Variability in utilization of diagnostic imaging tests in patients with symptomatic peripheral artery disease

Imaging can help guide management in peripheral arterial disease (PAD) with symptoms refractory to medical treatment. However, there are no set guidelines to determine when physicians should seek further imaging in patients with PAD for the assessment of new, persistent or worsening symptoms. This study describes the rates and variability in non-invasive and invasive imaging for patients presenting to vascular specialty clinics for symptomatic PAD.

Patients (n=1,275) with a new PAD diagnosis or exacerbation of PAD symptoms were enrolled from 16 vascular clinics. Hierarchical logistic regression models were used to estimate the referral rates for 1) non-invasive and 2) invasive imaging tests, after adjusting for patient demographics, disease characteristics, PAQ summary score, PAD performance measures and country. Median Odds Ratios (MOR) were calculated to examine the variability across sites and providers.

Mean ABI was 0.67 ± 0.19. There were 690 (54.1%) patients who had imaging, of which 62 (9.0%) had invasive imaging. Imaging rates ranged from 8.6% to 98.6% across sites. The MOR for use of imaging for site was 3.36 (p < 0.001) and provider 3.49 (p < 0.001). The variability was explained primarily by (R² = 29%) country followed by patient-level factors, provider and lastly site (R² = 17%, 14%, and 13%, respectively).

There is wide variation in the use of imaging for patients presenting with new onset or recent exacerbations of their PAD. Country, followed by provider and site, were most strongly associated with this variability after adjusting for patient characteristics.