Introduction
Although inhalation is the route of delivery of choice in the treatment of asthma, inhalers are often used incorrectly.1-7 Many patients have received no instruction in inhalation technique (IT), and even many health care professionals do not know the correct steps.8-11 Earlier studies have evaluated the skills of patients with asthma in the use of pressurized canister inhalers (PCI), but data on the use of other devices are scarce. Few studies of this type have been done in the primary care setting. Despite the publication of clinical practice guidelines,12-15 we suspect that IT is still often performed incorrectly. This led us to investigate our patients' skills in performing the steps needed to use different inhalation systems, and the variables that can influence correct performance.
Methods
Study design
Descriptive, cross-sectional study.
Participating center
An urban primary care center and primary care staff.
Study group selection
We included all patients aged 18 to 80 years and diagnosed as having asthma who were registered with the program at our center (n=281 patients).
Inclusion criteria
Seen for more than 1 year for asthma, and 1 or more prescriptions for inhaled medications during the preceding 2 years.
Exclusion criteria
Declining to participate in the study, missing an appointment or not locatable, problems traveling to the center, incapacitating neurological or psychiatric disorders, terminal neoplasm, or advanced AIDS.
We reviewed the clinical history of all patients to record the following variables: sex, age, educational level, year of diagnosis, classification of asthma according to the GINA 98 system,16 treatment, inhalation system used, and physician responsible for the patient. With the doctor's or nurse's permission, each participant was contacted by telephone (up to four attempts) at different times of day to schedule an individual appointment for an IT test. If no phone number was recorded, we went to the patient's home.
On the basis of these inclusion and exclusion criteria, a total of 141 patients were recruited to investigate IT.
Description of the IT evaluation test
Each patient was asked to demonstrate how they used their inhaler; no information was provided prior to the test. Each step in the process was checked in accordance with SEPAR-semFYC guidelines.12,13 For scoring purposes the technique was broken down into several steps; for each step performed correctly, 1 point was scored. The technique was considered incorrect when the total score was >9. For patients who used more than one inhaler system, the results were analyzed separately for each device. If one of the techniques was performed incorrectly, the patient's IT was considered incorrect.
Outcome measures
Main outcome variable: percentage of patients with correct IT. We analyzed the percentage of patients with correct IT for each inhalation system separately, and for all systems globally. The percentage error rates were compared for each step and for each system. As secondary variables we analyzed factors that could influence IT performance.
Statistical analysis
Ninety-five percent confidence intervals for the percentage error rates were calculated, and bivariate analysis was done with comparison of the means (Student's t test) and comparison of the proportions (χ2). All analyses were done with version 10.0 of the SPSS.
Results
Of the 141 patients, 77.3% (n=109) were women, and mean age was 56.08 (SD, 18.0) years. The different inhalation systems used by our patients are shown in Table 1. About three-fourths of the patients (73.8%) used only one inhalation device (n=104), 21.3% (n=30) used two systems, and 5% (n=7) used three, thus the total number of inhalation systems we checked in this study was 185. When the only device used was a PCI, the active principle was a short-acting ß2 in 90% of the prescriptions. When more than one system was used, a PCI was one of the devices used by most patients.
Overall, IT was incorrect in 53.9% (n=76) of the patients. The Accuhaler and Turbuhaler systems yielded the highest scores (correct IT in 62.5% and 61.5% of the patients, respectively). The system that yielded the highest percentage of errors (59.1%) was PCI+spacer (Table 1).
The steps with the highest percentage error rates for all inhalation systems are shown in Table 2. Younger patients and patients with a higher educational level more frequently used inhalation systems correctly (P=.007) (Table 3).
Mean age of the patients who used different systems was: Turbuhaler, 42.5 (±18.82) years; Accuhaler, 68.25 (±2.87); PCI, 55.48 (±21.21; PCI+spacer, 64.28 (±14.63), and dry powder inhaler, 41. The percentage of patients who had received university-level education, by inhalation system, was Turbuhaler, 36.5%; Accuhaler, 18.8%; PCI, 14.9%, and PCI+spacer, 7.6%.
There were no statistically significant differences in the percentage rates of correct IT and any of the other variables shown in table 3 (P>.05).
Discussion
Studies of the prevalence of asthma indicate that 1% to 5% of the population have this disease.14,17 In our study, 1.8% of the population had asthma. The higher percentage of asthma in women may reflect their greater use of health care services. Underrecording was found for both the prevalence and classification of asthma. This finding may reflect the fact that health care staff are less aware of this disease than they are of others. As reported in an earlier study,3 a large percentage of our patients used their PCI without a spacer. The fact that most patients used short-acting ß2 on an as-needed basis may account for this finding.
Patients who were taking different medications via a PCI used a spacer, as recommended by current guidelines.13-15 Use of a single inhalation system is advisable to favor compliance with instructions for IT.18
In the present study we found that IT was worse in patients who used more than one inhaler. The number of errors was proportional to the number of devices used, although this relationship was not statistically significant. As in other studies, the percentage of patients with incorrect IT was high.1-5,9-11 The similarities in error rates may reflect inadequacies in the instructions patients receive.3 As in other published studies, the steps that were most frequently performed incorrectly were exhaling completely before inhaling the dose1-3 and holding the breath after inhalation.1,2,4 Patients who used a Turbuhaler made fewer mistakes.
When we analyzed the relationship between mean age and level of education and the inhalation system used, we found these variables to be confounders in our attempt to identify the best inhalation system: the system that appeared to be the best (Turbuhaler) was used predominantly by younger patients with a higher level of education. To offset the influence of these confounders we stratified the results by age group and re-examined the results to identify which inhalation system was used best in each subgroup. In both age subgroups (i.e., in patients older than and younger than 65 years), the inhalation devices that were used correctly most often were Turbuhalers and Accuhalers, although the difference in comparison to other systems was not statistically significant (probably because of the small sample size).
Our findings suggest that the Turbuhaler device is superior to the rest. However, to confirm this, patients would need to be selected in a manner that ensured a homogeneous distribution, in terms of age and level of education, of participants who use different inhalation devices. Our results also suggest that when a specific inhalation system is singled out for analysis, each case should be dealt with individually according to the subject's characteristics.4,13,14 As in other studies, the variables that were most clearly related with correct IT were age4 and level of education.3
In conclusion, we note a large percentage of our patients with asthma had errors in their inhalation technique. Health education efforts to teach patients how to use different inhalation devices correctly should be stepped up. Our study does not allow us to conclude that any one inhalation device is superior to the others. Future research will compare IT performance with different inhalation devices, taking into account the confounding factors identified above. We will also evaluate whether educational group workshops are effective in improving inhalation technique.
Correspondence: Montserrat Rodríguez Mas. C/ Torras i Bages, 1. 08290 Cerdanyola del Vallès (Barcelona). España. E-mail: montserodmas@hotmail.com
Received 11 December 2002. Accepted for publication 21 May 2003.
