Faculty Bibliography

BACKGROUND: Cardiac stress testing, particularly with imaging, has been the focus of debates about rising health care costs, inappropriate use, and patient safety in the context of radiation exposure. OBJECTIVE: To determine whether U.S. trends in cardiac stress test use may be attributable to population shifts in demographics, risk factors, and provider characteristics and evaluate whether racial/ethnic disparities exist in physician decision making. DESIGN: Analyses of repeated cross-sectional data. SETTING: National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey (1993 to 2010). PATIENTS: Adults without coronary heart disease. MEASUREMENTS: Cardiac stress test referrals and inappropriate use. RESULTS: Between 1993 to 1995 and 2008 to 2010, the annual number of U.S. ambulatory visits in which a cardiac stress test was ordered or performed increased from 28 per 10,000 visits to 45 per 10,000 visits. No trend was found toward more frequent testing after adjustment for patient characteristics, risk factors, and provider characteristics (P = 0.134). Cardiac stress tests with imaging comprised a growing portion of all tests, increasing from 59% in 1993 to 1995 to 87% in 2008 to 2010. At least 34.6% were probably inappropriate, with associated annual costs and harms of $501 million and 491 future cases of cancer. Authors found no evidence of a lower likelihood of black patients receiving a cardiac stress test (odds ratio, 0.91 [95% CI, 0.69 to 1.21]) than white patients, although some evidence of disparity in Hispanic patients was found (odds ratio, 0.75 [CI, 0.55 to 1.02]). LIMITATION: Cross-sectional design with limited clinical data. CONCLUSION: National growth in cardiac stress test use can largely be explained by population and provider characteristics, but use of imaging cannot. Physician decision making about cardiac stress test use does not seem to contribute to racial/ethnic disparities in cardiovascular disease. PRIMARY FUNDING SOURCE: National Heart, Lung, and Blood Institute and the National Center for Advancing Translational Sciences.

OBJECTIVE: The purpose of this study was to evaluate the association of physician continuity of care with length of stay, likelihood of weekend discharge, in-hospital mortality and 30-day readmission. DESIGN: A cohort study of hospitalized medical patients. The primary exposure was the weekend usual provider continuity (UPC) over the initial weekend of care. This metric was adapted from an outpatient continuity of care index. Regression models were developed to determine the association between UPC and outcomes. SETTING: An academic medical center. MAIN OUTCOME MEASURE: Length of stay which was calculated as the number of days from the first Saturday of the hospitalization to the day of discharge. RESULTS: Of the 3391 patients included in this study, the prevalence of low, moderate and high UPC for the initial weekend of hospitalization was 58.7, 22.3 and 19.1%, respectively. When compared with low continuity of care, both moderate and high continuity of care were associated with reduced length of stay, with adjusted rate ratios of 0.92 (95% CI 0.86-1.00) and 0.64 (95% CI 0.53-0.76), respectively. High continuity of care was associated with likelihood of weekend discharge (adjusted odds ratio 2.84, 95% CI 2.11-3.83) but was not significantly associated with mortality (adjusted odds ratio 0.72, 95% CI 0.29-1.80) or readmission (adjusted odds ratio 0.88, 95% CI 0.68-1.14) when compared with low continuity of care. CONCLUSIONS: Increased weekend continuity of care is associated with reduced length of stay. Improvement in weekend cross-coverage and patient handoffs may be useful to improve clinical outcomes.

Background: Appropriate use criteria (AUC) for imaging stress testing address concerns about utilization growth, high costs, and radiation safety. However, differences in test use over time between primary care physicians (PCPs) and cardiologists have not been examined. Methods: We analyzed 164,569 ambulatory visits from the National Ambulatory Medical Care Survey from 1993-2010. Patients with CAD were excluded. The main outcome was survey-weighted incidence of referrals for imaging stress. Referrals were considered inappropriate in patients with neither ischemic equivalents (chest pain, anginal equivalent, or ischemic ECG abnormalities) nor CAD risk equivalents. Logistic regressions examined time trends and adjusted for clinical characteristics. Results: Ambulatory visits resulting in an inappropriate imaging stress referral increased from 523,000 in 1993-1995 to 1.63 million in 2008- 2010. PCP referral increased until 2008-2010 when referrals fell; P=0.33 for time trend. However, among cardiologists, inappropriate testing rates rose during each period, including 2008-2010 when AUC were well accepted, rising from 260 to 710 per 10,000 visits (P<0.01). The portion of inappropriate tests was stable over time: 50% for cardiologists; 55-65% for PCPs. Conclusion: Growth in inappropriate imaging stress tests is driven on the margin by cardiologists, and PCPs have reduced utilization in recent years. Payers and policy makers designing quality metrics should consider these patterns

BACKGROUND: Reduced low forced expiratory volume in 1 second (FEV1) is reportedly associated with an increased risk of atrial fibrillation (AF). Extant reports do not provide separate estimates for never smokers or for blacks, who incongruously have lower AF incidence than whites. METHODS AND RESULTS: We examined 15 004 middle-aged blacks and whites enrolled in the Atherosclerosis Risk in Communities (ARIC) cohort study. Standardized spirometry data were collected at the baseline examination. Incident AF was identified from the first among the following: International Classification of Diseases codes for AF on hospital discharge records or death certificates or 12-lead ECGs performed during 3 triennial follow-up visits. Over an average follow-up of 17.5 years, a total of 1691 participants (11%) developed new-onset AF. The rate of incident AF was inversely associated with FEV1 in each of the 4 race and sex groups. After multivariable adjustment for traditional cardiovascular disease risk factors and height, hazard ratios of AF comparing the lowest with the highest quartile of FEV1 were 1.37 (95% confidence interval, 1.02-1.83) for white women, 1.49 (95% confidence interval, 1.16-1.91) for white men, 1.63 (95% confidence interval, 1.00-2.66) for black women, and 2.36 (95% confidence interval, 1.30-4.29) for black men. The above associations were observed across all smoking status categories. Moderate/severe airflow obstruction (FEV1/forced vital capacity <0.70 and FEV1 < 80% of predicted value) was also associated with higher AF incidence. CONCLUSIONS: In this large population-based study with a long-term follow-up, reduced FEV1 and obstructive respiratory disease were associated with a higher AF incidence after adjustment for measured confounders.

