Potentially inappropriate prescribing of DOACs to people with mechanical heart valves: A federated analysis of 57.9 million patients' primary care records in situ using OpenSAFELY. Issue 211 (March 2022) - Fisher, Louis; Speed, Victoria; Curtis, Helen J.; Rentsch, Christopher T.; Wong, Angel Y.S.; Schultze, Anna; Massey, Jon; Inglesby, Peter; Morton, Caroline E.; Wood, Marion; Walker, Alex J.; Morley, Jessica; et al.