Background/Purpose: The 2016 Infectious Disease Society of America (IDSA) guidelines recommend serologic screening for coccidioidomycosis (Cocci) prior to initiation of biologic response modifiers (BRMs). Current screening practices for Cocci in endemic communities have not been described. Our objective was to estimate serologic screening rates for Cocci by state, medication class, physician specialty (rheumatologist vs. non-rheumatologist), and by year.

Methods: In a retrospective cohort study using 2011-2015 Medicare claims data (a 5% representative sample), we identified fee-for-service beneficiaries residing in 7 endemic states (Arizona, California, New Mexico, Nevada, Texas, Utah, and Washington), with any of 10 rheumatic/autoimmune diseases (RA, PsA, AS, SLE, ReA, PM/DM, SSc, Psoriasis, IBD). We included beneficiaries with at least one prescription for a BRM, DMARD, and/or CS between 2012-2015 with continuous Parts A and B coverage in the 365 days preceding the prescription date in the analysis. Screening was considered current if the beneficiary had undergone serologic screening 365 days prior to the prescription date. Logistic regression was used to estimate the proportion of prescriptions that were current for serologic screening, by state, medication class, physician specialty, and by year, with 95%CIs. A sensitivity analysis was conducted to assess the serologic screening rate for newly initiated BRMs, defined as no supply of BRMs within the past 365 days. Generalized estimating equations were used to account for prescriptions written by the same provider.

Results: Among 296,987 prescriptions for 19,109 beneficiaries filled across the 7 endemic states, 3,004 had current serologic screening. In Arizona, 10.6% (95%CI: 8.6, 12.9) of all prescriptions (n=19,822) were current for serologic screening, compared to less than 1% in the other 6 states, prompting us to focus on Arizona for remaining analyses. Prescriptions for BRMs, CSs, and DMARDs had current screening for 20.6% (95% CI: 15.2, 27.4), 8.8% (95% CI:7.2, 10.8), and 9.5% (95%CI: 7.6, 11.9), respectively. Screening rates for BRMs increased from 18.7% (95%CI: 11.3, 29.4) in 2012 to 28.5% (95%CI: 20.2, 38.5) in 2015. Rheumatologists and non-Rheumatologists screening practices were similar (Table 1). Screening prior to newly initiated BRMs was 27.8% (95%CI:19.8, 37.6) in a limited sample (n=115).

Conclusion: Serologic screening rates for Cocci among Medicare beneficiaries with rheumatic/autoimmune diseases on BRMs, CSs, and DMARDs was low in the 7 endemic states, with almost no screening outside of Arizona. IDSA guidelines recommend Coccidioides serologic screening prior to initiation of BRMs, though not repeated annual serologic screening. Further, while the IDSA guidelines recognized increased risk of disseminated Cocci with use of CSs, no screening recommendations have been issued.