The current study investigated the factors influencing medication adherence to inhalers in patients with COPD and asthma based on the Anderson Model.
Adherence status
The findings revealed that a significant proportion of patients exhibited poor adherence to inhaler use. These results are consistent with similar studies conducted nationally and internationally. Humenberger et al. found that only 33.6% of 357 COPD patients were fully adherent to inhalation therapy, with a slightly higher rate observed in patients with more severe COPD [12]. Likewise, Zhang et al. assessed inhaler adherence in patients with COPD and asthma and found good adherence in only 19.83% of patients [13]. Bereznicki et al. reported similar results, founding good adherence in 19.4% of asthma patients [14]. Low adherence to inhaler uses among patients with asthma and COPD is compounded by a notable rate of errors in administering inhalers [15–17]. These studies collectively highlight the urgent need for further exploration of its formation and influencing factors of low adherence, aiming to develop effective management and intervention strategies.
Poor adherence has been associated with increased mortality rates, reduced quality of life, higher direct and indirect costs for patients, as well as inadequate symptom control and disease progression [1, 18–20]. Addressing the factors contributing to poor adherence is, therefore, a critical research topic in the management of an essential research topic in asthma and COPD.
Contextual characteristics
In this study, contextual characteristics such as Inhalator operation, medical accessibility, possession of chronic disease cards, health insurance type, residential status, and spouse situations were explored as potential factors influencing inhaler adherence.
It has been shown that repeated instruction of patients in inhaler handling techniques improves their inhaler medication adherence [21]. However, in the analysis of the relationship between inhaler operation and adherence in this study, we did not find a statistically significant correlation. We hypothesize that this could be due to the limitations imposed by the COVID-2019 pandemic, preventing face-to-face interactions and interviews with most patients. Consequently, the thorough investigation of patients' inhaler usage skills might not have been fully realized. It's possible that patients were either unaware of or intentionally concealed issues related to their inhaler operation.
Regarding medical accessibility, it was surprising to find that there was no statistically significant effect on inhaler adherence. This may be because although rural patients have access to village health offices and township health centers, these institutions may not provide inhalers. Consequently, patients are unable to purchase inhalers, limiting the impact of medical accessibility on adherence.
However, patients who possessed appropriate chronic disease cards demonstrated better adherence to inhalers compared to those without. This finding can be attributed to the difference in out-of-pocket costs for inhalers. Reducing these costs has been shown to improve medication adherence for patients with chronic diseases [22]. Rural elderly patients with limited financial resources may opt not to adhere strictly to their medication regimens or even discontinue medication due to the high costs of inhalers without the appropriate chronic disease card. These findings emphasize the importance of improving medical assistance policies, implementing health insurance reimbursement programs, and alleviating the financial burden on patients with chronic diseases.
Residential status was found to impact patient adherence, with patients living with their children/parents or spouse and children/parents exhibiting better adherence compared to those who live alone [23, 24]. Family members can provide medication assistance, encourage timely medication intake, assist with purchasing medication, and offer guidance on inhaler use. This support is particularly crucial for elderly patients or those with memory loss and mobility difficulties. Therefore, interventions to improve inhaler adherence should involve not only the patient but also their family members. Educating patients' families about correct inhaler operation, the necessity of inhalation therapy, and disease medication knowledge enables them to provide positive guidance and support. Additionally, community involvement through grassroots social management interventions can provide advocacy, education, and support to patients in the community.
The study did not find a statistically significant difference in inhaler adherence based on different spouse situations. This may be because some patients, due to their diseases, are left alone at home while their spouses work outside or are unable to provide effective help. As a result, the spouse's situation may have limited influence on the patient's adherence to inhaler.
Contrary to expectations, the study did not find a statistically significant difference in inhaler adherence based on patients' usual residence (urban or rural). This may be due to some patients who work outside the city not being eligible for the chronic disease policy in the city where they work. Consequently, they have to bear the full cost of inhalers. The lack of community and family support further hinders strict medication adherence due to financial and social factors.
Individual characteristics
Regarding individual characteristics, disease type, family history of related diseases, patient beliefs about medication, and education levels were examined as potential factors influencing inhaler adherence.
