Correct Use of Pressurized Metered-Dose Inhalers and Its Predictors among Patients Attending a Respiratory Medicine Outpatient Department in Eastern India

Background: Incorrect use of pressurized metered-dose inhalers (MDIs) compromises drug delivery in asthma and chronic obstructive pulmonary disease (COPD) management, with global error rates up to 94%. This cross-sectional study evaluated MDI technique correctness and predictors among patients in a respiratory outpatient department in Eastern India, addressing a local research gap. Methods: Purposively sampled 115 patients aged >12 years using MDIs were assessed over 1 month, excluding severely ill cases, active tuberculosis, or interfering comorbidities. Observational checklists based on National Heart, Lung, and Blood Institute 2021 guidelines and Newman critical steps (shaking inhaler, full exhalation, actuation–inhalation coordination, ≥10-second breath-hold) were used during interviews with dummy inhalers. Sociodemographics, disease, and MDI variables were analyzed via SPSS v20 (means ± standard deviation, percentages, Mann–Whitney U , Fisher’s exact; P < 0.05 significant). Results: Mean age was 50 ± 14.5 years; 50.4% male, 67% rural, 51.3% secondary-educated, 34.8% socioeconomic status (SES) class V. Patients were diagnosed with asthma in 46.9%, COPD in 36.5%, and others 16.5%. Only 14.8% had no critical errors (85.2% had ≥1); key errors: 59.2% inadequate breath-holding, 53.9% incomplete exhalation, 29.6% poor coordination. Shorter MDI duration predicted errors (median 5.5 vs. 36 months, P = 0.043); no associations with age, sex, education, and residence ( P > 0.05). Conclusion: With an 85.2% critical error rate, routine reinforcement of key MDI steps, especially for short-term users, rural, and low-SES patients, is essential to enhance respiratory outcomes.