Researchers at the University of Pittsburgh have shown decreased levels of perceived pain may cause underestimation of disease activity in older patients with rheumatoid arthritis compared with younger patients.
Investigators categorized 740 patients with rheumatoid arthritis (RA) from the University of Pittsburgh Rheumatoid Arthritis Comparative Effectiveness Registry (RACER) into the following groups based on age: patients younger than 60 years and patients aged 60 years and older. The median patient age was 61.2 years and disease duration was 14.4 years. Investigators evaluated patients at baseline using a modified DAS28 incorporated with C-reactive protein (CRP) levels. They defined moderate inflammation as a modified DAS28 score above the 50th percentile, and this was present in 370 patients.
Multivariate analyses showed patient pain levels negatively correlated with age after researchers adjusted their findings for sex, race, comorbidities and inflammation. The 189 patients with moderate inflammation who were older than 60 years had lower levels of pain, tender joints, patient global assessment scores, physician global assessment scores, Routine Assessment of Patient Index Data 3 (RAPID3) scores and DAS28-CRP compared with younger patients, but older patients had a higher number of swollen joints. Physical health based on the SF-12 did not differ significantly between groups. Mental health scores were higher in the older group, while patients with disease activity beneath the 50th percentile had no differences based on age.
“Decreased pain level in older RA patients with a similar degree of joint inflammation as younger RA patients leads to underestimation of disease activity measured by either patient-reported outcome (RAPID3) or composite disease activity index (DAS28-CRP),” the researchers wrote. “This suggests that current clinical disease activity measurements may not fully reflect the severity of disease in older RA patients.” - by Shirley Pulawski
Hwang YG, et al. Paper #2643. Presented at: American College of Rheumatology Annual Meeting; Nov. 7-11, 2015; San Francisco.
Disclosures: The researchers report no relevant financial disclosures.