F.L. Lucas

Temporal Trends in the Utilization of Diagnostic Testing and Treatments for Cardiovascular Disease in the United States, 1993–2001

Background— Rates of invasive testing and treatment for coronary artery disease have increased over time. Less is known about trends in the utilization of noninvasive cardiac testing for coronary artery disease. The objective of this study was 2-fold: to explore temporal trends in the utilization of noninvasive and invasive cardiac services in relation to changes in the prevalence of cardiac disease, and to examine whether temporal increases have been targeted to potentially underserved populations. Methods and Results— We performed an annual cross-sectional population-based study of Medicare patients from 1993 to 2001. We identified stress testing, cardiac catheterization, and revascularization procedures, as well as hospitalizations for acute myocardial infarction, during each year and calculated population-based rates for each using the total fee-for-service Medicare population as the denominator and adjusting for age, gender, and race. We observed marked growth in the utilization rates of cardiac services over time, with relative rates nearly doubling for most services. Acute myocardial infarction hospitalization rates have remained stable over the study period. Although rates of all procedures except coronary artery bypass increased in all subgroups, differences in rates of cardiac testing and treatment between nonblack men and other subgroups persisted over time. Conclusions— Temporal increases in the use of noninvasive and invasive cardiac services are not explained by changes in disease prevalence and have not succeeded in narrowing preexisting treatment differences by gender and race. Such increases, although conferring benefit for some, may expose others to risk and cost without benefit.

Frequency of Stress Testing to Document Ischemia Prior to Elective Percutaneous Coronary Intervention

CONTEXT Guidelines call for documenting ischemia in patients with stable coronary artery disease prior to elective percutaneous coronary intervention (PCI). OBJECTIVE To determine the frequency and predictors of stress testing prior to elective PCI in a Medicare population. DESIGN, SETTING, AND PATIENTS Retrospective, observational cohort study using claims data from a 20% random sample of 2004 Medicare fee-for-service beneficiaries aged 65 years or older who had an elective PCI (N = 23 887). MAIN OUTCOME MEASURES Percentage of patients who underwent stress testing within 90 days prior to elective PCI; variation in stress testing prior to PCI across 306 hospital referral regions; patient, physician, and hospital characteristics that predicted the appropriate use of stress testing prior to elective PCI. RESULTS In the United States, 44.5% (n = 10 629) of patients underwent stress testing within the 90 days prior to elective PCI. There was wide regional variation among the hospital referral regions with stress test rates ranging from 22.1% to 70.6% (national mean, 44.5%; interquartile range, 39.0%-50.9%). Female sex (adjusted odds ratio [AOR], 0.91; 95% confidence interval [CI], 0.86-0.97), age of 85 years or older (AOR, 0.83; 95% CI, 0.72-0.95), a history of congestive heart failure (AOR, 0.85; 95% CI, 0.79-0.92), and prior cardiac catheterization (AOR, 0.45; 95% CI, 0.38-0.54) were associated with a decreased likelihood of prior stress testing. A history of chest pain (AOR, 1.28; 95% CI, 1.09-1.54) and black race (AOR, 1.26; 95% CI, 1.09-1.46) increased the likelihood of stress testing prior to PCI. Patients treated by physicians performing 150 or more PCIs per year were less likely to have stress testing prior to PCI (AOR, 0.84; 95% CI, 0.77-0.93). No hospital characteristics were associated with receipt of stress testing. CONCLUSION The majority of Medicare patients with stable coronary artery disease do not have documentation of ischemia by noninvasive testing prior to elective PCI.

