Cumulative dispensing of high oral corticosteroid doses for treating asthma in Australia

Objective To estimate the level of dispensing of oral corticosteroids (OCS) for managing asthma in Australia, with a particular focus on the cumulative dispensing of doses associated with long term toxicity (>= 1000 mg prednisolone-equivalent). Design Retrospective cohort study; analysis of 10% random sample of Pharmaceutical Benefits Scheme (PBS) dispensing data. Participants, setting People aged 12 years or more treated for asthma during 2014-2018, according to dispensing of controller inhaled corticosteroids (ICS). Main outcome measures Number of people dispensedOCSfor managing asthma during 2014-2018; proportion who were cumulatively dispensed at least 1000 mg prednisolone-equivalent. The secondary outcome was the number of people dispensed at least 1000 mg prednisolone-equivalent during 2018, stratified by inhaler controller dose and use. Results 124 011 people had been dispensed at least two prescriptions ofICSduring 2014-2018 and met the study definition for asthma, of whom 64 112 (51.7%) had also been dispensedOCS, including 34 580 (27.9% of the asthma group) cumulatively dispensed 1000 mg prednisolone-equivalent or more. Of 138 073 people dispensedOCSat this level, 68 077 (49%) were patients with airway diseases. Dispensing of diabetes and osteoporosis medications was more common for people cumulatively dispensed 1000 mg prednisolone-equivalent or more. During 2018, 4633 people with asthma using high doseICScontrollers were dispensed 1000 mg prednisolone-equivalent or more, for 2316 of whom (50%) controller use was inadequate. Conclusions Cumulative exposure toOCSin Australia reaches levels associated with toxicity in one-quarter of patients with asthma usingICS. Cumulative dispensing of potentially toxicOCSamounts often accompanies inadequate inhaler controller dispensing. Better approaches are needed to improve adherence to controller therapy, improve outcomes for people with asthma, and to minimise the use and toxicity ofOCS.