merged Medicare claims data with OPTIMIZE-HF (Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients With Heart Failure) records to examine long-term outcomes of eligible patients newly initiated on beta-blocker therapy. We used inverse probability-weighted Cox proportional hazards models to determine the relationships among treatment and mortality, rehospitalization, and a combined mortality-rehospitalization end point. RESULTS Observed 1-year mortality was 33%, and all-cause rehospitalization was 64%. Among 7,154 patients hospitalized with heart failure and eligible for beta-blockers, 3,421 (49%) were newly initiated on beta-blocker therapy. Among patients with left ventricular systolic dysfunction (LVSD) (n = 3,001), beta-blockers were associated with adjusted hazard ratios of 0.77 (95% confidence interval [CI]: 0.68 to 0.87) for mortality, 0.89 (95% CI: 0.80 to 0.99) for rehospitalization, and 0.87 (95% CI: 0.79 to 0.96) for mortality-rehospitalization. Among patients with preserved systolic function (n = 4,153), beta-blockers were associated with adjusted hazard ratios of 0.94 (95% CI: 0.84 to 1.07) for mortality, 0.98 (95% CI: 0.90 to 1.06) for rehospitalization, and 0.98 (95% CI: 0.91 to 1.06) for mortality-rehospitalization. CONCLUSIONS In elderly patients hospitalized with heart failure and LVSD, incident beta-blocker use was clinically effective and independently associated with lower risks of death and rehospitalization. Patients with preserved systolic function had poor outcomes, and beta-blockers did not significantly influence the mortality and rehospitalization risks for these patients.

Changes in the Use and Costs of Diagnostic Imaging Among Medicare Beneficiaries With Cancer, 1999-2006

CONTEXT Emerging technologies, changing diagnostic and treatment patterns, and changes in Medicare reimbursement are contributing to increasing use of imaging in cancer. Imaging is the fastest growing expense for Medicare but has not been examined among beneficiaries with cancer. OBJECTIVE To examine changes in the use of imaging and how those changes contribute to the overall cost of cancer care. DESIGN, SETTING, AND PATIENTS Analysis of a nationally representative 5% sample of claims from the US Centers for Medicare & Medicaid Services from 1999 through 2008. Patients were Medicare beneficiaries with incident breast cancer, colorectal cancer, leukemia, lung cancer, non-Hodgkin lymphoma, or prostate cancer. MAIN OUTCOME MEASURES Use and cost of imaging by modality, year, and cancer type. RESULTS There were 100,954 incident cases of breast cancer, colorectal cancer, leukemia, lung cancer, non-Hodgkin lymphoma, and prostate cancer from 1999 through 2006. Significant mean annual increases in imaging use occurred among all cancer types for positron emission tomography (35.9%-53.6%), bone density studies (6.3%-20.0%), echocardiograms (5.0%-7.8%), magnetic resonance imaging (4.4%-11.5%), and ultrasound (0.7%-7.4%). Conventional radiograph rates decreased or stayed the same. As of 2006, beneficiaries with lung cancer and beneficiaries with lymphoma incurred the largest overall imaging costs, exceeding a mean of