Background/Purpose: To determine total and subspecialty physician encounters, emergency room (ER) visits and hospitalizations in an incident cohort of rheumatoid arthritis (RA) cases and matched control patients over 13 years.

Methods: A retrospective cohort study was performed utilizing administrative health care data from approximately 1 million people with access to universal healthcare. Using ICD-9 and ICD-10 diagnostic codes, 7 RA case definitions were used. Each case was matched by age and gender to 4 randomly selected controls. Data included physician billings, ER visits and hospital discharges over 13 years.

Results: The number of incident RA cases varied from 3,460 to 27,657 depending upon the case definition. The mean (SD) age was 56.0 (17.8) years and the proportion of females was 68%. Using a single representative case definition for RA, the utilization of different services in the index year and after 13 years of follow-up is summarized in Table 1. All encounters with physicians and services by RA patients were significantly higher than controls (p<0.0001 for all) and were highest in the index year, declining thereafter. Over 13 years the reduction in utilization varied by service from 78% (Rheumatologists; p<0.0001), 54.7% (Internal medicine; p<0.0001), 17.1% (primary care physicians; p<0.0001), 9.2% (other physicians; p<0.0001), 30.2% (ER visits; p<0.01) and 63% (hospitalizations; p<0.0001). Table 1: Utilization of physician and clinical services by RA patients and controls

Conclusion: In RA patients, health care utilization is highest in the first year following the diagnosis which is also the time of maximal involvement by rheumatologists. Utilization declines over time and encounters with patient’s primary care and other physician groups predominate.