ObjectiveWe aimed to describe the following in patients with polymyalgia rheumatica (PMR): (1) real-world glucocorticoid (GC) therapy, (2) improvement in inflammatory parameters associated with disease activity (C-reactive protein [CRP] level and erythrocyte sedimentation rate [ESR]), and (3) incidence of GC-related adverse events (AEs). MethodsA cohort study was conducted using a Japanese electronic medical records database. We included newly diagnosed PMR patients aged≥50years with baseline CRP levels≥10mg/L and/or ESR>30mm/h and an initial GC dose of≥5mg/day. The outcomes were GC dose, inflammatory parameters, and GC-related AEs. ResultsA total of 373 PMR patients (mean age, 77.3 years) were analyzed. The median initial GC dose was 15.0mg/day, which gradually decreased to 3.5mg/day by week 52. The median cumulative GC dose at week 52 was 2455.0mg. The median CRP level on day 0 was 64.3mg/L, which decreased during weeks 4–52 (1.4–3.2mg/L). At week 52, 39.0% of patients had a CRP level>3.0mg/L. The cumulative incidence of GC-related AEs at week 52 was 49.0% for osteoporosis, 30.2% for diabetes, 14.9% for hypertension, 12.2% for peptic ulcer, 11.3% for dyslipidemia, 2.9% for glaucoma, and 4.3% for serious infection. The incidence of osteoporosis and diabetes increased with the GC dose. ConclusionThe incidence of GC-related AEs was associated with the GC dose in PMR patients. Further research is required to identify treatment strategies that can effectively control PMR disease activity while minimizing GC use.