Background/Purpose: Disease-modifying antirheumatic drugs (DMARDs) are recommended for all patients with rheumatoid arthritis (RA). Some studies estimate that almost half of patients with RA do not receive DMARDs. Distance to the nearest rheumatologist, a proxy for access to care, may explain some variability. We hypothesized that patients with RA living further from a rheumatologist would be less likely to receive an RA diagnosis and to receive DMARDs.

Methods: We obtained a list of US rheumatologists from the American College of Rheumatology. Medicare patients with Parts A, B, and linked prescription data from CVS Caremark were 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, defined using procedures for claims data, and between driving distance and DMARD receipt in 365 days of follow-up. Secondary outcomes included receipt of ≥1 biologic DMARD, combination DMARD use (≥2 DMARDs for ≥60 days) and majority of time on DMARDs (days supply of ≥1 DMARD for ≥50% of days). In one set of analyses, distance was divided into quartiles: 0-2, 2.1-5.0, 5.1-15.9, ≥16 miles. In a second, we used pre-defined categories: 0-15, 15.1-30, 30.1-60, ≥60 miles.

Results: 26,590 patients had diagnosed RA. Compared to the first quartile, increased distance was associated with decreased odds of RA diagnosis: second quartile, OR=0.96 (95% CI, 0.80-1.16); third=0.88 (0.72-1.07); fourth=0.72 (0.56-0.93), p for trend=0.0099. Similar results were observed using pre-defined distance categories. Among those with RA, increased driving distance was associated with increased odds of any DMARD receipt across quartiles: second=1.15 (1.06-1.25); third=1.41 (1.29-1.54); fourth=1.32 (1.18-1.46), p for trend=0.0012.  There was no relationship between pre-defined categories and any DMARD receipt: 15.1-30 miles=1.09 (0.99-1.19); 30.1-60=1.03 (0.91-1.16); ≥60.1=1.06 (0.91-1.23), p for trend=0.4506. Similar results were observed for combination DMARD use, but not for biologic DMARD receipt or majority of time on DMARDs (Table). 

Conclusion: Increased driving distance to a rheumatologist was associated with decreased odds of RA diagnosis. Among those with diagnosed RA, the odds of DMARD use rose as distance increased from <2 to 16 miles, but not beyond, suggesting that urban residents who live closer to a rheumatologist may have other barriers to DMARD use.

Table.  Relative odds of DMARD use at 365 days, comparing the 2 approaches to define driving distance