Dr Massasso undertook Rheumatology advanced training at Royal North Shore, Liverpool and Royal Prince Alfred hospitals, between 2004-6.
- rheumatoid arthritis,
- psoriatic arthritis and spondyloarthritis,
- crystal-associated arthritis
- musculoskeletal medicine.
He has published widely in clinical research including in the areas of: septic arthritis, crystal-associated arthritis, SLE, vasculitis, nutritional disease, and osteoarthritis.
He is a long-standing member of the Australian Rheumatology Association, including as council member of the NSW branch (2011-2017) and as an examiner for the Royal Australasian College of Physicians.
Dr Massasso has considerable experience in junior doctor, registrar and medical student education in the role as Director of Prevocational Education and Training at Liverpool Hospital from 2007-2017 and as the Director of Clinical Training at Macquarie University Hospital (MQHealth) 2017 to present.
He has appointments as conjoint Lecturer with the University of NSW and conjoint senior lecturer with Macquarie University.
Dr David Massasso