The incidence and clinical characteristics of peripheral arthritis in polymyalgia rheumatics and temporal arteritis: a prospective study of 231 cases

Objective. To evaluate the incidence and characteristics of peripheral arthritis in polymyalgia rheumatica and temporal arteritis, and to ascertain the incidence of rheumatoid arthritis among such cases. Patients and methods. In total, 231 patients were selected from a prospective population-based study. All patients were clinically examined on several occasions and followed until cessation of therapy and permanent disease remission. Results. Of the 231 cases, 38.5% presented peripheral arthritis either at diagnosis or during the disease course. At diagnosis, peripheral arthritis was not observed among patients with temporal arteritis. Peripheral arthritis occurring during the disease course was more often polyarticular and needed additional treatment more frequently than joint inflammation presenting at diagnosis; Only one case had distal pitting oedema. Rheumatoid arthritis developed in 4.8% of the cases and exclusively among patients with polymyalgia rheumatica. Conclusion. Aetiopathogenic differences may exist between polymyalgia rheumatica and temporal arteritis as peripheral arthritis and the development of rheumatoid arthritis were observed among the former patient group only.