Abstract
BACKGROUND: Late-onset rheumatoid arthritis (LORA) poses a great challenge for physicians regarding diagnosis and treatment. The prognosis for LORA was better in some early research but worse in more recent trials. OBJECTIVES: The study aim was to compare the clinical, laboratory, and radiological characteristics assessed by musculoskeletal ultrasound (MSUS) of patients with LORA and early-onset rheumatoid arthritis (EORA) and to examine their associations with inflammation and treatment outcomes. DESIGN: The study included 64 RA with EORA and 64 RA patients with LORA, fulfilling the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) 2010 criteria for RA. METHODS: Medical history, Health Assessment Questionnaire Disability Index (HAQ-DI), DAS 28 score, laboratory investigations, and MSUS of both hands and wrist joints were done. RESULTS: Female patients with EORA were more compared with those with LORA (89% vs 78.1%). Comorbidities were significantly more prevalent in the LORA group (28.12%) compared with the EORA group (10.9%) (P = .0143). A significant difference was also observed between the 2 groups regarding higher ESR values in LORA, with no significant difference detected in C-reactive protein (CRP) levels. Regarding joint involvement, shoulder, metatarsophalangeal (MTP), and knee joints were more frequently affected in LORA, with statistically significant differences (P < .0001, .0119, and .0285, respectively). The MSUS findings revealed higher gray-scale grades in patients with LORA, with significantly increased Doppler signal activity (P < .052), and a greater frequency of erosions compared with those with EORA. The mean HAQ-DI score was significantly higher in LORA than in EORA (P = .0004). Regarding treatment patterns, methotrexate (MTX) was more commonly prescribed in the EORA group (67.1%) compared with the LORA group (37.5%), whereas leflunomide was used more in LORA (68.75%) compared with EORA (46.8%), with statistically significant difference. CONCLUSIONS: Patients with LORA demonstrated more active synovitis and a higher frequency of erosions compared with those with EORA, despite the non-significant difference in DAS 28 scores. Moreover, patients with LORA exhibited a greater burden of comorbidities than those with EORA. Therefore, regular evaluation of inflammatory activity using MSUS, along with assessment of associated comorbid conditions, is recommended in patients with LORA.