High Relapse Rate in Patients with Polymyalgia Rheumatica despite the Combination of Immunosuppressants and Prednisolone: A Single Center Experience of 89 patients

Polymyalgia rheumatica (PMR) is an inflammatory disorder in the elderly and is characterized by pain in the shoulders and lower back. Previous studies from western countries have shown that relapse is frequent; however, there are only a few reports on the relapse rate in Japan. Here we examined the relapse rate, and sought to identify factors that predict recurrence in patients with PMR. Of 110 patients who fulfilled the Bird's criteria for PMR between May 2011 and June 2019, 21 patients were excluded, and the remaining 89 patients were followed up until July 2019. Relapse was defined when clinical symptoms were exacerbated and serum C-reactive protein level increased. The relapse-free survival curves were plotted using the Kaplan-Meier method, and log-rank test was used for statistical analysis. The mean age of the 89 patients (50 males and 39 females) was 71.8 years. The mean dose of initial prednisolone (PSL) was 11.8 mg/day. The 1-, 3-, and 5-year relapse-free survival rates were 81.6%, 58.0%, and 52.3% (N = 59, 21, and 7), respectively. In patients who experienced recurrence, the 1- and 3-year second relapse-free survival rates were 58.3% and 27.3% (N = 18 and 3), respectively. Immunosuppressants, such as methotrexate and tacrolimus, were added to PSL in 19 of 30 patients who experienced relapse at the discretion of the attending physicians; however, none of the immunosuppressants worked for preventing second relapses and had steroid-sparing effects. These results indicate that effective immunosuppressants are required to suppress relapse in the treatment of PMR.