Andrea E. Siewers

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.

Race and Surgical Mortality in the United States

Objective:This study describes racial differences in postoperative mortality following 8 cardiovascular and cancer procedures and assesses possible explanations for these differences. Summary Background Data:Although racial disparities in the use of surgical procedures are well established, relationships between race and operative mortality have not been assessed systematically. Methods:We used national Medicare data to identify all patients undergoing one of 8 cardiovascular and cancer procedures between 1994 and 1999. We used multiple logistic regression to assess differences in operative mortality (death within 30 days or before discharge) between black patients and white patients, controlling for patient characteristics. Adding hospital indicators to these models, we then assessed the extent to which racial differences in operative mortality could be accounted for by the hospital in which patients were cared for. Results:Black patients had higher crude mortality rates than white patients for 7 of the 8 operations, including coronary artery bypass, aortic valve replacement, abdominal aortic aneurysm repair, carotid endarterectomy, radical cystectomy, pancreatic resection, and esophagectomy. Among these 7 procedures, odds ratios of mortality (black versus white) ranged from 1.23 (95% confidence interval, 1.18–1.29) for CABG to 1.61 (95% confidence interval, 1.28–2.03) for esophagectomy. Adjusting for patient characteristics had modest or no effect on odds ratios of mortality by race. However, there remained few clinically or statistically significant differences in mortality by race after we accounted for hospital. Hospitals that treated a large proportion of black patients had higher mortality rates for all 8 procedures, for white as well as black patients. Conclusions:Black patients have higher operative mortality risks across a wide range of surgical procedures, in large part because of higher mortality rates at the hospitals they attend.

Surgeon Volume and Operative Mortality in the United States

Objectives:Although recent studies suggest that physician age is inversely related to clinical performance in primary care, relationships between surgeon age and patient outcomes have not been examined systematically. Methods:Using national Medicare files, we examined operative mortality in approximately 461,000 patients undergoing 1 of 8 procedures between 1998 and 1999. We used multiple logistic regression to assess relationships between surgeon age (≤40 years, 41–50 years, 51–60 years, and >60 years) and operative mortality (in-hospital or within 30 days), adjusting for patient characteristics, surgeon procedure volume, and hospital attributes. Results:Although older surgeons had slightly lower procedure volumes than younger surgeons for some procedures, there were few clinically important differences in patient characteristics by surgeon age. Compared with surgeons aged 41 to 50 years, surgeons over 60 years had higher mortality rates with pancreatectomy (adjusted odds ratio [OR], 1.67; 95% confidence interval [CI], 1.12–2.49), coronary artery bypass grafting (OR, 1.17; 95% CI, 1.05–1.29), and carotid endarterectomy (OR, 1.21; 95% CI, 1.04–1.40). The effect of surgeon age was largely restricted to those surgeons with low procedure volumes and was unrelated to mortality for esophagectomy, cystectomy, lung resection, aortic valve replacement, or aortic aneurysm repair. Less experienced surgeons (≤40 years of age) had comparable mortality rates to surgeons aged 41 to 50 years for all procedures. Conclusions:For some complex procedures, surgeons older than 60 years, particularly those with low procedure volumes, have higher operative mortality rates than their younger counterparts. For most procedures, however, surgeon age is not an important predictor of operative risk.

Is surgery getting safer? National trends in operative mortality.

BACKGROUND Although mortality rates for some cardiovascular procedures seem to have declined, it is unclear whether other high-risk procedures are becoming safer over time. STUDY DESIGN We examined national trends between 1994 and 1999 in operative mortality for 14 high-risk cardiovascular and cancer procedures in the national population of Medicare beneficiaries over age 65. Secular trends were examined using logistic regression adjusting for age, gender, race, socioeconomic status, admission acuity, comorbidities, and hospital volume. RESULTS Observed mortality rates varied widely across the 14 procedures, from 2% (carotid endarterectomy) to 16% (esophagectomy). Over the 6-year study period, average patient age increased for all procedures, and patients were more likely to undergo operation at high-volume hospitals for some procedures (pancreatic resection, esophagectomy, cystectomy, and pneumonectomy). After accounting for these changes, operative mortality declined significantly for three cardiovascular procedures, as evidenced by adjusted odds ratios (OR) for the 6-year effect on operative mortality (coronary artery bypass graft OR = 0.85, 95% confidence interval [CI] 0.81 to 0.88; carotid endarterectomy OR = 0.86,95% CI 0.80 to 0.93; mitral valve replacement OR = 0.89, 95% CI 0.81 to 0.97). In contrast, operative mortality did not decline for any of the cancer procedures. In fact, adjusted mortality increased for colectomy for colon cancer (OR= 1.13, 95% CI 1.07 to 1.19). CONCLUSIONS Although risks of some cardiovascular procedures are declining over time, there is no evidence that other types of high-risk surgery are becoming safer. These findings suggest the need for systematic efforts to monitor and improve surgical performance.

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).

Perioperative and long-term prognostic value of dipyridamole Tc-99m sestamibi myocardial tomography in patients evaluated for elective vascular surgery.

