High-dose corticosteroids associated with atrial fibrillation in the elderly

High-dose corticosteroid therapy (7.5 mg/day prednisone or equivalent) increases the risk of atrial fibrillation (AF) six-fold in older patients, a new epidemiological study has shown.The conclusion was based on data from the Rotterdam study, a long-term observational cohort study of people living in the community who were 55 or older when enrolled in 1990. There were 385 participants, with an average age of 73, who developed new-onset AF during ten years of observation. They were compared with all other participants, numbering about 6,400, without AF. Overall, receiving corticosteroids in the month prior to the diagnosis of AF significantly increased the risk of the arrhythmia by a factor of 3.75. The association was stronger and highly significant for high-dose therapy of at least 7.5 mg/day prednisone, with an odds ratio of 6.07, but it was smaller and non-significant for lower doses.Elevated risk of AF occurred regardless of the indication for corticosteroids, whether for asthma/COPD (13 cases) or a range of other conditions including polymyalgia rheumatica, rheumatoid arthritis, allergic skin reactions and multiple myeloma (16 cases).Older patients taking high-dose corticosteroids required careful monitoring by clinical examination and ECG, the report stated. It would increase the opportunity to diagnose and treat AF early and reduce the likelihood of serious consequences such as heart failure, stroke and the entrenchment of chronic AF.Several mechanisms could account for the association. Corticosteroids affected the passage of potassium across cell membranes, and their mineralocorticoid effects such as sodium and fluid retention could contribute to hypertension, left atrial enlargement and congestive heart failure. The medication probably acted as a trigger in patients with underlying cardiovascular risk factors, rather than as a single cause.There had been single case reports and case series describing possible links between corticosteroid treatment and AF, but this was thought to be the first rigorous epidemiological evaluation of the issue. Reference...