Inhalation Technique Errors with Metered-Dose Inhalers Among Patients with Obstructive Lung Diseases: A Systematic Review and Meta-Analysis of U.S. Studies.

Background Metered dose inhalers (MDIs) are commonly prescribed for inhalation therapy, but correct use is critical to promoting effective medication delivery. This systematic literature review and meta-analysis evaluates the overall and step-by-step prevalence of errors among adults with obstructive lung diseases in the United States who used MDIs. Methods Electronic and manual searches conducted between 1979-2018 using PubMed, EMBASE, PsycINFO, Cochrane, and Google identified 10 articles that met the following inclusion criteria: (a) English language, (b) U.S. adults diagnosed with chronic obstructive pulmonary disease, and (c) MDI use error rates. Meta-analytic techniques using random-effects models were applied to calculate effect sizes, weighted proportions, and 95% confidence intervals (CIs). Heterogeneity was assessed by the I2 statistic. Results Aggregate findings revealed that 86.7% of patients (n=390, 95% CI 77.5-96.0) made at least 1 inhalation technique error, and 76.9% (n=885, 95% CI 65.8-87.9) incorrectly performed ≥ 20% of device use steps. The most prevalent step-by-step errors across the studies (n=1105) were failure to: (a) exhale fully and away from the inhaler before inhalation (65.5% [95% CI 52.0, 78.9]); (b) hold breath for 5-10 seconds (41.9% [95% CI 29.8, 53.9]); (c) inhale slowly and deeply (39.4% [95% CI 26.2, 52.5]); (d) exhale after inhalation (35.9% [95% CI 17.0, 54.8]); and (e) shake the inhaler before use (34.2% [95% CI 30.6, 37.7]). Conclusions Across the studies used in this meta-analysis more than three-fourths of U.S. adults with obstructive lung diseases used MDIs incorrectly. Our findings suggest the need for ongoing patient education and consideration of alternative devices to mitigate errors.