Rheumatoid arthritis (RA) is a chronic inflammatory disease that predominantly affects middle-aged adults in the third to fifth decades of life, but can also occur at any age. Significant differences were observed between patients with the diagnose of the disease under the age of 65 years – young- onset of RA (YORA) and those with the onset over the age of 65 years -elderly-onset of RA (EORA). The literature has shown that patients in the EORA group, in comparison to the young, have more severe onset, shorter duration of morning stiffness, lower frequency of seropositivity and a more important biological inflammatory syndrome.
Objective: Describe and compare the clinical characteristics, laboratory features, functional status, therapeutic approach and disease progression in elderly-onset and young-onset rheumatoid arthritis (RA) patients.
Materials and Methods: This retrospective, transversal study included 102 patients diagnosed with rheumatoid arthritis according to the ACR / EULAR criteria and who had at least 3 visits to our clinic, the last one during 2019-2020. Depending on the age at disease onset, we divided them into 2 groups- EORA and YORA and analyzed them comparing the clinical, laboratory and treatment data obtained at diagnosis. Subsequently we studied the evolution of the disease activity and the therapy efficiency at 6 months of follow-up and at the last hospitalization for each group.
Results: The percentage of women is similar and predominant in both groups, YORA and EORA (68.3% and 71.8%). YORA was associated with a longer disease length and a prolonged symptom duration prior to the diagnosis in comparison to EORA (p<0.001 and P=0.002). Extra-articular manifestations were more frequent in elderly-onset RA patients at diagnosis, especially the presence of rheumatoid nodules (46.2% vs 22.2%. p=0.011) and weight loss (82.1% vs 34.9%, p<0.001). Anemia was statistically associated with the EORA group (p=0.037). Analyzing the radiological findings, there was a greater number of patients who showed erosions (48.7%) and geodes (28.2%) in EORA, than in YORA group (33.3% and 19.0%). The prevalence of specific auto-antibodies positivity as anti-CCP was higher in YORA (76.2% vs 53.8%, p=0.019), as well as the positivity of Rheumatoid factor (RF) (84.1% vs 61.5%, p=0.010). The majority of patients began treatment with synthetic DMARD monotherapy, 54.0% of YORA and 64.1% of EORA. Methotrexate was the main drug administrated in both groups (61.5% in EORA and 54.0% in YORA, p-value= 0.602). Other medications, such as Sulfasalazine and Leflunomide, were less preferred in the two groups. Biologic therapy was preferred in younger patients than in those with RA at 65 years of age or over (69.8% vs 35.9%, p=0.001). Disease activity measured with DAS28(CRP) score was similar between the two groups at baseline, but significantly lower for YORA patients measured at the last hospitalization (p=0.020), treat to target (low disease activity and remission) being achieved in 53% of cases in the YORA group versus 23% of EORA patients (p=0.002).
Conclusions: The definite diagnosis of RA was delayed in YORA patients in comparison to EORA patients and the extra-articular manifestations of the disease were more frequently found in the EORA group. Seropositivity was statistically significantly associated with the YORA group. Anemia was predominant in patients with disease onset over 65 years old. Both groups underwent DMARDs therapy in the early stages of the disease, but biologic therapy was more often administered in younger patients. Disease activity at diagnosis was similar in both groups, but in dynamic, the treat to target endpoint was achieved more frequent in YORA population.