This suggests that patient education on the proper use of inhalers is more important to controlling asthma than the selection - or indeed the design - of the inhaler device.
"Health-care providers should avoid basing device selection exclusively on device efficacy. Instead, the choice should be based on other patient-related factors," according to the guidelines, which have been drawn up by the American College of Chest Physicians (ACCP) and the American College of Allergy, Asthma, & Immunology (ACAAI) and published in the January edition of Chest.
The guidelines - the first ever drawn up to cover this topic - were developed by an international panel of pulmonary experts and provide recommendations on overall device selection and device selection for several commonly encountered clinical settings.
Based on a systematic review of pertinent randomised, controlled trials, panel members compared metered-dose inhalers (MDIs) with or without spacers/holding chambers, dry powder inhalers, and nebulisers, delivering both bronchodilators (beta2 agonists) and inhaled corticosteroids in order to determine the best recommendations for device selection.
They conclude that doctors should not consider the type of device in prescribing decisions but focus instead on other issues, including device availability; cost; convenience; and the patient's age, competence in using the device, and preference.
"The current practice of device selection for the delivery of aerosolised asthma or COPD medication is largely based on the device's effectiveness in delivering the medication to the patient. Although there are advantages and disadvantages associated with each device and medication, when used properly, all aerosol devices can work equally well and can be interchanged," said guidelines chair Myrna Dolovich of McMaster University in Canada.
The guidelines also incorporate recommendations for device selection in specific clinical settings, including the emergency department, ICU, and inpatient and outpatient situations. For example, nebulisers and MDIs with spacer/holding chambers are appropriate for use in the inpatient setting and for bronchodilators in the emergency department.
Panel members also strongly recommend that clinicians provide patients with sufficient instruction on the use of their aerosol inhaler in order to maximize asthma control.
"Many health-care providers are confused by the large number of aerosol delivery devices available and have difficulty explaining their correct use to patients," said Prof Dolovich. She said they should be familiar with issues related to performance and correct use of aerosol delivery devices in order to instruct their patients on proper usage.