BackgroundPatients with peripheral vascular disease are at increased risk for perioperative and long-term cardiac morbidity and mortality. Substantial data exist supporting the use of preoperative clinical risk stratification and planar thallium myocardial scintigraphy. Only limited data are available assessing the role of technetium-99m (Tc-99m) single photon emission computed tomography (SPECT) for preoperative evaluation in this population.>/<Methods and ResultsIn our study 153 patients who underwent peripheral vascular surgery were followed up for up to 4 years after preoperative dipyridamole Tc-99m sestamibi SPECT to determine clinical and SPECT predictors of perioperative and long-term adverse cardiac events by multivariate analysis. There were no statistically significant clinical or SPECT predictors of perioperative risk, although no perioperative events occurred in patients with normal scans. Abnormality in the left anterior descending (LAD) territory (risk ratio = 3.1; 95% confidence interval, 1.4–7.1) was the only statistically significant univariate predictor of long-term death or myocardial infarction. Only abnormality in the LAD territory appeared to improve model fit beyond clinical risk (risk ratio = 2.9; 95% confidence interval, 1.2–7.3; P = .02).>/<ConclusionsPatients with normal preoperative scans have a low risk of perioperative cardiac events and may safely undergo peripheral vascular surgery without further coronary intervention. However, scan abnormality in the LAD distribution confers poor long-term prognosis, suggesting that patients with this finding before peripheral vascular surgery should receive aggressive medical therapy and possibly invasive intervention to improve long-term survival.>/<

New Cardiac Surgery Programs Established From 1993 To 2004 Led To Little Increased Access, Substantial Duplication Of Services

Despite decreasing demand for bypass surgery, 301 new cardiac surgery programs opened between 1993 and 2004. We used Medicare data to identify where the new programs opened and to assess their impact on access and efficiency. Forty-two percent of the new programs opened in communities that already had access to cardiac surgery, which suggests that their creation has led to a fight for shares of a shrinking market. New programs were much more likely to open in states that did not require them to show a certificate-of-need. Overall, travel time to the nearest cardiac surgery program changed little, which suggests that these programs have done little to improve geographic access. The duplication of services that resulted in many areas may have engendered competition based on quality, price, or both, but it may also have increased surgical rates, with unknown results. We observe that certificate-of-need requirements may help avoid unnecessary duplication of services by preventing new programs from opening in close proximity to existing ones.

Characteristics of new cardiac surgery programs in the United States: Mitigating the learning curve

BACKGROUND New cardiac surgery programs continue to open across the United States, and it is not known how new programs deal with potentially low volumes during their start-up period. We compared patient, procedure, and physician characteristics and short-term mortality at established cardiac surgery programs, new programs in general hospitals, and new specialty cardiac hospitals. METHODS We used Medicare Provider Analysis and Review, part B physician claims, and denominator files to evaluate established and new programs performing coronary artery bypass graft surgery (CABG) from 1994-2003. Short-term mortality was defined as death in-hospital or within 30 days. RESULTS From 1994-2003, 257 new programs in general hospitals and 20 new specialty hospitals opened; and 884 established programs were in operation. New programs in general hospitals had much lower CABG volume than established programs and performed fewer concomitant valves and reoperations. New specialty hospitals had high CABG volume from inception, similar valve and reoperation rates to established programs, and conducted more elective procedures. Short-term mortality was significantly lower at new programs in general hospitals. CONCLUSIONS Start-up strategies used by new specialty hospitals and new programs in general hospitals differed markedly. By choosing to conduct safer procedures on low-risk patients, new general programs may have offset potential concerns about operating at low volume. Neither type of new program exhibited an increased risk of short-term mortality. The high volume at specialty hospitals may reassure patients and policy makers, although the high proportion of elective procedures and the new programs effect on surrounding hospitals require further consideration.

Hospital volume and surgical mortality in the United States

BACKGROUND Although numerous studies suggest that there is an inverse relation between hospital volume of surgical procedures and surgical mortality, the relative importance of hospital volume in various surgical procedures is disputed. METHODS Using information from the national Medicare claims data base and the Nationwide Inpatient Sample, we examined the mortality associated with six different types of cardiovascular procedures and eight types of major cancer resections between 1994 and 1999 (total number of procedures, 2.5 million). Regression techniques were used to describe relations between hospital volume (total number of procedures performed per year) and mortality (in-hospital or within 30 days), with adjustment for characteristics of the patients. RESULTS Mortality decreased as volume increased for all 14 types of procedures, but the relative importance of volume varied markedly according to the type of procedure. Absolute differences in adjusted mortality rates between very-low-volume hospitals and very-high-volume hospitals ranged from over 12 percent (for pancreatic resection, 16.3 percent vs. 3.8 percent) to only 0.2 percent (for carotid endarterectomy, 1.7 percent vs. 1.5 percent). The absolute differences in adjusted mortality rates between very-low-volume hospitals and very-high-volume hospitals were greater than 5 percent for esophagectomy and pneumonectomy, 2 to 5 percent for gastrectomy, cystectomy, repair of a nonruptured abdominal aneurysm, and replacement of an aortic or mitral valve, and less than 2 percent for coronary-artery bypass grafting, lower-extremity bypass, colectomy, lobectomy, and nephrectomy. CONCLUSIONS In the absence of other information about the quality of surgery at the hospitals near them, Medicare patients undergoing selected cardiovascular or cancer procedures can significantly reduce their risk of operative death by selecting a high-volume hospital.

Diagnostic-Therapeutic Cascade Revisited

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).