Suissa S, et al. - Experts compared the efficacy and safety of long-acting β 2 agonists (LABAs) dispensed in fixed combination with inhaled corticosteroids (LABA-ICS) to long-acting muscarinic antagonists (LAMAs) treatment initiation in chronic obstructive pulmonary disease (COPD) targeted by blood eosinophils. According to findings, LABA-ICS treatment was only more effective than LAMAs in patients with high blood eosinophil concentrations (> 4%) or counts (> 300 cells per μL) and possibly in frequent exacerbators. In patients with blood eosinophil concentrations < 4%, the authors indicated that initiation with a LAMA should be preferred due to the increased risk of pneumonia associated with the ICS component.

Methods

• Researchers conducted this population-based cohort study to identify a cohort of patients with COPD initiating treatment with a LAMA or LABA-ICS during 2002-2015, aged ≥ 55 years, from the UK's Clinical Practice Research Datalink.
• Patients who initiated treatment with both bronchodilators on the same date were excluded.
• At least 1 year of medical history and a measure of blood eosinophil concentration before cohort entry, defined by the date of the first cohort-defining bronchodilator prescription, was required for all patients.
• The investigators matched patients initiating a LAMA on high-dimensional propensity scores with patients initiating a LABA-ICS.
• They followed them up for 1 year for the occurrence of a moderate or severe COPD exacerbation and for severe pneumonia.
• Among others, sensitivity analyses included repeating the analysis among patients with two blood eosinophil concentration measures and stratification by concurrent asthma and previous exacerbations.

Results

• A total of 5,39,643 patients with a prescription for LABAs or LAMAs were included in the base cohort, of whom 18,500 were initiated on LABA-ICS and 13,870 on LAMAs.
• Propensity score analysis resulted in 12,366 initiators of LAMAs (mainly tiotropium) matched to 12 366 initiators of LABA-ICS.
• They noted 0.95 to be the hazard ratio (HR) of COPD exacerbation associated with LABA-ICS initiation, relative to LAMA initiation.
• The HR was 1.03 in patients with blood eosinophil concentrations < 2% of white blood cell count; for those with eosinophil concentrations of 2% to 4%, the HR was 1.00.
• The HR for patients with eosinophil concentrations of > 4% was 0.79.
• According to results, there was an increase in the incidence of pneumonia with LABA-ICS initiation, which was similar across all eosinophil concentrations.
• Sensitivity analyses were consistent with findings; however, there was a marginally lower incidence of exacerbation with LABA-ICS among the 2,766 of all 24,732 patients with ≥ 2 COPD exacerbations during the baseline year.