BACKGROUND: Previous studies have suggested that weekend hospital care is inferior to weekday care and that this difference may be related to diminished care intensity. The purpose of this study was to determine whether a metric for measuring intensity of hospital care based on utilization of the electronic health record (EHR) was associated with patient-level outcomes. METHODS: We performed a cohort study of hospitalizations at an academic medical center. Intensity of care was defined as the hourly number of provider accessions of the electronic health record, termed "EHR interactions." Hospitalizations were categorized based on the mean difference in EHR interactions between the first Friday and Saturday of hospitalization. We used regression models to determine the association of these categories with patient outcomes after adjusting for covariates. RESULTS: EHR interactions decreased from Friday to Saturday in 77% of the 9,051 hospitalizations included in the study. As compared to hospitalizations with no change in Friday to Saturday EHR interactions, the relative lengths of stay for hospitalizations with a small, moderate, and large decrease in EHR interactions were 1.05 (95% CI 1.00-1.10), 1.11 (95% CI 1.05-1.17), and 1.25 (95% CI 1.15-1.35), respectively. Although a large decrease in EHR interactions was associated with in-hospital mortality, these findings were not significant after risk adjustment (odds ratio 1.74, 95% CI 0.93-3.25). CONCLUSIONS: Intensity of inpatient care, measured by EHR interactions, significantly diminished from Friday to Saturday, and this decrease was associated with length of stay. Hospitals should consider monitoring and correcting temporal fluctuations in care intensity.

OBJECTIVES: The study sought to assess the quality of care for heart failure patients who are hospitalized for all causes. BACKGROUND: Performance measures for heart failure target patients with a principal diagnosis of heart failure. However, patients with heart failure are commonly hospitalized for other causes and may benefit from treatments such as angiotensin-converting enzyme (ACE) inhibitors for left ventricular (LV) systolic dysfunction. METHODS: We assessed rates of compliance with care measures for patients hospitalized with acute or chronic heart failure in the ARIC (Atherosclerosis Risk In Communities) study surveillance catchment area from 2005 to 2009. Rates of compliance were compared between patients with a principal discharge diagnosis of heart failure and those with another principal discharge diagnosis. RESULTS: Of 4,345 hospitalizations of heart failure patients, 39.6% carried a principal diagnosis of heart failure. Patients with a principal heart failure diagnosis had higher rates of LV function assessment (89.1% vs. 82.5%; adjusted prevalence ratio [aPR]: 1.07; 95% confidence interval [CI]: 1.04 to 1.10) and discharge ACE inhibitor/angiotensin receptor blocker (ARB) in LV dysfunction (64.1% vs. 56.3%; aPR: 1.11; 95% CI: 1.03 to 1.20) as compared to patients hospitalized for another cause. LV assessment and ACE inhibitor/ARB use were associated with reductions in 1-year post-discharge mortality (adjusted odds ratio: 0.66, 95% CI: 0.51 to 0.85; adjusted odds ratio: 0.72, 95% CI: 0.54 to 0.96, respectively) that did not differ for patients with versus without a principal heart failure diagnosis. CONCLUSIONS: Compared with individuals hospitalized with a principal diagnosis of heart failure, heart failure patients hospitalized for other causes were less likely to receive guideline recommended care. Quality initiatives may improve care by targeting hospitalizations with either principal or secondary heart failure diagnoses.

BACKGROUND: Exercise testing with echocardiography or myocardial perfusion imaging is widely used to risk-stratify patients with suspected coronary artery disease. However, reports of diagnostic performance rarely adjust for referral bias, and this practice may adversely influence patient care. Therefore, we evaluated the potential impact of referral bias on diagnostic effectiveness and clinical decision-making. METHODS AND RESULTS: Searching PubMed and EMBASE (1990-2012), 2 investigators independently evaluated eligibility and abstracted data on study characteristics and referral patterns. Diagnostic performance reported in 4 previously published meta-analyses of exercise echocardiography and myocardial perfusion imaging was adjusted using pooled referral rates and Bayesian methods. Twenty-one studies reported referral patterns in 49 006 patients (mean age 60.7 years, 39.6% women, and 0.8% prior history of myocardial infarction). Catheterization referral rates after normal and abnormal exercise tests were 4.0% (95% CI, 2.9% to 5.0%) and 42.5% (36.2% to 48.9%), respectively, with odds ratio for referral after an abnormal test of 14.6 (10.7 to 19.9). After adjustment for referral, exercise echocardiography sensitivity fell from 84% (80% to 89%) to 34% (27% to 41%), and specificity rose from 77% (69% to 86%) to 99% (99% to 100%). Similarly, exercise myocardial perfusion imaging sensitivity fell from 85% (81% to 88%) to 38% (31% to 44%), and specificity rose from 69% (61% to 78%) to 99% (99% to 100%). Summary receiver operating curve analysis demonstrated only modest changes in overall discriminatory power but adjusting for referral increased positive-predictive value and reduced negative-predictive value. CONCLUSIONS: Exercise echocardiography and myocardial perfusion imaging are considerably less sensitive and more specific for coronary artery disease after adjustment for referral. Given these findings, future work should assess the comparative ability of these and other tests to rule-in versus rule-out coronary artery disease.