Dejaco C, Duftner C, Wipfler-Freissmuth E, et al, Elderly- versus younger-onset rheumatoid arthritis: Higher levels of ultrasound-detected inflammation despite comparable clinical disease activity. Arthritis Care Res (2013) 65: 304–308
Elderly patients with late-onset rheumatoid arthritis (RA) have more inflammation in their joints than younger RA patients, even though their overall clinical disease activity (as measured by composite scores such as the Simplified Disease Activity Index or SDAI) does not appear different. This is the conclusion from the first study to compare ultrasonographic studies of patients with elderly-onset RA (EORA, onset at age 60 or above) and younger-onset RA (YORA) patients.
Elderly patients are more likely to present with acute onset of disease, note the research team from Austria, writing in Arthritis Care & Research, who found a shorter disease duration before diagnosis (2 months vs 26 months) in the older cohort of the retrospective analysis involving 145 patients. The study assessed 22 joints in both groups.
Among the 70 EORAs, with a median age of 71, more exhibited synovial hypertrophy/effusion than the 75 YORAs with a median age of 47. This was most prominent in the wrists (87%, vs 74.7% respectively) and the proximal interphalangeal joints (90% vs. 76%), while more of the younger patients displayed joint swelling in the wrists (46.9% vs. 34.3%) and in the metacarpophalangeals (51.6% vs. 35.2%). Equal numbers had joint tenderness. Around 40% in both groups used methotrexate as their primary DMARD.
The researchers said that a slightly higher prevalence of erosive disease in the younger patients could be explained by the longer disease duration in this group.
Limitations of the study included its retrospective design and missing clinical data for the two groups.
The authors note that disease activity in the elderly is often underestimated in clinical practice, although older people commonly present with severe illness, including arthritic and constitutional symptoms leading to transient or permanent immobility.
They suggest this may be due to the lack of sensitivity and specificity of clinical composite scores to detect joint inflammation (which may also be influenced by osteoarthritis and other noninflammatory joint pain common in the elderly), as compared to the reliability of ultrasound as seen in previous studies.