The Effectiveness Of Immunotherapy For Allergic Asthma Among Different Weight Categories

Patients with obesity have been shown to have a more severe asthma phenotype compared to their normal BMI counterparts. Subcutaneous immunotherapy (SCIT) has been used as a treatment for allergic asthma, but it is unclear if overweight and obese patients have the same outcomes as normal weight patients. A retrospective chart review was done for 176 patients in the practice undergoing SCIT, with forty-three patients qualifying for inclusion. Inclusion criteria included age 5 to 70 years, diagnosis of allergic asthma, and comparable one-year data of asthma outcomes. Asthma outcomes included changes in asthma control test (ACT) score, spirometry parameters, and inhaled corticosteroid (ICS) dosage. Weight was categorized as either underweight/normal (NW) or overweight/obese (OW). The mean age of subjects was 22 years old, with forty-four percent of individuals in the OW category. FEV1/FVC was significantly improved in the NW group compared to the OW (delta 3 vs -1.5, p<0.0185) with FEV1 and PEF showing no significant relationship. No association was found between change in ICS dosage and weight category. ACT comparisons were unable to be done secondary to limited data. This is the first study to examine differential effects of SCIT based on weight status. The findings suggest that OW patients have decreased improvement in asthma parameters, as demonstrated by a decrease in their FEV1/FVC, compared to NW individuals. To elucidate other differences, future prospective studies with a larger sample size should be considered. Additionally, SCIT dosage adjustment should be studied in OW patients.