For patients with asthma or chronic obstructive pulmonary disease (COPD) using an inhaler, switching their inhaler regimen with or without consent can lead to unpredictable, inconsistent results for the patient, according to systematic review findings presented at the American Thoracic Society (ATS) International Conference 2022 held in San Francisco, CA, May 13 to 18, 2022.

The decision to switch inhaler regimens may be motivated by clinical factors such as ineffectiveness or a bad reaction, or by nonclinical reasons such as financial or preference of use. Consequences of clinical switching are easily observable; however, consequences for nonclinical switching are not well-documented.

Researchers sought to examine real world evidence on the impact of switching inhalers for nonclinical reasons in patients with asthma and COPD through a retrospective systematic review. The review analyzed 21 studies from Embase, MEDLINE, EBM Reviews, and EconLit, as well as 11 conference presentations published through mid-November 2020 reporting on inhaler switching for asthma or COPD patients for any reason that did not include clinical necessity. Primary outcomes were categorized as: clinical, including symptom control, exacerbations, lung function, patient – health care provider relationship, satisfaction/preference, return to previous inhaler, adherence, incidence of hospitalization, change in rescue or reliever medication use; and cost/resource use, including direct costs, indirect costs, healthcare resource use, concomitant medication use, lost productivity, cost drivers. Investigators also looked at predictors of successful switching.

Continue Reading

Matched comparative studies were prioritized. In 5 of those (N=7530), although symptom control improved, results were ambiguous as to whether patients had agreed to the switch. In another matched comparative study (N=1648) with no ambiguity — ie, patients did not consent to switch — researchers found “significantly worsened disease control” after the switch was made. In 4 matched studies reporting on SABA reliever medication (N=7050), with ambiguous consent, average daily SABA usage dropped after switching. In 2 more matched studies (N=2574), where there was ambiguity about consent or clearly no consent, there was a significant or numerical increase in SABA use after switching.

Depending on how the statistics were reported, in 1 matched study (N=926) exacerbations significantly increased after switching; in 1 matched study (N=1958) exacerbations numerically increased; in 4 matched studies (N=6534) there was no difference in exacerbations; in 1 matched study (N=2568) exacerbations numerically decreased; and in 3 matched studies (N=8806) exacerbations significantly decreased after switching. These investigators were not happy with the quality of the studies they examined.

Researchers urge clinicians to steer clear of changing inhalers without a patient discussion. “Switching inhalers can have highly variable clinical consequences. Limited high-quality evidence suggests that inhaler switching without engaging the patient in the process should be avoided,” they concluded. The investigators also cited a need for further research to investigate and determine circumstances when switching may be warranted.

Study limitations included possible selection bias and no discussion on why clinicians would switch patient inhalers for nonclinical reasons without patient discussion.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for more information.


Usmani OS, Bosnic-Anticevich SZ, Dekhuijzen P, et al. Real world impact of nonclinical inhaler switching on asthma or COPD patients — a systematic review. Presented at: the American Thoracic Society (ATS) 2022 International Conference; May 13-18, 2022; San Francisco, CA. Abstract P718.