medwireNews: Among patients with rheumatoid arthritis (RA), a combination of anticitrullinated protein antibody (ACPA) and rheumatoid factor (RF) positivity is associated with faster treatment response and a greater likelihood of achieving remission, researchers report.
Using data from 970 patients treated with antirheumatic medications who were included in the Ontario Best Practices Research Initiative registry between 2008 and 2017, Janet Pope (University of Western Ontario, London, Canada) and study co-authors demonstrated that patients who were positive for both ACPA and RF were significantly more likely to achieve sustained remission (CDAI score ≤2.8 at two or more sequential visits separated by 3–12 months) than those who were negative for both autoantibodies.
Specifically, rates of sustained remission over an average follow-up of 3 years were 43.5% for the 531 patients positive for both autoantibodies, and 32.4% for the 262 who were ACPA- and RF-negative, translating into a 30% higher likelihood of sustained remission among the positive group after adjustment for age, sex, and baseline disease activity. Patients in the former group also experienced a significantly greater improvement in CDAI score over the follow-up period.
And the median time to achieving first sustained remission was significantly shorter among ACPA- and RF-positive patients compared with their autoantibody-negative counterparts, at 3.7 versus 5.1 years, report the researchers in RMD Open.
“Combined ACPA and RF positivity were associated with improved and faster response to antirheumatic medications in patients with RA,” summarize Pope and team.
They note, however, that this “seems to be driven by ACPA status rather than RF status as a similar strong association was found between positive ACPA and low disease activity compared with negative ACPA.”
Indeed, 43.3% of the 60 patients who were positive for ACPA but negative for RF achieved sustained remission over the follow-up period, compared with 32.4% of those with dual negativity and 31.6% of the 117 patients negative for ACPA but positive for RF.
The study authors caution that their study was not able to assess the relationship between ACPA/RF status and structural joint damage because radiographic data were not collected in the registry, and that unmeasured confounders may have influenced the results.
Nonetheless, they believe that their findings are “particularly relevant […] for rheumatologists seeing patients in routine clinical care and could inform decision-making in the management of patients with RA.”
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