Surgeon Specialty and Operative Mortality With Lung Resection

Objective:We sought to examine the effect of subspecialty training on operative mortality following lung resection. Summary Background Data:While several different surgical subspecialists perform lung resection for cancer, many believe that this procedure is best performed by board-certified thoracic surgeons. Methods:Using the national Medicare database 1998 to 1999, we identified patients undergoing lung resection (lobectomy or pneumonectomy) for lung cancer. Operating surgeons were identified by unique physician identifier codes contained in the discharge abstract. We used the American Board of Thoracic Surgery database, as well as physician practice patterns, to designate surgeons as general surgeons, cardiothoracic surgeons, or noncardiac thoracic surgeons. Using logistic regression models, we compared operative mortality across surgeon subspecialties, adjusting for patient, surgeon, and hospital characteristics. Results:Overall, 25,545 Medicare patients underwent lung resection, 36% by general surgeons, 39% by cardiothoracic surgeons, and 25% by noncardiac thoracic surgeons. Patient characteristics did not differ substantially by surgeon specialty. Adjusted operative mortality rates were lowest for cardiothoracic and noncardiac thoracic surgeons (7.6% general surgeons, 5.6% cardiothoracic surgeons, 5.8% noncardiac thoracic surgeons, P = 0.001). In analyses restricted to high-volume surgeons (>20 lung resections/y), mortality rates were lowest for noncardiac thoracic surgeons (5.1% noncardiac thoracic, 5.2% cardiothoracic, and 6.1% general surgeons) (P < 0.01 for difference between general surgeons and thoracic surgeons). In analyses restricted to high-volume hospitals (>45 lung resections/y), mortality rates were again lowest for noncardiac thoracic surgeons (5.0% noncardiac thoracic, 5.3% cardiothoracic, and 6.1% general surgeons) (P < 0.01 for differences between all 3 groups). Conclusions:Operative mortality with lung resection varies by surgeon specialty. Some, but not all, of this variation in operative mortality is attributable to hospital and surgeon volume.

Operator Volume and Outcomes in 12,988 Percutaneous Coronary Interventions

OBJECTIVES We sought to determine whether there is a relation between operator volume and outcomes for percutaneous coronary interventions (PCIs). BACKGROUND A 1993 American College of Cardiology/American Heart Association task force stated that cardiologists should perform > or = 75 procedures/year to maintain competency in PCIs; however, there were limited data available to support this statement. METHODS Data were collected from 1990 through 1993 on 12,988 PCIs (12,118 consecutive hospital admissions) performed by 31 cardiologists at two hospitals in New Hampshire and two in Maine and one hospital in Massachusetts supporting these procedures. Operators were categorized into terciles based on annualized volume of procedures. Univariate and multivariate regression analyses were used to control for case-mix. Successful outcomes included angiographic success (all lesions attempted dilated to < 50% residual stenosis) and clinical success (at least one lesion dilated to < 50% residual stenosis and no adverse outcomes). In-hospital adverse outcomes included coronary artery bypass graft surgery (CABG), myocardial infarction (MI) and death. RESULTS After adjustment for case-mix, higher angiographic (low, middle and high terciles: 84.7%, 86.1% and 90.3%, p-trend 0.006) and clinical success rates (85.8%, 88.0% and 90.7%, p-trend 0.025), with fewer referrals to CABG (4.54%, 3.75% and 2.49%, p-trend <0.001), were seen as operator volume increased. There was a trend toward higher MI rates for high volume operators (2.00%, 1.98% and 2.57%, p-trend 0.06); all terciles had similar in-hospital mortality rates (1.09%, 0.96% and 1.05%, p-trend 0.8). CONCLUSIONS There is a significant relation between operator volume and outcomes in PCIs. Efforts should be directed toward understanding why high volume operators are more successful and encounter fewer adverse outcomes.Objectives. We sought to determine whether there is a relation between operator volume and outcomes for percutaneous coronary interventions (PCIs). Background. A 1993 American College of Cardiology/American Heart Association task force stated that cardiologists should perform ≥75 procedures/year to maintain competency in PCIs; however, there were limited data available to support this statement. Methods. Data were collected from 1990 through 1993 on 12,988 PCIs (12,118 consecutive hospital admissions) performed by 31 cardiologists at two hospitals in New Hampshire and two in Maine and one hospital in Massachusetts supporting these procedures. Operators were categorized into terciles based on annualized volume of procedures. Univariate and multivariate regression analyses were used to control for case-mix. Successful outcomes included angiographic success (all lesions attempted dilated to <50% residual stenosis) and clinical success (at least one lesion dilated to <50% residual stenosis and no adverse outcomes). In-hospital adverse outcomes included coronary artery bypass graft surgery (CABG), myocardial infarction (MI) and death. Results. After adjustment for case-mix, higher angiographic (low, middle and high terciles: 84.7%, 86.1% and 90.3%, p-trend 0.006) and clinical success rates (85.8%, 88.0% and 90.7%, p-trend 0.025), with fewer referrals to CABG (4.54%, 3.75% and 2.49%, p-trend <0.001), were seen as operator volume increased. There was a trend toward higher MI rates for high volume operators (2.00%, 1.98% and 2.57%, p-trend 0.06); all terciles had similar in-hospital mortality rates (1.09%, 0.96% and 1.05%, p-trend 0.8). Conclusions. There is a significant relation between operator volume and outcomes in PCIs. Efforts should be directed toward understanding why high volume operators are more successful and encounter fewer adverse outcomes.

