medwireNews: Older people with late-onset rheumatoid arthritis (RA) show a similar response to biologic or targeted synthetic DMARDs to their peers whose disease onset was earlier in life, Japanese study findings indicate.
Treatment response trajectories in CDAI were also comparable between people with and without a late disease onset, and age at diagnosis did not impact treatment discontinuation rates, report Yoshiya Tanaka and colleagues from the University of Occupational and Environmental Health in Kitakyshu City.
The researchers used registry data to explore the efficacy of biologic and targeted synthetic DMARDs in 1750 people with RA. Of these, 1040 developed the disease at or after 60 years of age and 710 were diagnosed earlier.
At baseline, 59.9% of people with late-onset RA and 56.3% of those with earlier-onset RA were biologic or targeted synthetic DMARD-naïve, and the proportions receiving each drug type, as well as methotrexate, were comparable across the two groups.
Tanaka and team found that a numerically greater proportion of people with late-onset RA had high disease activity (CDAI >22.0) at baseline, at 61.0% versus 54.1% of those with earlier-onset disease.
In spite of this, the proportions with high disease activity after 2, 22, and 54 weeks of treatment were similar between the two groups, at approximately 20%, 5%, and 2%, respectively.
For low disease activity (CDAI ≤10.0), the rates were 6.7% in the late-onset group and 7.3% in the earlier onset group at baseline, and approximately 41% and 78% in both groups at weeks 2 and 22, respectively. At week 54, the rate was numerically higher in the people with late-onset RA than in those with earlier-onset RA, at approximately 82% versus 79%.
After adjustment for potential confounders, the researchers observed no significant association between age at RA onset and CDAI.
Using trajectory analyses, the investigators identified three treatment response patterns among the participants, namely rapid, slow, and no response. They found that the proportions of patients in each response category was comparable between the late-onset and earlier-onset RA groups, at around 82–83%, 7–9%, and 10%, respectively.
During the study period, 41.9% of participants with late-onset RA and 38.9% of those with earlier-onset RA discontinued treatment.
Tanaka et al found that people with late-onset disease were no more likely than those with earlier-onset disease to discontinue due to lack of efficacy, infectious disease, or serious adverse events, after adjustment for potential confounders.
The authors note in The Journal of Rheumatology that previous studies have shown that older people with late-onset RA are more resistant to conventional treatments than similar aged people with earlier disease onset.
However, they believe their results suggest that late-onset RA may not be that different from earlier-onset RA when considering biologic and targeted synthetic DMARD responsiveness in older patients.
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