ATLANTA – Nonbiologic disease-modifying anti-rheumatic drugs – particularly methotrexate – and treat-to-target strategies are at least as responsible as are biologic agents for improvements in the control of rheumatoid arthritis over the last 2 decades.
Data from 1989 to 2008 for 992 patients from the Nijmegen Inception Cohort of patients with newly diagnosed RA showed that the use of biologics increased from 0% around 2000 to 22%, Dr. Wietske Kievit reported at the annual meeting of the American College of Rheumatology.
During the same time period, the use of sulfasalazine decreased from 60% to 16%, with the greatest decline beginning around 2000. Also, the use of methotrexate increased from about 5% to 62%, with the sharpest increases occurring before the biologic era.
"We also saw an increase in the mean dose of methotrexate in the population; in 1989, the mean dose was almost 7 [mg/week] with a maximum of 7.5, and in 2008, the mean dose was 16 with a maximum dose of 30," said Dr. Kievit of Radboud University Nijmegen Medical Centre, the Netherlands.
Estimated mean Disease Activity Scores in 28 joints (DAS28) decreased from 4.3 to 3.2 from 1989 to 2008. The decline in estimated scores was fairly steady over time, and began before the start of the biologic era. A similar trend was seen with functional disability scores, which started at 0.65, and ended at 0.5, with the decreases beginning before the start of the biologic era.
Mean joint damage (Ratingen) scores decreased from 90% in 1989 to 50% in 2005, the last year that data were available for this measure, Dr. Kievit noted. Mean joint damage scores were much lower in the more recent years of follow-up.
She and her colleagues also looked at the number of orthopedic surgeries in the cohort over time. There were 13 surgeries in 197 patients in 1991 (incidence rate 0.07) and 14 in 728 patients in 2008 (incidence rate 0.02).
Patients in the cohort were from two centers in the Netherlands. Patients with newly diagnosed RA were entered into the cohort each year, for a total of 992 patients representing 8419 patient years of follow-up.
Rheumatoid factor and gender did not differ by year, and mean age increased from 56 years in 1989 to 61 years in 2008. Mean disease duration increased from 1.9 to 8.1 years across the study period.
Outcomes were compared by cohort year, and data were adjusted for differences in patient characteristics.
While secular trends, improvements in lifestyle (such as quitting tobacco use), or earlier referrals for specialty care later in the study period could provide an explanation for the improvements in RA control over time, the "most straightforward explanation is the introduction of biologics and tight control strategies, but also enhanced use of methotrexate and other DMARDs already available since the 1980s," Dr. Kievit said.
Neither Dr. Kievit nor any of her coauthors had any financial disclosures related to the presentation of these findings.