Limitations
There are various limitations to this study. It was a retrospective, single-center study and the patient population was relatively homogenous, with only 1 female and a mean age of 71 years. As a study conducted in a veteran population in West Virginia, the findings may not be representative of the general population with COPD, which includes more women and more racial diversity.9 The American Lung Association discusses how environmental exposures to hazardous conditions increase the risks of pulmonary diseases for veterans.10 It has been reported that the prevalence of COPD is higher among veterans compared to the general population, but it is not different in terms of disease manifestation.10
Another limitation is the short time frame. Clinical guidelines, including the GOLD Report, typically track the number of exacerbations for 1 year to escalate therapy.3 Six months was a relatively short time frame, and it is possible that more exacerbations may have occurred beyond the study time frame. Ten patients in the sample died between the end of the study period and data retrieval, which might have been caught by a longer study period. An additional limitation was the inability to measure adherence. As this was a formulary conversion, many patients had been mailed a 30- or 90-day prescription of the budesonide/formoterol inhaler when transitioned to the fluticasone/salmeterol inhaler. There was no way to accurately determine when the patient made the switch to the fluticasone/salmeterol inhaler. This study also had a small sample group (a pre-post analysis of the same group), a limitation when evaluating the impact of this formulary change on a small percentage of the population transitioned.
This formulary conversion occurred during the COVID-19 pandemic, and some exacerbations could have been the result of a misdiagnosed COVID-19 infection. Respiratory infections, including COVID-19, are common causes of exacerbations. It is also possible that some patients elected not to receive medical care for symptoms of an exacerbation during the pandemic.11
Conclusions
Switching from the budesonide/formoterol inhaler to the fluticasone/salmeterol inhaler through formulary conversion did not have a significant impact on the clinical outcomes in patients with COPD. This study found that although the inhalers contain different active ingredients, products within the same therapeutic class yielded nonsignificant changes. When conducting formulary conversions, intolerances and treatment failures should be expected when switching from different inhaler delivery systems. This study further justifies the ability to be cost effective by making formulary conversions within the same therapeutic class within a veterans population.
Acknowledgments
The authors would like to acknowledge James Brown, PharmD, PhD.