Early recognition improves prognosis in elderly onset RA.

Although commonly diagnosed in the third to fifth decades of life, the incidence and prevalence of RA continue to increase up to the ninth decade. Age at onset is particularly relevant as the presentation may differ in elderly onset RA (EORA) compared with young onset RA (YORA). Patients with EORA frequently report a more acute presentation, especially if positive for rheumatoid factor (RF). Fever, fatigue and weight loss appear to be more common in EORA. Although small joints are most frequently involved in the RA population overall, there is common involvement of large joints in EORA and these proximal symptoms may mimic polymyalgia rheumatica (PMR). In YORA, approximately 80% of patients are seropositive for RF however a lower frequency has been reported in EORA. Anti-CCP antibodies have been detected in over 70% of patients with RA and are highly specific for RA. The value of anti-CCP antibodies is even higher in patients with an atypical presentation (e.g. PMR-like symptoms), or those who are RF negative. X-rays of the hands and feet should always be performed in patients with a suspected inflammatory arthritis. Baseline joint erosions are present in a similar proportion in patients with YORA and EORA. In the elderly, the differential diagnosis of RA is extensive as many conditions present in a similar way e.g. PMR, osteoarthritis, polyarticular gout, pseudogout and malignancy. Anti-CCP antibodies are very useful for identifying EORA patients with a polymyalgic onset. Ultrasonography or MRI can also be helpful in differentiating PMR from EORA.