Wide variations in cardiac stress testing, including imaging, plagues VA hospitals

Veteran’s Health Administration (VA) facilities vary widely in their use of cardiac stress tests among patients with ischemic heart disease (IHD), according to a new study published in JACC: Cardiovascular Imaging.

“Quantifying facility-level variation in cardiac stress test utilization is important for healthcare systems seeking to improve the efficiency and quality of cardiovascular care,” wrote first author Nishant R. Shah, MD, MPH, with Michael E. DeBakey Veterans Affairs Medical Center in Houston, and colleagues. “Limited registry and payer data suggest such variation may be wide, but benchmark data from a single, large health care system are lacking.”

Shah and co-authors used VA datasets to identify 994,929 patients (primary white men; mean age of 72 years) with IHD who had a primary care visit at the VA during 2014. Eighty-two percent of patients had hypertension and nearly half had diabetes. Patients with metastatic cancer, those in hospice care or missing date of birth or gender information were excluded.

Cardiac stress test utilization was defined as the number of tests performed per 100 IHD patients per year at each of the 130 VA centers, which included exercise treadmill testing (ETT), stress echocardiography and stress myocardial perfusion imaging. Facility-level variation was calculated using median rate ratios (MRRs), including models that adjusted for multiple variables.

Overall, the team found 40% residual facility-level variation in cardiac stress test utilization, Shah et al. wrote. Unadjusted stress test utilization ranged from 2.1 to 31.7 studies per 100 patients, and unadjusted MRR for overall stress test utilization was 1.69. After adjusting for patient-level characteristics, MRR fell to 1.40.

Additionally, variation between facilities was similar between ETT and imaging-based tests, the authors noted.

“Our data suggest that even after adjustment for patient mix, there is significant unexplained residual variation in cardiac stress test utilization in veterans with IHD,” the authors wrote. “These are the first benchmark data from a large, nationwide healthcare system.”

There could be a host of factors to explain the widespread variation in stress test utilization, according to the researchers, including overuse or misuse that may stem from a lack of appropriate use criteria awareness or even habits brought over from time outside of the VA.

Facility-level variables such as onsite availability of invasive cardiac catherization and cardiac CTA could have affected stress test referrals, and future research should take this into account, Shah et al. wrote.

“In conclusion, we found 40% residual facility-level variation in cardiac stress test utilization within the VA,” Shah and colleagues wrote. “Further contextualization with relevant patient/provider/facility-level variables, appropriateness, and patient outcomes could meaningfully improve efficiencies in and the quality of veterans’ cardiovascular care.”