Determinants of Inhaler Choice at Hospital Discharge

<b>Background</b>: Inhaler device changes at hospital discharge should address patient capacity yet often reflect routine. We evaluated the appropriateness of these decisions and their impact on clinical outcomes. <b>Methods</b>: In this prospective observational study (<i>N</i> = 480), we assessed patient technical capacity using a composite of critical errors, inspiratory flow, adherence, and knowledge. We stratified patients into 'Need-Positive' and 'Need-Negative' cohorts to quantify patterns of clinical inertia and over-adjustment. Multivariable models identified predictors of decision-making and associations with 30-day outcomes. <b>Results</b>: Device changes were primarily determined by the pre-admission device class (spacers: aOR 0.52; 95% CI 0.28-0.96; <i>p</i> = 0.037) and by the patient's treatment pathway rather than by clinical need. This disconnect generated two types of errors: 38.3% of Need-Positive patients (<i>n</i> = 214) experienced clinical inertia (no corrective action), while 36.8% of Need-Negative patients (<i>n</i> = 266) underwent over-adjustment (unnecessary switching). Inertia perpetuated errors in patients with need, whereas over-adjustment was associated with the emergence of new errors in patients without need. Successful mismatch resolution was associated with a significantly lower 30-day readmission rate (12.1% vs. 32.5%; OR 0.48; 95% CI 0.26-0.88; <i>p</i> = 0.017). <b>Conclusions</b>: Discharge prescribing is driven more by habit than by objective assessment, leading to widespread missed opportunities for correction. Implementing evidence-based protocols to identify and resolve patient-device mismatches may represent a high-impact strategy to reduce readmissions and associated healthcare use.