Respiratory and Peripheral Muscle Strength as Predictors of Inhaler Treatment Response in Asthma: A Comparison of DPI and MDI Devices

Asthma is a chronic respiratory disease characterized by variable airway obstruction. Inhaled therapies are the cornerstone of asthma management, and selecting the appropriate inhaler device is essential for effective treatment. Among available devices, metered dose inhalers (MDIs) and dry powder inhalers (DPIs) are commonly used; however, their effectiveness depends not only on the medication but also on the patient's physiological capacity and inhalation technique.

This prospective randomized study aimed to evaluate the factors influencing inhaler treatment response in newly diagnosed asthma patients. A total of 80 patients with at least a high school education, who demonstrated perfect inhaler technique and adherence, were randomly assigned to MDI or DPI groups (n = 40 each). Baseline and one-month follow-up assessments included pulmonary function tests (PFTs), inspiratory and expiratory muscle strength measurements (MIP, MEP), Asthma Control Test (ACT), and handgrip strength (HGS).

The study investigated how respiratory and peripheral muscle strength, inspiratory capacity, coordination skills, and clinical status affect treatment outcomes with MDI and DPI. Findings from this research may help guide inhaler selection based on patient-specific physiological characteristics to optimize treatment effectiveness.