Asthma, a common respiratory disorder affects more than 8 million people in the UK alone [1]. Despite the availability of effective treatments, inhaled corticosteroids (ICS) which are the mainstay of asthma treatment, often show limited efficacy because of suboptimal patient adherence. Asthma exacerbations may account for more than 60,000 hospital admissions and more than 1,300 deaths in the UK alone each year [1].
Suboptimal adherence is defined as the failure of patients to take their medication as directed by their clinician [2]. According to a recent review, an estimated 50% of medications for chronic disease are not taken as prescribed [3]. However, asthma adherence rates have been found to be even lower, with adherence estimates ranging from 30% to 70% [4–6].
A need exists to improve medication adherence in asthma to enable more effective asthma treatment. This article will describe those factors that may contribute to poor adherence, potential negative consequences and digital technologies that can aid in improving adherence.
Factors Contributing to Poor Adherence
Those factors contributing to suboptimal asthma adherence can be divided into three categories: medication/regimen, intentional and unintentional factors.
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Medication factors: These are directly related to the medication itself and include the medication costs, complexity of regimens (e.g., multiple times a day), need for multiple inhalers and difficulties using the inhaler devices (e.g., due to arthritis or cognitive decline) [7].
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Intentional factors: These occur because of a patient’s beliefs, choices, or concerns and include the perception the treatment is unnecessary, denial about the illness, inappropriate expectations, concerns about side effects, dissatisfaction with their healthcare provider, and cultural/religious issues [7]
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Unintentional factors: These factors occur in response to unconscious decisions made by the patient such as misunderstanding directions, forgetting to take the medication and the absence of a daily routine [7].
Consequences of Poor Adherence
Poor adherence undoubtedly contributes to the economic and clinical burden of asthma. Already numerous studies have shown that poor medication adherence is associated with worse symptom control in asthma patients [8]. Specifically, better adherence to asthma controller therapy, such as ICS, is associated with a significant reduction in asthma exacerbations, quality of life and asthma-related mortality [8–11]. Notably, one study found that suboptimal adherence to ICS may be responsible for 24% of all asthma exacerbations [12]
Additionally, suboptimal adherence to ICS has been linked to increased hospital admissions, healthcare utilisation and lost productivity [8,9,11]. Suboptimal adherence undoubtedly contributes to direct costs which have been estimated at £1.5 billion and indirect costs due to time off work and loss of productivity, of £4.5 billion [13]
Potential Solutions to Poor Adherence
A need exists to develop interventions to improve asthma medication adherence, of which there are already several successful examples:
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Shared decision-making: Collaborative decisions between patients and their clinicians about medication/treatment are associated with better medication adherence and improved clinical outcomes [14,15].
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Digital interventions: Electronic devices such as smart inhalers and text messages can provide medication reminders and have been associated with improved medication adherence, reduced exacerbations, and improved asthma control in children and adults [16–18].
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Simplified regimens: Reducing dosing frequency (e.g., from twice to once daily) has been shown to be effective in improving patient adherence and quality of life in asthma patients [19].
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Inhaler technique training: Training interventions aimed at improving inhaler technique which is key to enabling effective delivery of therapy have also been shown to be effective in improving medication adherence [20].
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Home nurse visits: Home-based asthma education combined with medication adherence feedback led to improved adherence, better symptom control as well as reduced ED visits and prednisolone use in inner-city children[21].
In conclusion, the problem of poor adherence in asthma is undoubtedly a complex one with many contributing factors and one that can impact the efficacy of asthma treatment. Those interventions aimed at improving adherence have the ability to significantly impact clinical asthma outcomes and healthcare utilisation and costs.
References
[1] British Lung Foundation. Asthma statistic [Internet]. [cited 2023 Feb 3]. Available from: https://public.tableau.com/app/profile/asthmaandlunguk/vizzes
[2] Mäkelä MJ, Backer V, Hedegaard M, et al. Adherence to inhaled therapies, health outcomes and costs in patients with asthma and COPD. Respir Med. 2013;107:1481–1490.
[3] Viswanathan M, Golin CE, Jones CD, et al. Interventions to Improve Adherence to Self-administered Medications for Chronic Diseases in the United States. Ann Intern Med. 2012;157:785.
