Limitations

The presence of a diagnosis code on a medical claim is not positive proof of disease, but may have been incorrectly coded or included as rule-out criteria. However, we required ≥2 diagnosis codes for COPD plus ≥1 claim for a long-acting bronchodilator-containing regimen, to strengthen the patient selection process.
While pharmacy claims demonstrate that a prescription was filled, whether patients took the medication as prescribed is unknown.
No single TT inhaler was available for the entire study period (unlike TIO+OLO). Use of multiple inhalers may be less convenient and more expensive for patients, and could potentially impact outcomes despite the on-treatment study design.
Results of this study are based on a population of MAPD enrollees and may not be generalizable to patients with COPD who have other forms of insurance or are uninsured.