Utilization, cost, and provider trends in patch testing among Medicare beneficiaries in the United States from 2012 to 2017.

ABSTRACT Background Patch testing is the best diagnostic test for allergic contact dermatitis. However, there is presently a lack of data on the test's geographic availability and the characteristics of the providers offering this test across the United States. Objective To evaluate the geographic variation in the availability of patch testing for the Medicare population and to characterize the temporal trends of patch testing cost, utilization, and provider specialty from 2012-2017. Methods Retrospective cohort study of the Medicare Provider Utilization and Payment Data from 2012-2017. Results: As of 2017, patch testing was available in 20.3% of metropolitan counties and in 1.1% of non-metropolitan counties. From 2012-2017 in metropolitan regions, the number of beneficiaries tested by dermatologists grew by an average annual growth rate (AAGR) of 1.84% while those tested by allergists grew by an AAGR of 20.31%. Most providers that averaged use of ≥80 patches per beneficiary were dermatologists (76.3%). Limitations: Analysis restricted to Medicare Part B claims; data unavailable on individuals with commercial insurance. Conclusions Most of the increase in patch testing utilization from 2012-2017 has been in metropolitan regions. While growth was especially prominent among allergists in metropolitan counties, the majority of providers performing comprehensive patch testing were dermatologists.