[4] Rand CS, Wise RA. Measuring Adherence to Asthma Medication Regimens. Am J Respir Crit Care Med. 1994;149:S69–S76.
[5] Bender BG, Bender SE. Patient-identified barriers to asthma treatment adherence: responses to interviews, focus groups, and questionnaires. Immunol Allergy Clin North Am. 2005;25:107–130.
[6] Bateman ED, Hurd SS, Barnes PJ, et al. Global strategy for asthma management and prevention: GINA executive summary. European Respiratory Journal. 2008;31:143–178.
[7] Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention [Internet]. 2023 [cited 2023 Nov 27]. Available from: https://ginasthma.org/wp-content/uploads/2023/07/GINA-2023-Full-report-23_07_06-WMS.pdf.
[8] Mäkelä MJ, Backer V, Hedegaard M, et al. Adherence to inhaled therapies, health outcomes and costs in patients with asthma and COPD. Respir Med. 2013;107:1481–1490.
[9] Ismaila A, Corriveau D, Vaillancourt J, et al. Impact of adherence to treatment with fluticasone propionate/salmeterol in asthma patients. Curr Med Res Opin. 2014;30:1417–1425.
[10] Makhinova T, Barner JC, Richards KM, et al. Asthma Controller Medication Adherence, Risk of Exacerbation, and Use of Rescue Agents Among Texas Medicaid Patients with Persistent Asthma. J Manag Care Spec Pharm. 2015;21:1124–1132.
[11] Bårnes CB, Ulrik CS. Asthma and Adherence to Inhaled Corticosteroids: Current Status and Future Perspectives. Respir Care. 2015;60:455–468.
[12] Williams LK, Joseph CL, Peterson EL, et al. Patients with asthma who do not fill their inhaled corticosteroids: A study of primary nonadherence. Journal of Allergy and Clinical Immunology [Internet]. 2007;120:1153–1159. Available from: https://www.sciencedirect.com/science/article/pii/S0091674907015862.
[13] Asthma+Lung UK. Investing in breath: Measuring the economic cost of asthma and COPD in the UK and identifying ways to reduce it through better diagnosis and care [Internet]. 2023 [cited 2023 Nov 25]. Available from: https://www.asthmaandlung.org.uk/investing-breath-measuring-economic-cost-asthma-copd-uk-identifying-ways-reduce-it-through-better.
[14] Taylor YJ, Tapp H, Shade LE, et al. Impact of shared decision making on asthma quality of life and asthma control among children. Journal of Asthma. 2018;55:675–683.
[15] Wilson SR, Strub P, Buist AS, et al. Shared Treatment Decision Making Improves Adherence and Outcomes in Poorly Controlled Asthma. Am J Respir Crit Care Med. 2010;181:566–577.
[16] Foster JM, Usherwood T, Smith L, et al. Inhaler reminders improve adherence with controller treatment in primary care patients with asthma. Journal of Allergy and Clinical Immunology. 2014;134:1260-1268.e3.
[17] Chan AHY, Stewart AW, Harrison J, et al. The effect of an electronic monitoring device with audiovisual reminder function on adherence to inhaled corticosteroids and school attendance in children with asthma: a randomised controlled trial. Lancet Respir Med. 2015;3:210–219.
[18] Morton RW, Elphick HE, Rigby AS, et al. STAAR: a randomised controlled trial of electronic adherence monitoring with reminder alarms and feedback to improve clinical outcomes for children with asthma. Thorax. 2017;72:347–354.
[19] Price D, Robertson A, Bullen K, et al. Improved adherence with once-daily versus twice-daily dosing of mometasone furoate administered via a dry powder inhaler: a randomized open-label study. BMC Pulm Med. 2010;10:1.
[20] Sánchez-Nieto JM, Bernabeu-Mora R, Fernández-Muñoz I, et al. Effectiveness of individualized inhaler technique training on low adherence (LowAd) in ambulatory patients with COPD and asthma. NPJ Prim Care Respir Med. 2022;32:1.
[21] Otsuki M, Eakin MN, Rand CS, et al. Adherence Feedback to Improve Asthma Outcomes Among Inner-City Children: A Randomized Trial. Pediatrics. 2009;124:1513–1521.
