Influence of Gender on Inhaler Technique

Discussion

Our findings in a cohort of subjects with COPD and asthma revealed a higher prevalence of subject-reported difficulties with using inhalers in female subjects than in male subjects, whereas technician-reported errors in inhaler technique were similarly high in both genders. A longer duration of inhaler therapy predicted a higher likelihood of correct inhaler technique, whereas a lack of training on inhaler technique predicted a higher likelihood of errors in inhaler technique and change of inhaler device. A change of the inhaler device was based on the physician’s decision in most cases, followed by difficulties with inhaler use and failure to sense the drug.

pMDIs require good hand–lung coordination and are therefore considered to be inherently more difficult to use and are associated with a larger numbers of errors in inhaler technique compared to DPIs.^7-9,14-17 High rates for pMDI therapy in our cohort seem notable in this regard, given the high rates of poor inhaler performance, regardless of the gender. However, while suboptimal inhaler technique is more likely with the pMDI type of inhaler,^3,5,18-20 such technique is in fact considered to be very common with both pMDIs and DPIs, despite advances in inhaler device technology.^1-5

Device handling for pMDIs and inhalation maneuvers for DPIs are considered to be the most common errors in inhaler technique.¹³ Data from a large systematic review revealed a high frequency of poor and suboptimal inhaler use for all types of devices, with the highest average frequency of errors for pMDIs and high rates of errors in preparation, full expiration, and breath-hold maneuvers for DPIs.⁵ Supporting the high frequency of incorrect inhaler use and the nature of the most common errors in inhaler technique reported in previous studies,⁵ errors in inhalation maneuvers were common to all types of inhalers in our study, including pMDI and DPIs. This emphasizes the risk of insufficient drug delivery to the lungs and limited effectiveness of the medication.^3,4,21-24

In our cohort, technician-reported rates of errors were higher than subject-reported rates in terms of inhalation maneuvers. Notably, whereas only 57% of female subjects and 41% of male subjects reported difficulty with remembering to exhale before inhaling and none reported difficulty with deep inhalation, a direct observation of the subjects’ performance revealed the failure to exhale before inhaling in 80% of subjects and failure to deeply inhale in 50% of subjects, regardless of gender. This supports the consideration that patients overestimate the correctness of their inhaler technique with high levels of confidence, despite high rates of errors upon direct observation.⁹

Nonetheless, higher rates of self-reported difficulties by female subjects seem to emphasize the likelihood of better recognition of individual inhaler performance among female subjects or a lower self-confidence in their abilities. Low health literacy and low educational attainment are considered potential factors in poor inhaler technique, although not as barriers against responding well to interventions to improve the inhaler technique.^16,17 Hence, the higher rate of self-reported difficulties among the female subjects in our study may be related to the consideration of certain factors that challenge the individual inhaler performance by female subjects who otherwise believe they display a much better performance. For example, a higher rate of illiteracy in female subjects than in male subjects (38.4% vs 7.6%) in our cohort may be one of these factors, as well as the likelihood of limited time for self-care among female subjects, given that they are considered to be the primary individual responsible for child care and all household tasks in the Turkish culture. Our results emphasize a need for inhaler training beyond written materials for improving inhaler techniques among female patients in relation to the association of illiteracy with a limited ability to interpret written materials.¹⁶

In a past study on inhaler errors, although a self-rating score for inhaler use was reported to be associated with a higher likelihood of correct inhaler technique overall, the authors reported no significant difference in the self-rating scores of subjects with versus those without critical errors in inhaler technique.¹⁰ Accordingly, our results emphasize the crucial role of training by health care professionals in improving inhaler technique, particularly for critical errors, which are likely to significantly impair the delivery of adequate medication to the lungs.^2,4,21,25-27 With a similar duration of inhaler therapy and similar rates of training on inhaler use between female subjects and male subjects, our results indicate that a longer duration of inhaler therapy predicts a higher likelihood of correct inhaler technique, and a lack of training on inhaler technique predicts a higher likelihood of errors in inhaler technique and change of inhaler device. In addition, our results support past studies showing a decline in correct inhaler technique with aging.^4,9,21,28-30

The basics of effective inhaler training are considered to be simplification, demonstration, and repetition.^8,31 Subjects receiving repeated instructions over a period of time and regular follow-up^23,32-34 were reported to demonstrate improved performance of handling inhaler devices, while a longer duration of therapy was associated with a proper inhaler technique.³⁵ However, inhaler technique is considered likely to deteriorate again after education, along with a steep increase in the number of errors among patients using devices for a longer duration.^8,23,36,37 This seems to emphasize a need for regular reassessment and intermittent checkups regarding inhalation techniques to prevent overconfidence of patients in their performance and to reinforce the correct inhalation technique.^8,23,36,37

Along with a lack of previous training in almost 30% of our subjects, repeated evaluation of inhaler technique at follow-up visits was evident only in 30% of subjects. Accordingly, our findings support the critical importance of structured and detailed patient education on inhaler techniques,³⁸ as well as physician awareness regarding the close follow-up of patients with repeated evaluations of inhaler techniques and correction of suboptimal techniques with tailored in-depth support.^21,23,32

The major strength of this study is the comparative assessment of inhaler techniques in a large-scale cohort of female and male subjects through a self-reported rating as well as through direct observation of subject performance across a large array of device types in accordance with real-life clinical practice conditions. However, certain limitations to this study should be considered. First, the cross-sectional design limits the interpretation of the findings and the ability to establish any cause and effect relationships. Second, a potential lack of generalizability due to the single-center design of the study is another important limitation. Third, the inhaler technique was assessed based on frequently used types of inhalers, and several types of infrequently used inhalers were not included in the analysis. Third, a lack of data on subject confounders (eg, cognitive status and vision or hearing capabilities) with a potential impact on inhaler technique is another limitation that would otherwise extend the results of our study. It should also be noted that although there are many pMDIs containing solution-form drug (eg, QVAR, Albesco, Flutiform) that do not require shaking before use; these pMDIs are not available in our country. In addition, loss through mouth/nostrils was noted in almost half of our subjects, which seems to be a very high error rate for a step that may be valid only for aerosolized medicine. Finally, while the data on the error of shaking the inhaler before use was presented only for Turbuhaler users in accordance with inclusion of only the top 10 errors in this analysis, it should be noted that the correctness of this maneuver is also required in other devices that have a “never shake” direction in the manufacturer instructions (eg, Diskus type inhalers).