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Physician Decision Making and Trends in the Use of Cardiac Stress Testing in the United States: An Analysis of Repeated Cross-Sectional Data | Journal Scan
Study Questions:
What are the causes for the upward trend in utilization of cardiac stress tests with respect to evolving patient demographics, cardiac risk factors, and provider characteristics?
Methods:
Data from the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) from 1993 to 2010 were evaluated. The study analysis included all visits to an outpatient clinic by adults (ages >18 years) without a prior diagnosis of coronary heart disease (CHD). The primary endpoint was identification of patients who were referred for or underwent cardiac stress testing including treadmill stress testing alone, bicycle ergometry, and stress test imaging. Low-risk patients were defined as those without cardiac risk factors and in whom the reason for physician visit was something other than chest pain. Appropriate use criteria were applied to the patient cohorts.
Results:
The rate of cardiovascular stress testing increased from 28 per 10,000 visits in 1993-1995 to 42 per 10,000 visits in 2001-2003, and to 45 per 10,000 visits in 2008-2010. These rates are based on a calculated total of 1.6 million visits per year in 1993-1995, 3.2 million visits per year in 2001-2003, and 3.8 million visits per year in 2008-2010. The trend to more frequent testing in unadjusted analysis was significant (p < 0.01). This trend was not significant after adjustment for changes in patient characteristics, clinical risk factors, and provider characteristics. This trend was largely contributed to by an increase in the proportion of male patients, patients’ age 45-64 years, patients with private insurance or Medicare, and patients seeing cardiologists or with newly diagnosed hypertension, diabetes, or dyslipidemia. The percentage of tests performed with concurrent imaging increased from 59% to 87% to 87% in the three time periods (p < 0.001), and could not be explained by variation in patient demographics, risk factors, or provider characteristics. For tests performed between 2005 and 2010, 30% of stress tests with imaging were considered as “rarely appropriate,” as per appropriate use criteria. Subgroup analysis revealed that after adjustment for patient characteristics, there was a significant upward trend in utilization of stress tests for women (p = 0.045), patients ages 65-79 years (p = 0.008), patients who presented with chest pain (p = 0.033), and patients under the care of a cardiologist (p = 0.043). The percentage of stress tests with concurrent imaging was higher in women (73%) than men (46%) in the early 2-year period, but was absent from 2001 and onward. There was no evidence of lower likelihood of cardiovascular stress testing being requested in black patients compared to white, but there was a nonsignificant lower stress test rate in Hispanic patients.
Conclusions:
Overall national growth in cardiovascular stress testing is largely attributable to changes in patient population demographics and provider characteristics, whereas addition of imaging to cardiovascular stress testing is not explained by these factors. There was no evidence of physician decision making contributing to racial or ethnic disparities in cardiovascular testing.
Perspective:
Growth in utilization of cardiovascular imaging in stress testing has been well documented and has been of concern with respect to cost containment and delivery of medical care in the United States. This study outlines a number of factors which contribute to the increase in trend in cardiovascular stress testing done between the years 1993 and 2010, and demonstrates that for the entire population cohort, the trend can be explained by changes in patient demographics, cardiovascular risk factors, and provider characteristics (cardiologists vs. noncardiologists). The study also nicely demonstrates a dramatic increase in the proportion of stress tests performed with concurrent stress test imaging, which could not be explained by alteration of patient demographics or clinical risk factors. The authors did identify subsets for whom demographics and risk factors alone did not explain the upward trend, including women and patients in the age range 65-79 years. There are several messages to take from this study, including the fact that the overall upward trend in cardiovascular stress testing may be appropriate, based on a worsening profile of patient characteristics. Other upward trends including those in female patients may be directly related to the enhanced recognition of atypical CHD presentations in women, which may inadvertently result in a disproportionate increase in cardiovascular stress testing in female versus male patients over this time period. The authors’ analysis suggested that approximately one in three cardiovascular stress tests were unlikely to be appropriate. This number must be viewed with some concern, as the validity of data available in a large database such as this may not allow accurate determination of clinical decision making with respect to reasons for providing a stress test.
Keywords: African Americans, African Continental Ancestry Group, Chest Pain, Cost Control, Decision Making, Demography, Diabetes Mellitus, Dyslipidemias, Exercise Test, Health Care Surveys, Hispanic Americans, Hypertension, Medicare, Risk Factors
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