An observational study to characterize severe eosinophilic asthma in New Zealand

Abstract

Background: Patients with severe eosinophilic asthma (SEA) remain poorly described. Aim and objectives: This study aimed to characterize the epidemiology, medication use and healthcare resource utilization (HRU) of SEA patients compared to non-SEA asthma patients in New Zealand (NZ). Methods: A retrospective case-only cohort study was conducted to investigate adults (age 18+) enrolled in the HealthStat primary care database in NZ. Asthma patients were identified using diagnostic codes and prescriptions for inhaled corticosteroids (ICS). SEA was defined using the following criteria during a 1-year baseline period (2011): ICS prescription above the medium dose plus a controller medication, 2+ exacerbations, and an eosinophil cell count ≥300 cells/µL (or ≥150 in 6 weeks prior to index). SEA and non-SEA patients identified during baseline were followed for 1-year (2012) to evaluate HRU and related costs. Results: Among 3737 asthma patients, 6.2% (n=230) met the criteria for SEA. SEA prevalence was highest for individuals with Maori ethnicity (9.4%), age 60-69 years (9.3%), and former smokers (8.0%). Compared to the non-SEA group, SEA patients were more likely to have diabetes (23% v 15%) or heart failure (10% vs 5%) and a higher mean for BMI (33 vs 31 kg/m2) and neutrophil counts (5.2 vs 4.6 109/L). During baseline, SEA patients had six times as many exacerbations and twice as many respiratory treatment prescriptions than the non-SEA group. SEA patients had 70% more HRU and 3.4 times higher annual HRU costs compared to non-SEA patients. Conclusions: SEA patients had more comorbidities and medication usage and higher HRU and associated costs compared to non-SEA asthma patients in NZ. Funding: GSK (208970)