Therapeutic response to prednisone in relation to age in polymyalgia rheumatica: a comparison study

The aim of this study was to evaluate the impact of age on the therapeutic response to prednisone. This was a retrospective, monocentric study. We included patients diagnosed with PMR, according to ACR 2012 criteria. Patients were classified into two groups according to age (above or below 60 years old). We registered demographic, clinical, biological, imaging data, and therapeutic response profile. Local inflammation was evaluated at baseline with PET/CT imaging score. The treatment was standardised. The main endpoint was a corticosteroid dependence defined by the recurrence of PMR symptoms and/or the increase of CRP at two times. We included 14 patients younger than 60 years old (mean age 54 ± 0.8) and 28 patients older than 60 (mean age 75.8 ± 1.5). The "young PMR" group was mainly male (60 vs 27%; p < 0.05). Both groups were similar regarding morning stiffness, disease duration, WBC count, and CRP. The intensity of FDG uptake was lower (score of 16.9 ± 1.7 vs 26.5 ± 3.0; p < 0.05), there were more dependence on corticosteroids (60 vs 20%; p < 0.05) and methotrexate was more necessary (35 vs 6.5%; p < 0.05) in "young PMR" group. Young patients diagnosed with PMR are mostly men, are more dependent on corticosteroids, and have a lower PET-CT score at baseline in comparison to elderly patients diagnosed with PMR.