Comparison of Care Provided in Practices with Nurse Practitioners and Physician Assistants Versus Subspecialist Physicians Only: A Cohort Study of Rheumatoid Arthritis

Abstract

Objective The Affordable Care Act proposes wider use of nurse practitioners (NPs) and physician assistants (PAs), but little is known about outcomes of care provided by them in medical specialties. We compared the outcomes of care for patients with rheumatoid arthritis (RA) seen in practices with NPs or PAs and rheumatologists versus practices with rheumatologists only. Methods We enrolled 7 rheumatology practices in the US (4 with NPs or PAs and 3 without). RA disease activity (categorized as in remission, low, moderate, or high, using standardized measures) was abstracted from medical records from the most recent 2 years. We performed a repeated-measures analysis using generalized linear regression to compare disease activity for visits to practices with NPs or PAs versus rheumatologist-only practices, adjusting for disease duration, serologic status, RA treatments, and disease activity measures. Results Records from 301 patients, representing 1,982 visits, were reviewed. The patients' mean age was 61 years and 77% were female. In the primary adjusted analysis, patients seen in practices with NPs or PAs were less likely to have higher disease activity (odds ratio 0.32, 95% confidence interval 0.17-0.60; P = 0.004) than those seen in rheumatologist-only practices. However, there were no differences in the change in disease activity. Conclusion Patients seen in practices with NPs or PAs had lower RA disease activity over 2 years compared to those seen in rheumatologist-only practices; no differences were observed in the change in disease activity between visits either within or between the different types of provider practice.