Results of a study published in Rheumatology confirm American College of Rheumatology/European League Against Rheumatism guidelines indicating that remission is preferable to low disease activity in patients with early rheumatoid arthritis (RA).
Researchers sought to examine the associations between function, quality of life, and structural outcomes in patients with early RA who achieve remission vs those who achieve low disease activity. Data were pulled from 2 large inception cohorts from the United Kingdom: the Early Rheumatoid Arthritis Study (ERAS), a multicenter cohort of 1465 patients with early RA recruited between 1986 and 1999, and the Early Rheumatoid Arthritis Network (ERAN), a multicenter cohort of 1236 patients with early RA recruited between 2002 and 2012.
Investigators calculated disease activity based on the original Disease Activity Score and the more recent Disease Activity Score in 28 Joints (DAS28), then categorized disease activity by the mean score for years 1 through 5 and sustained scores in years 1 and 2. Remission was defined as DAS28 <2.6, and low disease activity was defined as DAS28 2.6 through 3.2. From this data, the following patient groups were created: mean low disease activity years 1 to 5 (mLDAS), mean remission years 1 to 5 (mRDAS), sustained low disease activity years 1 and 2 (sLDAS), sustained remission years 1 and 2 (sRDAS), and sustained Boolean remission years 1 and 2 (sBR).
In total, 2701 patients were included in the analysis. Investigators found that for all outcomes, differences in mean scores between the mRDAS and mLDAS groups at each time point during years 1 through 5 were “highly statistically different and increasingly divergent” in favor of mRDAS with each successive year. After controlling for baseline covariates, including erythrocyte sedimentation rate, body mass index, pain, comorbidities, social deprivation, DAS28, and smoking, the effects comparing mLDAS with mRDAS remained significant. Repeat analyses after variable restriction resulted in similar outcomes.
In comparing the sRDAS and sLDAS groups, total scores for all measures were “increasingly divergent” with successive years, favoring sRDAS. When comparing the outcomes between the sBR and sLDAS groups, scores were all “highly statistically significantly better” in the sBR group from year 1 and on and increasingly divergent with each successive year. Group differences in terms of MICD outcomes exceeded all thresholds.
One study limitation is that patients did not consistently achieve the DAS outcome of the group they were assigned to, which reflects real-world variations in disease activity that are “characteristic of RA.”
“We have shown highly significant and clinically meaningful associations between improved functional, quality of life, and structural outcomes in [patients with early RA] achieving remission compared with low disease activity … in the ERAS/ERAN real-world inception cohorts,” the researchers concluded. “These findings support [American College of Rheumatology] and [European League Against Rheumatism] guidelines that in early RA the primary goal should be remission.”
Nikiphorou E, Norton SJ, Carpenter L, et al; for ERAS and ERAN. Remission vs low disease activity: function, quality of life and structural outcomes in the Early Rheumatoid Arthritis Study and Network [published online October 3, 2019]. Rheumatology. doi: 10.1093/rheumatology/kez461