Baseline blood eosinophil counts may be used to identify a substantial proportion of patients hospitalized with asthma who could be treated with shorter steroid courses without evidence of early clinical deterioration.
In a randomized, controlled, open-label trial conducted in Singapore, researchers noted that an eosinophil-guided approach to systemic corticosteroid duration met prespecified noninferiority criteria and reduced cumulative steroid exposure in patients with noneosinophilic exacerbations. Treatment failure occurred in 11% (n = 6/55) of the patients assigned to eosinophil-guided care and 7% (n = 4/55) of those receiving usual care, corresponding to an absolute difference of 4%, which met the prespecified noninferiority margin. All treatment failures were attributable to the extension of systemic corticosteroid therapy, with no deaths or episodes requiring invasive or noninvasive mechanical ventilation reported.
The researchers enrolled 110 adult patients aged 21 years or older who were hospitalized for physician-diagnosed asthma exacerbation and hadn't received systemic corticosteroids within 7 days prior to presentation. The participants were randomly assigned 1:1 to undergo usual care or an eosinophil-guided strategy at two tertiary hospitals. Usual care consisted of 5 days of oral prednisolone for all patients. In the eosinophil-guided group, treatment duration was determined by baseline blood eosinophil count obtained prior to corticosteroid administration, with 3 days of prednisolone prescribed for counts below 300 cells/µL and 5 days for counts of 300 cells/µL or higher. Prednisolone dosing was weight based at 0.5 mg/kg per day and capped at 20 to 50 mg. Analyses were conducted according to the intention-to-treat principle.
The researchers stated that 60% of the participants had eosinophilic exacerbations and 40% were classified as noneosinophilic. There were no statistically significant differences in overall cumulative systemic corticosteroid exposure between the eosinophil-guided and usual care groups. However, within the eosinophil-guided group, patients who had noneosinophilic exacerbations received lower cumulative prednisolone-equivalent doses compared with those who had eosinophilic exacerbations, a difference not observed among patients treated with standard fixed-duration therapy.
Secondary outcomes were similar between the groups. Hospital length of stay, changes in Asthma Control Questionnaire-5 scores through 90 days, additional systemic corticosteroid bursts within 14 days, and time to recurrent exacerbation over 1 year didn't differ significantly. Rates of pneumonia and other corticosteroid-associated adverse events were low and comparable across the treatment groups.
The researchers identified several limitations. Open-label design may have introduced bias, particularly because treatment failure included clinician-directed extension of corticosteroid therapy. The prespecified noninferiority margin of 20% may be considered relatively broad. The study was conducted at two centers in Singapore, which may have limited generalizability, and the small number of treatment failure events limited subgroup analyses. In addition, lung function outcomes weren't systematically assessed. Larger, double-blind trials in more diverse populations are needed to confirm these findings and further define the role of eosinophil-guided corticosteroid duration in hospitalized asthma exacerbations.
Lead study author Anthony Yii, of the Department of Respiratory and Critical Care Medicine at Changi General Hospital in Singapore, and colleagues noted: “[U]sing the blood eosinophil count to determine the duration of systemic corticosteroid therapy was noninferior to usual care in preventing treatment failure, while reducing cumulative corticosteroid exposure for noneosinophilic patients.”
The authors reported no conflicts of interest.
Source: Thorax
