Real-World impact of nonclinical inhaler regimen switches on asthma or COPD: a systematic review

Background: Switching inhaler regimens can be driven by poor disease control but also by nonclinical factors, such as cost and environmental impact. The consequences of switching for nonclinical reasons are largely unclear.

Objective: To systematically review the real-world consequences of switching inhaler regimens for nonclinical reasons in asthma and/or chronic obstructive pulmonary disease patients.

Methods: Embase, MEDLINE, EBM Reviews, and EconLit were searched to November 21, 2020. Conference searches and reference checking were also performed. Real-world studies of asthma and/or chronic obstructive pulmonary disease patients undergoing a switch in inhaler regimen for any reason apart from clinical need were included. Two reviewers screened and extracted data. Key outcomes included symptom control, exacerbations, and patient-doctor relationships.

Results: A total of 8,958 records were screened and 21 studies included. Higher-quality (matched comparative) studies were prioritized. Five matched studies (6 datasets) reported on symptom control: 5 datasets (n = 7,530) with unclear patient consent reported improved disease control following switching, and 1 dataset (n = 1,648) with non-consented patients reported significantly worsened disease control. Three matched studies (5 datasets, n = 10,084) reported on exacerbation rate ratios; results were heterogeneous depending on the definition used. Two studies (n = 137) reported that switching inhaler regimens could have a negative impact on the doctor-patient relationship, especially when the switches were non-consented. Study quality was generally low.

Conclusions: Switching inhaler regimens is a complex issue that can have variable clinical consequences and can harm the patient-doctor relationship. Limited high-quality evidence was identified, and study designs were heterogeneous. A robust framework is needed to guide the personalized switching of inhalers.