Risk factors for Staphylococcus aureus bacteremia in patients with rheumatoid arthritis and incidence compared with the general population: protocol for a Danish nationwide observational cohort study. - Dieperink SS; Glintborg B; Oestergaard LB; Nørgaard M; Benfield T; Mehnert F; Petersen A; Hetland ML (BMJ open, 2019)