The results indicated a relationship between disease type and inhaler adherence. COPD patients exhibited better adherence behavior compared to asthma patients, which aligns with previous findings [25]. The variance in medication adherence rates between COPD and asthma can be attributed to several factors, including the divergent nature of the diseases and the demographics of their respective patient populations. COPD patients typically exhibit advanced age and a higher prevalence of comorbidities, alongside experiencing more persistent and severe symptoms compared to asthma patients. Additionally, the progressive and irreversible nature of COPD symptoms may inherently necessitate stricter medication adherence. Conversely, asthma manifests with variable airflow obstruction that can often be alleviated with medication, potentially leading to lower adherence rates. As a result, it is crucial to develop tailored intervention programs that address the unique characteristics and duration of each patient's disease.
Patients with a family history of related diseases demonstrated better inhaler adherence compared to those without such a history. This may be because individuals with a family history are exposed to the disease earlier and possess more knowledge about medication. They have a better understanding of their disease's characteristics and the importance of medication. Additionally, as family members of patients, they can enhance their own adherence while supervising their family members.
Patient beliefs about medication also play a significant role in inhaler adherence. The stronger the patients' perceived need for using inhalers, the better their adherence. Conversely, the more concerns patients have about using inhalers and the more serious these concerns are, the poorer their adherence becomes. This finding is consistent with previous study [26]. Therefore, when intervening to improve inhaler adherence, it is crucial to respect the patient's subjective status regarding medication and pay close attention to their views and beliefs. Strengthening medication education to address patients' concerns can help them understand the benefits and necessity of inhalers for disease control and health promotion. Additionally, patients should be encouraged to view the adverse effects of medication rationally and dialectically.
Contrary to our expectations, differences in inhaler adherence among patients with different education levels were not statistically significant. This may be because the majority of patients included in the study had a lower level of education. As a result, there were limited variations in educational backgrounds among the patients. Many of them lacked an understanding of their disease, proper medication usage, and inhaler technique due to their older age and limited receptiveness to new information. Hence, educational interventions should be tailored to the specific needs of these patients, focusing on improving their knowledge and skills related to inhaler use.
Outcomes
In Anderson's model, we consider the health status as the outcomes dimension. Surprisingly, our study did not find a statistically significant correlation between patients' health status and inhaler adherence. This result aligns with the findings of Vicente Plaza et al., who also observed no clear correlation between adherence and asthma control or the health status of patients with asthma and COPD [10]. However, it is important to avoid drawing hasty conclusions about the relationship between inhaler adherence and health status based solely on these correlation analysis results. Although we were unable to conduct a pilot intervention study due to study limitations, previous research has shown that improved inhaler adherence can lead to benefits in disease prevention, control, and quality of life for individuals. Subsequently, we found that the difference between the health status values of patients with average adherence and those with poor adherence was statistically significant by one-way ANOVA post-hoc comparisons after dividing the patients into different grades of adherence, and that the difference between the health status values of patients with good adherence and those with good adherence was not statistically significant in either of the other two cases. One of the reasons may be that COPD disease is irreversible and the clinical symptoms are more serious, COPD patients have good adherence, but the health status is still unsatisfactory [27–29]. Good adherence has been linked to reduced exacerbation rates and improved lung function in patients with COPD and asthma, ultimately contributing to improved overall health status. It's important to note that the relationship between medication adherence and quality of life can be complex. Adherence may positively impact quality of life through improved health outcomes, but it may also lead to negative outcomes such as adverse events or limitations in daily life[30]. Quality of life can also influence medication use, as improved quality of life may unexpectedly lead to non-adherence when symptoms improve, with some patients reducing or stopping the use of inhalers once their symptoms resolve. Moreover, the effect of medication on improving quality of life can profoundly influence patient adherence to inhaler therapy. For instance, the swift enhancement in quality of life linked with the use of Short-Acting Beta Agonist (SABA) inhalers differs from medications such as Inhaled Corticosteroids (ICS), which may require several days to alleviate inflammation. The rapid response of SABA inhalers in enhancing quality of life may foster better adherence among patients, despite the fact that prolonged use of SABA inhalers is no longer recommended. Although this study did not include patients with acute exacerbations or severe disease, there were still differences in disease severity and health status among the included patients. Some patients with longer disease duration and poorer health status may exhibit good adherence but limited benefits due to irreversible damage. Conversely, patients with fair or poor adherence but shorter disease duration may have better health status. Additionally, it's important to note that most of the patients in this study were elderly and likely had comorbidities, which can also affect their health status. Unfortunately, our study did not explore patients' comorbidities, which is a limitation. Moreover, the interaction between medication adherence and quality of life may vary over time, with the negative effects of non-adherence becoming more dominant in the long run [31].
