Competing interests: We have read and understood the BMJ Group policy on declaration of interests and declare the following interests: GCM holds an Australian National Health and Medical Research Council (NHMRC) Early Career Fellowship (APP1141272). Flexeze provided heat wraps at no cost for the SHaPED trial that GCM is an investigator on. CAS is an academic fellow at the University of Sydney. Flexeze provided heat wraps at no cost for the HEAT pilot trial that CAS is lead investigator on. MU is chief investigator or co-investigator on multiple previous and current research grants from the UK NIHR, Arthritis Research UK, and is a co-investigator on grants funded by the Australian NHMRC. He is an NIHR senior investigator. He has received travel expenses for speaking at conferences from the professional organisations hosting the conferences. He is a director and shareholder of Clinvivo, which provides electronic data collection for health services research. He is part of an academic partnership with Serco related to return to work initiatives. He is a co-investigator on two NIHR funded studies that receive additional support from Stryker. He has accepted honoraria for teaching/lecturing from a consortium for advanced research training in Africa. Until March 2020 he was an editor of the NIHR journal series, and a member of the NIHR Journal Editors Group, for which he received a fee. ROD has been involved with consultancies for Reckitt Benkiser on advice on ibuprofen; all payments were made to an audited trust fund at St Vincent’s Hospital. Payment to ROD was made for expert testimony regarding a veterinary anti-arthritic product unrelated to NSAIDs.