Diagnostic-Therapeutic Cascade Revisited: Coronary Angiography, Coronary Artery Bypass Graft Surgery, and Percutaneous Coronary Intervention in the Modern Era

Background— There is wide geographic variation in the use of coronary revascularization in the United States. Rates are closely related to rates of coronary angiography. We assessed the relationship between coronary angiography and coronary artery revascularization by procedure type (coronary artery bypass graft surgery or percutaneous coronary intervention). Methods and Results— Using Part B claims for a 20% sample of the Medicare population, we calculated population-based rates of testing and treatment by region, using events identified in Part B claims as the numerator and the total number of Medicare beneficiaries residing in the area as the denominator and adjusting for regional differences in demographic characteristics with the indirect method. Cardiac catheterization rates varied substantially across regions, from 16 to 77 per 1000 Medicare beneficiaries. The relationship between coronary angiography rates and total coronary revascularization rates was strong (R2=0.84). However, there was only a modest association between coronary angiography rates and coronary artery bypass graft surgery rates (R2=0.41) with the suggestion of a threshold effect. The association between coronary angiography rates and percutaneous coronary intervention rates was strong (R2=0.78) and linear. Conclusions— The diagnostic-therapeutic cascade for coronary artery disease differs by therapeutic intervention. For coronary artery bypass graft surgery, the relationship is modest, and there appears to be a testing threshold beyond which additional tests do not result in additional surgeries. For percutaneous coronary intervention, the relationship is very tight, and no threshold appears to exist. Given the results of recent studies of medical versus invasive management of stable coronary disease, patients living in high-diagnostic-intensity regions may be getting more treatment than they want or need.Background There is wide geographic variation in the use of coronary revascularization in the United States. Rates are closely related to rates of coronary angiography. We assessed the relationship between coronary angiography and coronary artery revascularization by procedure type (coronary artery bypass graft surgery, CABG, or percutaneous coronary intervention, PCI).

Carotid endarterectomy after NASCET and ACAS: A statewide study

PURPOSE Since the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the Asymptomatic Carotid Artery Stenosis Study (ACAS) established the efficacy of carotid endarterectomy at large academic centers, there have been two community-based studies of outcomes after this operation. The purpose of this study was to perform a statewide survey to evaluate postoperative morbidity and mortality after carotid endarterectomy among patients throughout Maine. METHODS A statewide registry was established to collect prospective data on carotid operations from January 1 to December 31, 1995. All surgeons and hospitals in the state were solicited to participate. All carotid endarterectomies were intended to be included; the only exclusion criterion was out-of-state residence. Comorbidities, preoperative studies, surgical indications, operative technique, and postoperative outcomes were analyzed. State administrative data were used to assess registry coverage. RESULTS Ten of 17 hospitals participated, and 58% of all carotid endarterectomies performed in the state were included. Three hundred sixty-four operations were entered into the registry. Forty-four percent of the operations were performed for transient ischemic attack, 37% for asymptomatic stenosis, and 19% for stroke. The postoperative stroke rate was 2.5% with a total neurologic complication rate of 4.7% (transient ischemic attack and stroke). There was one postoperative death (mortality rate 0.3%). Patients with symptoms had a higher incidence of postoperative stroke (4.0% vs 0% asymptomatic; p < 0.05) and transient ischemic attacks (3.8% vs 0.8% asymptomatic). Hospital stroke rates varied from 0% to 7%. Stroke rate did not differ significantly between low-volume hospitals (2 to 28 patients/year, 3.3%) and high-volume hospitals (29 to 101 patients/year, 2.3%) or between low-volume surgeons (fewer than 11 operations/year, 1.7%) and high-volume surgeons (more than 12 operations/year, 2.4%). Among 26 reporting surgeons, stroke rate varied from 0% to 10%; the absolute number of strokes per surgeon varied between zero and two. CONCLUSION The statewide registry showed a postoperative stroke plus death rate of 2.8%, comparable with the NASCET and ACAS findings. Although this study had inherent limitations, the results from one state, including a variety of community practices, achieved results comparable with those of landmark trials.

