Discussion
Summary of the Evidence
This is the first review to summarise effective interventions to
increase adherence in children with asthma, taking into account the
reliability of the studies and the behaviour change framework and
techniques used in a clinically meaningful way. Previous reviews of
adherence interventions in adults and children have shown that only half
of interventions are effective at increasing adherence10. Similarly, we found that only nearly half of the
included studies (11/25) were effective at significantly increasing
adherence 23-25; 32-34; 36-38; 41; 44. We then
explored the crucial factors for an effective intervention to increase
adherence.
Of the thirteen studies that were effective, nine were considered highly
reliably 23; 24; 32-34; 36-38; 41. By comparing the
effective and reliable studies (9/25) (accurate asthma diagnosis,
objective adherence measure and low/moderate RoB) to the unreliable or
ineffective studies this review should inform the development of future
interventions. In terms of context high reliability interventions
carried out in the UK (2/25) and New Zealand (2/25) were most likely to
be effective. High reliability Interventions carried out in the USA were
most often ineffective (6/25 versus 1/25 that was effective). However,
regarding healthcare context there were no differences between different
healthcare settings such as primary or secondary care. Three of the four
high reliability but ineffective studies were not tailored to the
patient group 21; 39; 47. This highlights the
importance of tailoring as it has been well reported that tailoring is
associated with more effective interventions 12.
The findings of this review support the use of technology as a channel
to deliver the adherence intervention including electronic monitoring
devices for measuring adherence and patient and health-care provider
apps and telephone calls. Healthcare practitioner type is not as
important as face-to-face contact while providing digital interventions.
This finding supports a previous recent review based on digital
interventions in long-term conditions 48. Those
planning an adherence intervention should therefore consider the amount
of contact alongside digital interventions as a key component to future
effectiveness.
In terms of content, six out of the nine reliable effective
interventions were coded as Level 3 PAPA 24; 32; 33;
36; 38; 41. Three high reliability and effective studies did not meet
the criteria for Level 3 PAPA 23; 34; 37. Overall,
only two of the highly reliable studies based on Level 3 PAPA did not
result in effective interventions 26; 35. The two
studies had moderate risk of bias and did not involved face-to-face
contact with a healthcare professional.
PAPA is easy to apply when developing an intervention as it simply
highlights the effective minimal ingredients for change in
adherence49. This review found that currently
developed interventions in this area largely neglect the role played by
patient beliefs about asthma and ICS. Research shows that these are
often important determinants of non-adherence in adults50; 51 and there is immerging evidence of relevance in
children 52: in terms of parental 53;
54 and adolescent beliefs 14; 15. Patient’s
perceptions that are of particular importance are beliefs about their
personal need for treatment (even in the absence of symptoms) and
concerns about steroid safety. These issues are important because
necessity and concern beliefs may be the drivers of adherence as they
influence motivation to adhere to treatment 55; 56.
The most common BCTs used in effective interventions were prompts/cues
(e.g. reminders), feedback and monitoring; pharmacological support and
instruction of how to perform a behaviour. Each BCT was found to be most
effective as part of complex interventions when tailored to the patient.
It is currently unknown how many and what combination of BCTs are likely
to increase the effectiveness of an intervention. However, this review
is the first to show that particular BCTs are important to consider when
developing a tailored intervention for increasing adherence in children
with asthma.
Strengths and
Limitations
Due to the heterogeneity of the adherence outcomes, limited availability
of raw data and a small number of eligible studies a meta-analysis was
not possible within this review.
This systematic review focuses on adherence as an outcome as opposed to
clinical health outcomes as unlike within the adult literature, few
studies in paediatric asthma include both adherence and clinical
outcomes. Focusing on adherence therefore allowed a greater number of
studies to be synthesised. Ideally intervention studies should have an
objective reliable clinical outcome as well as an adherence outcome to
account for potential patient manipulation of the adherence measurement
and for those patients that may have low adherence despite good control
(likely over-medicated). However, unlike in some other conditions,
adherence to ICS has been shown to be highly correlated with objective
clinical outcomes 57 and therefore the use of
adherence as a primary focus for this review is a reasonable proxy.
Most of the interventions had a moderate RoB which was increased by the
high level of performance bias which is common in behavioural
interventions. This is due to the lack of ability to blind patients and
personnel to the purpose of the study, however, many of the studies
tried to counteract that using deception (where ethically permitted).
This included objective electronic monitoring devices also for control
groups and additional measurements to distract from the adherence data
collection. The studies often had low selection bias (for random
sequence generation); detection bias and reporting bias; However,
attrition bias and allocation concealment was frequently unclear with
modern recommended reporting guidelines such as CONSORT58 not being followed. We recommend using objective
methods of measuring adherence and also more than one method of
measurement, and also for the diagnosis of asthma, alongside blinding to
increase the reliability of future intervention findings.
One further limitation is not excluding interventions where the
diagnosis of asthma reported was not rigorous, for example where primary
care medical records were used to identify those with asthma despite no
record of prescribing ICS or where a physician diagnosis was given
without objective measurement of asthma59. Future
intervention studies should ensure the children recruited have a
reliable diagnosis of asthma and objective measurements of adherence so
the true effectiveness of the interventions can be determined60. Therefore, this review considered the reliability
of the evidence for both the diagnosis of asthma, the measurement of
adherence and the risk of bias of the studies.
Conclusions
Adherence interventions in children with asthma have mixed
effectiveness. Effective studies tended to be of higher quality,
targeted both perceptual and practical adherence barriers in a tailored
manner, and used a combination of BCTs. However, due to the small number
of included studies and varying study design quality, conclusions drawn
here are preliminary.
None of the studies have explicitly addressed ICS necessity and concern
beliefs. This remains a potential area of investigation as a method for
enhancing adherence. Future interventions could consider a closer use of
the NICE guidelines including addressing patient’s beliefs and the
channel by which the intervention is delivered; the increasing use of
EMD with feedback delivered in a no-blame collaborative consultation.
Future research is needed to test a PAPA-based intervention with a
rigorous study design as outlined in this review.