medwireNews: Symmetrical- and small-joint pain may be associated with an increased risk for developing rheumatoid arthritis (RA) among family members of those with the condition, suggest findings from the PREVeNT-RA study.
“Given the genetic predisposition to RA, first-degree relatives (FDRs) of people with RA are a group at higher risk of developing the disease, with a 2–4 times higher risk compared to the general population,” explain Ian Bruce (The University of Manchester, UK) and co-researchers.
To determine potential predictors of future RA risk in these people, the PREVeNT-RA investigators evaluated questionnaire results and blood samples from 870 individuals aged 30 years and older who were FDRs (parents, children, siblings, or half-siblings) of someone with a diagnosis of RA. The average age of the participants was 51.8 years and 76.6% were women.
Bruce and team report in Arthritis Research & Therapy that 17.9% of the overall cohort reported having joint pain symptoms, most commonly in the large joints (31.0%) followed by small joints (22.8%) and symmetrical joints (17.1%).
Participants were then categorized according to whether or not they were at higher risk for future RA development based on seropositivity and inflammation. A total of 5% were seropositive for rheumatoid factor or anticitrullinated protein antibodies, while 14% had elevated C-reactive protein (CRP) levels (≥5 mg/L), indicative of inflammation.
People with elevated CRP levels had significantly higher rates of pain in symmetrical (27.0 vs 15.5%) and small (32.0 vs 21.3%) joints than those without. Seropositive individuals also had numerically higher rates of both symmetrical- and small-joint pain than seronegative participants, but the between-group differences did not reach statistical significance.
Based on these findings, “having both symmetrical and small joint pain was considered suggestive of RA and therefore was incorporated as an alternative outcome measure to seropositivity,” say the researchers.
They then used a multivariate logistic regression model to identify predictors of both types of joint pain, finding that older age, depression, and seropositivity were significantly associated with an increased risk, whereas leaving education at age 18–20 years was associated with a significantly reduced risk relative to leaving at 16–17 years.
The team notes that the PREVeNT-RA study had a number of limitations, including an insufficient number of people developing incident RA to validate the questionnaire results “against the outcome of a clinical RA diagnosis.”
While seropositivity was used “as a proxy measure of this outcome,” Bruce et al acknowledge “that not all patients with RA are seropositive nor [do] all seropositive individuals develop RA.”
They also investigated non-joint-related symptoms in the PREVeNT-RA cohort, but found that these symptoms “did not show a clear pattern helpful for identifying patients at risk of RA.”
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