Epidemiology and Short‐Term Outcomes of Injured Medicare Patients

Objectives: To describe characteristics and short‐term outcomes of Medicare patients hospitalized after injuries in 1999.

Initial presentation of older injured patients to high-volume hospitals is not associated with lower 30-day mortality in Medicare data.

Objective:To evaluate whether survival of older patients with severe injuries is positively associated with initial presentation to high-volume trauma hospitals. Design:Historical cohort study. Setting:We analyzed Medicare fee-for-service records. Cases were classified by maximum Abbreviated Injury Score (AISmax); those with isolated hip fractures or AISmax <3 were excluded. The initial hospital (emergency department or inpatient) for each case was classified by its number of included inpatient cases. Patients:Patients aged ≥65 with principal injury diagnoses (ICD-9 800–959, excluding 905, 930–939, 958) admitted to hospitals or who died in emergency departments during 1999. Interventions:None. Measurements and Main Results:Thirty-day mortality was determined using Medicare denominator data and modeled as a function of hospital volume, AISmax, age, gender, and comorbidity. We found that 95,867 patients (74,894 AISmax = 3; 17,932 AISmax = 4; 3,041 AISmax = 5) were managed in 4,391 hospitals. More than 90% of the interhospital transfers were from emergency departments, mostly from low-volume to high-volume hospitals, and were more frequent with greater severity. Regression models showed no difference in 30-day survival between patients taken first to low-volume hospitals (and possibly transferred) vs. patients taken directly to high-volume hospitals. Prior studies showing a positive or negative effect of hospital volume on survival of older patients could be replicated but their findings could not be generalized. Conclusions:Existing systems of trauma care result in similar survival for older patients with serious injuries seen first at low-volume or high-volume hospitals.

Injuries among older Americans with and without Medicare.

OBJECTIVES We evaluated the generalizability of Medicare fee-for-service data for patients hospitalized with injuries. METHODS We used 1998-2000 Medicare hospitalization data and National Hospital Discharge Survey (NHDS) data to analyze patients aged 65 years and older with principal injury diagnoses. RESULTS Demographics and injury patterns were similar in Medicare data and NHDS Medicare data. Injured patients without Medicare or health maintenance organization coverage were younger, less likely to have hip fractures, and more likely to have head or chest injuries. Mortality and discharge to long-term care were not significantly affected by insurance coverage, after we controlled for injury type and severity, age, gender, and comorbidity. Medicare patients had slightly longer hospital lengths of stay. CONCLUSIONS Hospital outcomes are generally similar among older patients with a given anatomic injury, regardless of insurance coverage.

A Multi-state Piecewise Exponential Model of Hospital Outcomes after Injury

Abstract To allow more accurate prediction of hospital length of stay (LOS) after serious injury or illness, a multi-state model is proposed, in which transitions from the hospitalized state to three possible outcome states (home, long-term care, or death) are assumed to follow constant rates for each of a limited number of time periods. This results in a piecewise exponential (PWE) model for each outcome. Transition rates may be affected by time-varying covariates, which can be estimated from a reference database using standard statistical software and Poisson regression. A PWE model combining the three outcomes allows prediction of LOS. Records of 259,941 injured patients from the US Nationwide Inpatient Sample were used to create such a multi-state PWE model with four time periods. Hospital mortality and LOS for patient subgroups were calculated from this model, and time-varying covariate effects were estimated. Early mortality was increased by anatomic injury severity or penetrating mechanism, but these effects diminished with time; age and male sex remained strong predictors of mortality in all time periods. Rates of discharge home decreased steadily with time, while rates of transfer to long-term care peaked at five days. Predicted and observed LOS and mortality were similar for multiple subgroups. Conceptual background and methods of calculation are discussed and demonstrated. Multi-state PWE models may be useful to describe hospital outcomes, especially when many patients are not discharged home.