Relationships between driving distance, rheumatoid arthritis diagnosis, and disease-modifying antirheumatic drug receipt

Abstract

Objective: Disease-modifying antirheumatic drugs (DMARDs) are recommended for all patients with rheumatoid arthritis (RA). Some estimate that approximately one-half of patients with RA do not receive DMARDs. We hypothesized that patients with RA living farther from rheumatologists would be less likely to receive RA diagnoses and to receive DMARDs.

Methods: US-based Medicare patients ages >65 years were study eligible. We calculated driving distance from patients' homes to the nearest rheumatologist. Using multivariable logistic regression, we assessed relationships between driving distance and RA diagnosis and between driving distance and DMARD receipt. In one set of analyses, distance was divided into quartiles: 0-2, 2.1-5, 5.1-15.9, and ≥16 miles. In a second set of analyses, we used predefined categories: 0-15, 15.1-30, 30.1-60, and >60 miles.

Results: Among 59,426 Medicare beneficiaries, 918 had diagnosed RA. Compared to the first quartile, increased distance was associated with decreased odds of RA diagnosis (odds ratio [OR] 0.96 [95% confidence interval (95% CI) 0.80-1.16] in second quartile, OR 0.88 [95% CI 0.72-1.07] in third quartile, and OR 0.72 [95% CI 0.56-0.93] in fourth quartile; P < 0.01 for trend). Similar results were observed using predefined categories. Among those with RA, increased distance was associated with increased odds of DMARD receipt across quartiles (OR 1.15 [95% CI 1.06-1.25] in second quartile, OR 1.41 [95% CI 1.29-1.54] in third quartile, and OR 1.32 [95% CI 1.18-1.46] in fourth quartile; P = 0.001 for trend). There was no relationship between predefined categories and DMARD receipt (P = 0.45 for trend).

Conclusion: Increased driving distance to rheumatologists was associated with decreased odds of RA diagnosis. Among those with diagnosed RA, the odds of DMARD receipt rose as distance increased from <2 to 16 miles, but not beyond. Urban residents living closer to rheumatologists may have barriers to DMARD use besides geographic access.