Introduction

Asthma is the most common chronic non-communicable disease in children worldwide 1. Asthma prevalence is higher in children in Europe (8.9%), compared to the rest of the world (7.2%)2 but varies between countries 3. Most children with asthma achieve good disease control with maintenance low dose inhaled corticosteroids (ICS), which are effective at preventing most asthma hospitalisations and deaths 4. However, some children remain poorly controlled despite being prescribed high-dose ICS treatment, often due to poor adherence. This contributes to suboptimal asthma control and severe attacks5; 6. Up to half of patients attending tertiary care paediatric asthma clinics are non-adherent (defined as taking less than 80% of their prescribed dose)7.
The Global Initiate for Asthma (GINA) highlights that suboptimal use of asthma treatment is a patient-specific barrier that contributes to the burden of asthma 8. Similarly, the UK National Review of Asthma Deaths reported that 67% of asthma deaths were avoidable, and one of the most important avoidable factors was low ICS adherence in the month and/or year before death 9.
Many interventions have been developed to address the issue of poor ICS adherence in children. A meta-analysis in adults and children identified that interventions for improving adherence in asthma can be effective10. However, the meta-analysis did not examine the intervention characteristics e.g. content, channel of delivery and context of the intervention, which form the three components of behaviour change framework (3CBC11) in relation to intervention efficacy. It is important to be able to identify characteristics of effective interventions so that they may be applied in practice.
Moreover, the reliability of the diagnosis of asthma and the adherence measurement tool have not previously been used to identify high reliability interventions. If patients are diagnosed with asthma incorrectly, non-adherence to a treatment that is therefore unnecessary is logical. Similarly, if adherence is overestimated in studies using unreliable adherence measurements, then the conclusions drawn from the studies will also be inaccurate. By investigating these factors, the data presented in this review are likely to be more relevant to practice as they represent a rigorous test of the intervention.
The National Institute for Clinical Excellence (NICE) has developed guidelines intended to aid the design of adherence support for long term conditions at any stage of the life span 12. The guidelines apply the Perceptions and Practicalities Approach (PAPA13 E-image 1). This approach recognises that adherence varies within the individual, over time and across treatments. Adherence/non-adherence is best understood in terms of the interaction between an individual and a particular treatment. It is a variable behaviour rather than a trait characteristic. The Perceptions and Practicalities Approach (PAPA) conceptualises adherence as including both intentional and unintentional non-adherence.
The application of the PAPA approach to adherence interventions has the following key features firstly, the need for a no-blame approach as patients are often reluctant to admit to non-adherence, or to concerns about the treatment, as they fear that this may be interpreted by the clinician as doubting their expertise. Hence, non-adherence and the reasons for it are often hidden. The second key feature is the need to tailor support to address both perceptions (e.g. beliefs about asthma and its treatment) and practicalities (e.g. clear instructions on inhaler technique, establishing a medication routine). Both perceptions and practicalities influence the patient’s motivation and ability to start and continue taking the treatment. Indeed, research in asthma has shown beliefs about ICS are often important perceptual barriers to adherence, particularly doubts about the personal need for regular inhaler use particularly in the absence of symptoms and concerns about corticosteroids 14; 15.
This systematic review aims to address these research gaps by 1. Specifically examining adherence in children with asthma 2. Using quality indicators to identify those studies that may be more informative, and3. Examining the characteristics of adherence interventions to identify features that may be relevant to practice.