Population Variations in Rheumatoid Arthritis Treatment and Outcomes, Northern California, 1998-2009.

Herrinton LJ1, Harrold L2, Salman C3, Liu L4, Goldfien R5, Asgari M6, Gelfand JM7, Wu JJ8, Curtis JR9.

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Abstract

OBJECTIVE:

To assess variations in rheumatoid arthritis treatment and outcomes at the community level from 1998 through 2009.

METHODS:

The study used computerized data from 16 Kaiser Permanente Northern California Medical Centers. Mixed modeling was used to assess patterns across time and clinic. The analysis accounted for patient demographics, clustering of patients within Medical Centers, and repeated measures of patients over time. The metric used to measure drug use, months of use per patient per year, included both users and nonusers in the denominator, to account for both prevalence and duration of use.

RESULTS:

Assessment was performed of 28,601 patients with rheumatoid arthritis, with all levels of severity. From 1998 through 2009, methotrexate use doubled in the typical patient to include 23% of the time they were observed; sulfasalazine and hydrochloroquine use declined. By 2008 through 2009, leflunomide and antitumor necrosis factor agents were used by the typical patient 4% and 9% of the time, respectively. Between 1998 and 2009, disease-modifying antirheumatic drug use increased in the typical patient from 38% to 63% of the time, and oral prednisone use declined from 23% to 15% of the time, whereas opioid use initially rose but then fell to 23% of the time. No variations over time were observed for the rate of hospitalized pneumonia or opportunistic infection. Variation across clinics, measured by the difference in drug use between clinics at the 75th and 25th percentiles, was lowest for opioids (25% vs 20% of the time) and greatest for infliximab (< 1% to 3%).