Trends in DMARD prescribing by rheumatologists, NPs, and PAs among medicare beneficiaries, 2013-2023: an observational retrospective cohort study.

To understand the roles of physician associates [PAs] and nurse practitioners [NPs] in rheumatology care delivery, we examined the pharmacoepidemiology of disease-modifying antirheumatic drug [DMARD] prescriptions among Medicare beneficiaries. The intent was to inform regulatory decisions, optimize prescribing, and better manage risk in older populations. An observational, retrospective cohort study of Medicare Part D claims from 2013 to 2023 compared rheumatologist prescribers with primary care providers (family practice [FP] and internal medicine [IM]) and with PAs and NPs. Trends in DMARD prescriptions and prescriber counts were reported as absolute numbers and percentages and presented graphically. Over the 10-year period from 2013 to 2023, 13 of the most commonly prescribed DMARDs in Medicare Part D claims were tracked. Methotrexate was the most frequently prescribed, followed by hydroxychloroquine. The share of DMARD claims by rheumatologists remained relatively steady (58-60%) during this period, whereas the shares for PAs and NPs increased. Expressed as unique prescriber counts, the trends are even stronger: in 2013, NPs and PAs represented 6.7% and 4.2% of DMARD prescribers, respectively, increasing to 19.2% and 8.9% by 2023, while the percentages of IM and FP physicians declined from 45.7% to 35.8% to 32.7% and 30.0%, respectively, during this same period. DMARD prescriptions for the Medicare population increased from 2013 to 2023, with NPs and PAs assuming a growing role in prescribing.