Investigating effectiveness of adherence of long-acting bronchodilator in chronic obstructive pulmonary disease with influenza infection

Abstract

Objectives: Long-acting bronchodilators are important treatments for chronic obstructive pulmonary disease (COPD) and adequate medication adherence decreases COPD exacerbations, especially in reducing the hazard of influenza infection. Therefore, the study aim was to evaluate adherence of long-acting bronchodilator treatment and the risk of influenza in patients with COPD. Methods: This retrospective nested case-control study included patients with newly diagnosed COPD from 2012 to 2018. Cases with influenza infection were defined and matched to 2 randomly selected controls. The influenza infection date was the index date. Conditional logistic regressions were used to estimate odds ratios of influenza from proportion of days covered (PDC) of long-acting bronchodilators measured in one year before the index date. Adherence was divided into high adherence (PDC ≥80 %) and low adherence (PDC <80 %). Results: This population-based study included 6,073 patients in the case group and 12,146 in the control group. High PDC of long-acting bronchodilators in COPD was associated with a 0.811-fold (95 % confidence interval: 0.754–0.883, P < 0.001) decreased influenza risk, where 906 (14.92 %) high PDC in case and 2,130 (17.54 %) in control. Low PDC without influenza vaccination in COPD patients is associated with increased influenza risk, regardless of exposure period. Conclusion: In Taiwan, COPD patients with high PDC were associate with lower COPD exacerbation. Different long-acting bronchodilator exposure or dose need to be further investigated in COPD patients.

Keywords

• Chronic obstructive pulmonary disease
• Influenza
• Adherence