Association of Patient, Prescriber, and Region With the Initiation of First Prescription of Biologic Disease-Modifying Antirheumatic Drug Among Older Patients With Rheumatoid Arthritis and Identical Health Insurance Coverage

Abstract

Importance: Prescribing the first biologic treatment for rheumatoid arthritis (RA) is an important decision for patients, their physicians, and payers, with considerable costs and clinical implications. Conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) have known effectiveness and safety profiles and are less expensive; therefore, determining the variables contributing to csDMARD treatment duration is an essential question for patients, physicians, and payers.

Objectives: To describe access to the first biologic DMARD prescription in a population of patients with RA and identical comprehensive health insurance coverage in Ontario, Canada, and to explore the associations of patient, prescriber, and geographic region with differences in time to first biologic prescription.

Design, setting, and participants: This cohort study of incident patients with RA used administrative data with surveillance and patient-level data collected at yearly intervals. A total of 17 672 patients were included in the study; they were residents of Ontario, Canada, had an incident RA diagnosis at age 67 or older between 2002 and 2015, and received at least 1 csDMARD. Data were analyzed in November 2017.

Exposure: Patient variables were age, sex, disease duration, socioeconomic status, distance to care, and supply of care in the patient's area of residence. Prescriber covariates were year of graduation, specialty of practice, and supply of rheumatologic care in the patient's geographic region.

Main outcomes and measures: Time from first csDMARD prescription to receipt of first biologic medication.

Results: Of 17 672 patients, 11 598 (65.6%) were women, and the mean (SD) age was 75.2 (5.8) years. Characteristics associated with longer time to receipt of a biologic prescription were older age (HR for every 5-year increase, 0.66; 95% CI, 0.62-0.71; P < .001), male sex (HR, 0.76; 95% CI, 0.66-0.89; P < .001), and distance to the nearest rheumatologist (HR per 10-km increase, 0.99; 95% CI, 0.98-0.99; P < .001). Prescribers were primarily rheumatologists (151 of 214 [70.6%]) and primary care physicians (26 of 214 [12.1%]). After adjusting for the number of patients eligible to receive biologic DMARDs, rheumatologists' preferences (ie, yearly prescription rates) for using biologic DMARDs increased over time, from 1.7% in 2001 to 4.9% in 2015. After adjusting for calendar year and patient-, prescriber-, and region-level characteristics, substantial variation between prescribers in rates of prescribing a first biologic DMARD were found (65% variance).

Conclusions and relevance: This study found variation in time to receipt of first biologic DMARD after prescription of first csDMARD in a population with RA after adjustment for individual-level patient, prescriber, and geographic area covariates, despite identical universal health insurance coverage.

Figure 1.. Active Biologic Prescription Percentage as a Proportion of Active Users of All Disease-Modifying Antirheumatic Drugs (DMARDs) Among Older Adults With Rheumatoid Arthritis

Unadjusted proportion of all patients older than 65 receiving biologic DMARD for rheumatoid arthritis, by region.

Figure 2.. Time From First Conventional Synthetic Disease-Modifying Antirheumatic Drug (csDMARD) to First Biologic DMARD Among Older Adults With Rheumatoid Arthritis in Ontario, Canada, Stratified by Region

Unadjusted survival curves for patients older than 67 years who started their first csDMARD prescription between 2002 and 2015, inclusive, with a maximum follow-up to 2017. The shaded area around the aggregate curve represents the 95% CI.

Figure 3.. Quantity-Adjusted Supply of Rheumatologists by Region

Vertical line represents the change in rheumatologist billing identifier code.

Figure 4.. Biologic Prescription Preferences Among 270 Physicians Who Prescribed Biologic Disease-Modifying Antirheumatic Drugs Over Time

Preference computed using all available patients. Dots represent individual physicians.