Background Treatment response in ERA reflects individual prognostic factors and therapeutic selection which may be influenced by provider experience and beliefs. This may lead to variations in rates of and time to remission across centres involved in multi-site cohorts.
Objectives We compared therapeutic strategies across Canadian ERA clinics in relation time to CDAI and DAS28 remission, and frequency of attaining sustained remission.
Methods Data were analyzed for patients with >1 year of follow-up, enrolled at sites with >40 patients at baseline and >30 patients with 2 years of follow-up data. We determined time to remission and frequency of sustained remission (2 consecutive visits at least 6 months apart), using DAS28 and CDAI scores. Treatment strategy was determined as initial and ever use of oral methotrexate monotherapy, subcutaneous methotrexate monotherapy, methotrexate-based combinations, non-methotrexate DMARDs, triple therapy, or biologic therapy.
Results 1,749 participants from 13 centers with mean age 54 years, 73% female, mean DAS28 4.9 (SD 1.4) and mean CDAI 25.6 (SD 14.6) were included. There were significant differences between centers in participant characteristics (gender, age, symptom duration, body mass index, comorbidities, smoking status, education, ethnicity, marital status, seropositive status, erosions). The initial therapeutic strategies were oral methotrexate monotherapy 16% (site range 0%>55%), subcutaneous methotrexate monotherapy 15% (0%>45%), methotrexate-based combination therapy 30% (10%>47%), non-methotrexate DMARDs 19% (4%>44%), triple therapy 11% (0%>60%), and biologics 2% (0%>18%). At 60 months of follow-up, the frequency of use of these strategies was relatively stable except for biologics which increased to 21% (0%>80%). The mean and median time to DAS28 remission was 12.4 months (SD 12.1, range 8.6 to 17.2) and 9 (IQR 3, 18) months respectively. The mean and median time to CDAI remission was 14.8 (SD 13.5, range 10.3 to 21.2) and 9 (IQR 6, 18) months respectively. The frequency of sustained DAS28 remission was 50% (site range 20–70%), and CDAI 35% (12–58%). At the two sites with the highest rates of sustained remission and shortest time to remission, patients had fewer comorbidities and the initial treatment strategy was preferentially methotrexate-based combination therapies, and with eventual advancement to biologics in 7 and 39% in patients. In contrast, the patients at the site with the lowest rates of sustained remission and longest time to remission had long symptom duration at treatment initiation, highest body mass index and proportion with ≥2 comorbidities, worse socioeconomic status and higher baseline DAS28. This site also had the highest proportion of patients treated with biologics at the baseline visit, escalating to 80% by 60 months.
Conclusions Treatment strategy and patient characteristics vary across CATCH sites and contribute to variable rate and frequency of achieving sustained remission.
Disclosure of Interest None declared