The Composite Asthma Severity Index: A Tool for Assessing Impact of Omalizumab Treatment in Children with Moderate-to-Severe Persistent Allergic Asthma
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Stanley J. Szefler, MD FAAAAI, Tmirah Haselkorn, PhD, Benjamin Ortiz, MD, Benjamin L. Trzaskoma, MS, Ahmar Iqbal, MD, William W. Busse, MD FAAAAI
RATIONALE: The Composite Asthma Severity Index (CASI) is a validated, multidimensional instrument for determining asthma severity using 5 domains: day symptoms and albuterol use, night symptoms and albuterol use, controller treatment, lung function, and exacerbations (Wildfire et al., JACI 2012). In this post hoc analysis from a randomized, controlled trial of omalizumab, CASI was examined as a tool for assessing impact of treatment intervention in children ≥6 to <12 years with moderate-to-severe persistent allergic asthma.

METHODS: Poisson regression analysis examined exacerbation rate reductions for omalizumab versus placebo at Week 24 stratified by median CASI score at baseline (≤7 (n=360) vs. >7 (n=216)). A higher CASI score indicates more severe asthma. Clinically significant exacerbations were defined as those requiring either systemic corticosteroid therapy or a doubling of baseline inhaled corticosteroid dose for ≥3 days.

RESULTS: Baseline age, sex, total IgE and eosinophil levels were similar between treatment groups and across CASI strata. The CASI>7 group had higher proportions of black children, males, lower mean percent predicted pre-bronchodilator FEV1, and greater maximum reversibility than the CASI≤7 group. Exacerbation rates were reduced by the following for omalizumab versus placebo: CASI≤7, 20% (-16%, 44%; p=0.24); CASI>7, 45% (18%, 63%; p=0.004).

CONCLUSIONS: CASI is a useful clinical tool to identify children who are likely to achieve favorable response to omalizumab. In children with greater asthma severity, as measured by a higher CASI score, a significantly greater response to omalizumab was observed for exacerbation reduction versus placebo; children with lower CASI scores had nonsignificant differences in reductions in exacerbation rates.