Do imaging studies performed in physician offices increase downstream utilization? An empiric analysis of cardiac stress testing with imaging

Objectives: The goal of this study was to compare patterns of downstream testing and procedures after stress testing with imaging performed at physician offices versus at hospital-outpatient facilities Background: Stress testing with imaging has grown dramatically in recent years, but whether the location of where the test is performed correlates with different patterns for subsequent cardiac testing and procedures is unknown Methods: We identified 82,178 adults with private health insurance from 2005 to 2007 who underwent ambulatory myocardial perfusion imaging (MPI) or stress echocardiography (SE). Subsequent MPI, SE, cardiac catheterization or revascularization within 6 months was compared between physician office and hospital outpatient settings. Results: Overall, 85.1% of MPI and 84.9% of SE were performed in physician offices. The proportion of patients who underwent subsequent MPI, SE, or cardiac catheterization was not statistically different between physician office and hospital outpatient settings for MPI (14.2% vs. 13.9%, p = 0.44) or SE (7.9% vs. 8.6%, p = 0.21). However, patients with physician office imaging had slightly higher rates of repeat MPI within 6 months compared with hospital-outpatient imaging for both index MPI (3.5% vs. 2.0%, p < 0.001) and SE (3.4% vs. 2.1%, p < 0.001), and slightly lower rates of cardiac catheterization after index MPI (11.4% vs. 12.2%, p = 0.04) and SE (4.5% vs. 7.0%, p < 0.001). Differences in 6-month utilization were observed across the 5 healthcare markets after index MPI but not after index SE Conclusions: Physician office imaging is associated with slightly higher repeat MPI and fewer cardiac catheterizations than hospital outpatient imaging, but no overall difference in the proportion of patients undergoing additional further testing or procedures. Although regional variation exists, especially for MPI, the relationship between physician office location of stress testing with imaging and greater downstream resource utilization appears modest.