Abstract
OBJECTIVES: The authors aimed to analyze temporal trends in cardiac stress testing in U.S. Medicare beneficiaries from 2008 to 2012, types of stress testing, and comparative utilization related to the presence and severity of chronic kidney disease (CKD). BACKGROUND: A long-held perception depicts patients with CKD as being treated less intensively for cardiovascular disease than nonrenal patients. We wondered whether use of diagnostic testing for ischemic heart disease is affected by the presence of CKD. METHODS: Using the 20% Medicare sample, we assembled yearly cohorts of Medicare beneficiaries (∼4,500,000 per year) from 2008 to 2012. Beneficiaries 66 years or older undergoing a first cardiac stress test, with no previous history of coronary revascularization and no acute coronary syndrome within 60 days, were identified, as was the type of stress test. We analyzed temporal trends and compared testing rates related to CKD stage versus no CKD. A Poisson regression model estimated the likelihood of stress testing in 2012 by CKD stage, adjusted for demographic characteristics and comorbid conditions. RESULTS: Approximately 480,000 older patients (∼29,000 with CKD) underwent stress tests in 2008, progressively declining to ∼400,000 in 2012 (∼38,000 with CKD). In 2008 to 2012, 78% to 80% of all stress testing in non-CKD patients used nuclear imaging, as did 87% to 88% in CKD patients. Rates of stress testing declined progressively for non-CKD and CKD patients in 2008 to 2012: 11.5 to 9.4 per 100 patient-years and 16.8 to 13.4 per 100 patient-years, respectively. The adjusted Poisson model, with non-CKD as the reference, showed an increasing likelihood of stress testing with worsening CKD: incidence rate ratio 1.01 for stages 1 to 2 (p = NS), 1.05 for stage 3 (p < 0.0001), 1.01 for stage 4 (p = NS), 1.04 for stage 5 nondialysis (p = NS), and 1.15 for stage 5 dialysis (p < 0.0001). CONCLUSIONS: Overall rates of cardiac stress testing (over three-fourths using nuclear imaging) declined in 2008 to 2012 among Medicare beneficiaries 66 years or older but were consistently higher for CKD than for non-CKD patients. The effect of screening algorithms for transplant candidates was unknown. Our data refute underutilization of cardiac stress testing in CKD patients.