Management and intervention recommendations
In this study, we propose intervention strategies in four areas. These recommendations have already been implemented in certain hospitals in China with good results.
From a national perspective, it is imperative to further enhance and refine the subsidy framework for individuals diagnosed with Chronic Obstructive Pulmonary Disease (COPD) and asthma. Concurrently, adjustments to pertinent health insurance policies are warranted to mitigate the ongoing financial strain arising from the sustained medication needs of patients. Simultaneously, strategic policies should be implemented to guarantee the availability of inhalation devices in hospitals across all tiers, thereby augmenting the accessibility of these devices for a broader patient demographic. This multifaceted approach aims to facilitate increased inhaler procurement by patients, ultimately optimizing the management of COPD and asthma while alleviating economic burdens.
At the societal level, community staff should actively collaborate with healthcare professionals. In the management of patients' chronic diseases, communities should enhance the dissemination of pertinent chronic disease policies to patients. This involves regular organization of activities, including health education sessions and group lectures addressing diseases and medication. Additionally, patients' family members can play a role in supervising and reminding patients to adhere to medication regimens and assisting them in acquiring correct inhalation techniques. This comprehensive approach aims to bolster the support system for individuals with chronic respiratory conditions, promoting effective disease management.
From the physician's perspective, it is advisable to establish an inhalation therapy record for each patient. This record would facilitate intervention in patients' medication compliance, taking into account factors such as the drug itself, its efficacy, the type of the patient's disease, as well as the patient's individual circumstances, disease characteristics, medication preferences, and the distinctions among various inhalers. Nurse can contribute by delivering personalized education to patients and their families. This involves demonstrating the proper operation of the inhaler and assisting patients and their families in acquiring the correct usage techniques. Pharmacist, on the other hand, can play a pivotal role in intervening with patients' drug education, disease knowledge, and beliefs about medication. They can conduct regular visits based on patients' treatment records, promptly address patients' inquiries with their professional expertise, alleviate medication-related concerns, and encourage adherence to inhalation therapy in accordance with medical advice. This comprehensive approach aims to enhance patient understanding, skills, and compliance with inhalation therapy.
At the individual patient level, it is crucial to enhance self-management and actively collaborate with prescribed treatments. When uncertainties arise regarding the disease or medication, it is important to proactively seek assistance from physicians, nurses, pharmacists, and family members. Trusting healthcare professionals is integral to establishing accurate knowledge and beliefs about medication. Maintaining a healthy lifestyle by refraining from smoking and excessive alcohol consumption is paramount. It is equally important to avoid non-adherence to medication stemming from misconceptions about the disease and its treatment. This proactive approach supports effective self-management and contributes to overall treatment success.
Limitations
This study did not stratify patients based on disease severity, limiting the exploration of the relationship between patients' adherence to inhalers and their disease severity. During telephone interviews, many elderly patients with advanced age and severe disease were missed, introducing some sampling bias. Additionally, due to the ongoing impact of COVID-19, there was limited time to collect questionnaires in the outpatient clinic, resulting in a lower number of collected questionnaires. Furthermore, specific administrative and research conditions made it impractical to conduct a rigorous experimental study of the intervention, and some influencing factors and intervention recommendations obtained from the study may require further confirmation. Additionally, the study did not separately examine the effect on adherence between medications with immediate effects (e.g., SABA) and those with delayed effects (e.g., ICS). Future research endeavors aim to focus more precisely on adherence to ICS inhalers.