Low-Value Back Imaging in the Care of Medicare Beneficiaries: A Comparison of Nurse Practitioners and Physician Assistants.

Little is known about practice pattern differences between nurse practitioners (NPs) and physician assistants (PAs). We compared the rates of low-value back images ordered by NPs and PAs. For this comparison, we used 2012-2013 Medicare Part B claims for all beneficiaries in 18 hospital referral regions and a measure of low-value back imaging from the Choosing Wisely recommendations. Models included a random clinician effect and fixed effects for beneficiary age, disability, Elixhauser comorbidities, clinician type, the emergency department setting, and region. NPs (N = 234) order low-value back images significantly less than PAs (N = 204) (NPs 25.5% vs. PAs 39.2%, p < .0001). Controlling for relevant factors, NPs are 10.0 percentage points (p < .0001) less likely to order a low-value back image than PAs. NPs and PAs have distinct patterns of low-value back imaging, which is likely a reflection of their different practice settings.