Although the risk is small, medium- and high-dose ICS are associated with serious adverse events.

Inhaled corticosteroids (ICS) are the backbone of asthma therapy, but higher doses have been associated with adverse effects such as thrush, dysphonia, pneumonia and decreased bone mineralisation. Although 80 to 90% of the maximum benefit of ICS can be obtained with low doses, many patients are placed on high doses with little consideration of adverse effects.

Researchers used UK databases to study 160,000 adults with asthma, including 96,000 who initiated ICS. One year of ICS use at medium or high doses was associated with significant excess risk for major adverse cardiac events (hazard ratios, 2.6 for medium doses and 4.6 for high doses), arrhythmia (2.2 and 2.9), pulmonary embolus (2.1 and 3.3) and pneumonia (2.3 and 4.1). No excess risk was seen with low-dose ICS. Absolute event numbers were small, and numbers needed to harm (NNH) were 220 to 570 for most outcomes (pneumonia had an NNH of 93 for patients taking high-dose ICS for one year).

Comment: Although serious adverse events are not common with ICS, this study reminds us that these medications are not without risk. Before escalating to high-dose ICS, we should make sure patients truly have asthma, ensure they are using their inhalers correctly, address their comorbidities and consider referral to an asthma specialist. Once asthma is well controlled for three months, we should step down the ICS dose. Finally, to lower ICS exposure, we should use low-dose ICS/formoterol for maintenance and reliever therapy and consider use of asthma biologics in those with frequent exacerbations and type 2 (eosinophilic) inflammation.

Avid J. Amrol, MD, Associate Professor of Clinical Internal Medicine, Director of the Division of Allergy and Immunology, University of South Carolina School of Medicine, Columbia, USA.

Bloom CI, et al. Association of dose of inhaled corticosteroids and frequency of adverse events. Am J Respir Crit Care Med 2024; 211: 54-63.

This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine, Hospital Medicine.