PURPOSE: Dry powder inhalers are often used ineffectively. This observational study investigated how often essential mistakes are made in the use of the Aerolizer, Discus, HandiHaler and Turbuhaler as well as the influence of age, severity of airflow obstruction and training in inhalational technique.
METHODS: The study comprised 224 newly referred outpatients (age 55.1±20 years) who presented with one of these inhalers. The patients were asked how they had been acquainted with the inhaler and to demonstrate their inhalational technique.
RESULTS: The overall error rate was 32.1%. The inhaler-specific error rates were as follows: Aerolizer: 9.1%, Discus: 26.7%, HandiHaler: 53.1% and Turbuhaler: 34.9%. Compared to the Aerolizer, the odds ratio of an ineffective inhalation was higher both for the HandiHaler (9.82, 95%-CI: 1.84–52.38, p<0.01) and the Turbuhaler (4.84, 95%-CI: 1.06–22.02, p<0.05). The error rate increased with age (20.0% at age < 60 years versus 41.6% at age > 60 years; p<0.01) and with the severity of airway obstruction (25% in normal lung function versus 63.6% in severe obstruction; p<0.01). When instruction in inhalational technique was given by medical personnel as opposed to no training at all, the odds ratio of ineffective inhalation was 0.22 (95% confidence interval 0.12-0.41; p<0.01). If the Turbuhaler is used, the estimated risks range from 9.8% in an 18-year patient with normal lung function and previous training to 83.2% in an 80-year old patient with moderate or severe obstruction who had not received any training.
CONCLUSION: Inhaler type, age, severity of obstruction and prior training in operating the inhaler determine the risk of ineffective inhalation.
CLINICAL IMPLICATIONS: Dry powder inhalers are useful in the management of younger patients with normal lung function or mild obstruction. In older patients the risk of ineffective inhalation remains high despite training. Especially older patients with advanced COPD should demonstrate their inhalational technique at every health care encounter. If crucial handling errors cannot be eliminated, a metered-dose inhaler in combination with a spacer might be a valuable treatment alternative.
DISCLOSURE: Siegfried Wieshammer, No Product/Research Disclosure Information; Consultant fee, speaker bureau, advisory committee, etc. S.W has received 500 Euro from AstraZeneca and 1600 Euro GlaxoSmithKline for arranging educational courses and for speaking at scientific conferences sponsored by these companies wthin the past 12 months. J.D. has no financial relationship with any commercial entity that might have an interest in the subject of this abstract.