Potency of Inhaled Corticosteroid Fails to Predict Reduced Emergency Department Visits—Reply

In reply. Data presented by Dr Williams support our recent observation that low-dose inhaled corticosteroids are effective in preventing ED visits for asthma.¹ Although neither Dr Williams' study nor ours evaluated lung function or patient symptoms, a recently conducted meta-analysis from Holt and colleagues² indicates that 80% of maximum benefits on lung function and symptoms occur at fluticasone-equivalent doses of 200 µg/d or less.² Doses greater than 500 µg/d do not appear to add any additional therapeutic benefit for patients.² On the other hand, risks of important systemic adverse effects including bone demineralization and cataracts increase in a dose-dependent fashion.^3- 4 For these reasons, we agree with the NAEPP guidelines suggesting that clinicians use the "lowest possible dose of inhaled corticosteroid to maintain control" of asthma.⁵ Based on current evidence, for most patients, this can be achieved with total daily doses less than 500 µg of fluticasone (or equivalent).