Uncontrolled Asthma Linked to Miscounting Inhaler Doses

Kohei Hasegawa, MD, MPH

Half of patients admitted to an emergency department for uncontrolled asthma had unknowingly emptied their bronchodilator inhaler, and half of those patients were unfamiliar with identifying remaining doses, in a study conducted at 3 emergency departments (ED) in Boston.

Although most inhaler products incorporate a dose-counting meter, in response to a 2003 recommendation of the US Food and Drug Administration (FDA), only one-third of the patients admitted to an ED for uncontrolled asthma had been advised to keep track of available doses.

Led by Kohei Hasegawa, MD, MPH, attending physician, Massachusetts General Hospital and Associate Professor of Emergency Medicine, Harvard Medical School, researchers noted that overestimating the remaining doses of short-acting beta-agonist (SABA) can cause patients to use their inhalers past the labeled actuations. They noted that the drug delivered per actuation can range anywhere from 20% to 80% of the needed therapeutic dose.

Hasegawa and colleagues conducted the observational cohort study in the emergency departments (EDs) of Beth Israel Deaconess Medical Center, Brigham and Women's Hospital, and Massachusetts General Hospital from 2015-2017 as part of the Multicenter Airway Research Collaboration (MARC), a program of the Emergency Medicine Network research consortium.

The investigators identified 203 adult patients 18-54 years of age (median 32 years old) with history of asthma and current prescription for a SABA inhaler, who were admitted to the ED with asthma exacerbation. Two-thirds of patients were female, 40% were non-Hispanic white, and 52% had public insurance.

Although most (86%) of the patients had a primary care physician, 55% indicated they preferred to use an ED for asthma care. Two-thirds of patients did not have a written action plan for asthma control.

Patients were asked in a structured interview how they identified remaining doses of the inhaler, and their inhaler use technique was objectively evaluated. Although 92% of the patients' inhalers incorporated a dose counter, only 24% reported using it, while 32% of patients used a test spray to determine whether their inhaler contained medication. The most common error in using the inhaler was to not exhale before dose actuation (79%), and not holding breath after inhaling the dose (63%).

Hasegawa and colleagues attribute the suboptimal use of asthma inhalers to multiple factors, including insufficient education of patients on dose counting and underutilization of written action plans.

They suggest that both could be symptoms of other problems, “such as provider-related factors (inadequate time, staff, and infrastructure for self-management education, and social determinants of health (limited access to healthcare).”

Others who have found that inhalers are often used improperly have also implicated system failures before individual health behaviors.

In their review of errors in inhaler use, Joaquin Sanchis, MD, PhD, Universitat Autònama de Barcelona, Barcelona, Spain and colleagues wrote that incorrect inhaler technique is “unacceptably frequent and has not improved over the past 40 years, pointing to an urgent need for new approaches to education and drug delivery.”

The study, "Dose counting and use of short-acting beta-agonist inhalers in emergency department patients with asthma exacerbation," was published online in Annals of Allergy, Asthma & Immunology.