Time to Initiation of DMARDs among Patients with RA

San Francisco—Rheumatoid arthritis (RA) is a chronic, inflammatory disorder characterized by pain, progressive disability due to inflammation, and joint destruction. Patients with RA often face daunting economic and comorbid burdens. Most pharmacologic management of RA consists of complex regimens of conventional or biologic or disease-modifying antirheumatic drugs (DMARDs) as well as concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids. DMARDs improve quality of life for RA patients by controlling disease activity and decreasing erosion of joints. The American College of Rheumatology guidelines recommend that most patients begin treatment with DMARDs within 3 months of diagnoses in order to slow progression of the disease.

The objectives of this study, presented at an AMCP poster session, were to evaluate the time to DMARD initiation in newly diagnosed commercially-insured RA patients and to examine whether initiation time varied across different patient characteristics among these patients. The poster was titled Time to Disease-Modifying Antirheumatic Drug Initiation among Newly Diagnosed Rheumatoid Arthritis Patients.

Data for the study were taken from the 2003-2009 Thomson Reuters MarketScan® Commercial and Medicare Research Databases, which contain administrative healthcare data for >63 million individuals ≥18 years of age from >130 health plans across the United States. The overall study period was January 1, 2003, to September 30, 2009. Continuous enrollment requirement was 12 months pre- and postindex. There was a minimum of 12 months follow-up postindex. Inclusion criteria were at least 2 inpatient or outpatient nondiagnostic claims for RA between January 1, 2004, and October 1, 2008.

A total of 26,911 patients met the study criteria. Mean age (SD) of patients was 59.7 (14.1) years; 71.7% were female. Of these, 17,014 patients (63%) initiated DMARD therapy in the follow-up period. Of those who initiated DMARD therapy, 86.9% did so within 90 days of diagnosis, 8.2% did so 91 to 180 days after diagnosis, and 4.9% did so 181 to 365 days after diagnosis.

On the Kaplan-Meier plot, median time to conventional DMARD was 65 days. Approximately 20% of RA patients initiated conventional DMARDs immediately at time of diagnosis, while initiation of biologic DMARDs increased steadily over the year. According to the Cox regression model, occurrence of a rheumatoid factor test, a rheumatologist visit, NSAID use, corticosteroid use, and lower comorbid burden as measured by the Charlson/Deyo Comorbidity Index were all associated with short time to DMARD initiation (P<.001 for each factor).

Approximately 65% of patients with a rheumatologist visit during the preindex period (n=3903) initiated a DMARD within 3 months after diagnosis, compared with 53% of patients who did not visit a rheumatologist. DMARD initiation within 3 months after diagnosis was achieved by 57% of patients with a Charlson/Deyo Comorbidity Index of 0, by 54% with a score of 1, by 51% with a score of 2, and by 47% with a score ≥3.

The investigators cited several limitations. The study was limited to those with commercial health coverage or Medicare supplemental coverage; it is unknown whether these results can be generalizable to the greater U.S. population. Those who are uninsured or underinsured may have different rates of DMARD initiation than those whose data was analyzed in the study. In addition, the database used in the study does not include information on patient race, ethnicity, or socioeconomic status, all of which may influence DMARD initiation.