Burden of illness in blood eosinophilic phenotype COPD patients in New Zealand.

BACKGROUND

Real-world data on eosinophilic chronic obstructive pulmonary disease (COPD)'s clinical burden, in exacerbating/stable states, and the stability of blood eosinophil count (BEC) measurements are limited. We described measured BEC distributions among general practice COPD patients in New Zealand (NZ).

METHODS

This retrospective cohort study utilized the NZ-HealthStat primary care database. Participants were aged ≥40 years, with ≥1 BEC 6 months following a COPD diagnosis code during 2011-2012. Descriptive analyses included examinations of BEC stability and association with COPD exacerbations/treatments/comorbidities.

RESULTS

The most frequent COPD comorbidity was asthma (n = 1180/2909, 40.56%). Among COPD patients: 65% had BECs >150 cells/μL; 35% had BECs >300 cells/μL (non-mutually exclusive threshold categories). Treatment patterns were similar, except for more frequent inhaled corticosteroid (ICS)/long-acting beta-agonist use in COPD patients with asthma history (51%) than those without (31%). Factors associated with BECs >150 cells/μL in participants without ICS treatment included Māori/Pacific ethnicity, obesity, oral corticosteroid (OCS) use, and exacerbation history. When stratified by asthma history, ICS treatment, and neutrophil count above/below 5000 cells/μL, geometric mean BECs ranged from 136.70 to 398.52 cells/μL. Exploratory analyses showed a fair-good COPD/BEC measurement stability over 12 months.

CONCLUSIONS

Asthma was a common COPD comorbidity in NZ, particularly in Māori/Pacific patients. No overall relationship was observed between BEC/COPD exacerbations, which may reflect background ICS confounding. However, analyses in non-ICS treated participants suggested that Māori/Pacific patients with obesity and COPD, OCS treatment, exacerbation history, and/or elevated BECs are at the highest risk of COPD exacerbations. One BEC measurement appears a good indicator of a patient's BECs over time.