High inhaled corticosteroids adherence in childhood asthma: the role of medication beliefs

RESULTS

Out of a total of 137 consecutive eligible patients, 103 children (75%) entered the study after informed consent was obtained, and 93 children (90% of those enrolled) completed the 3 month follow-up (fig. 1). Most parents who did not participate in or withdrew their child from the study did so because of serious illness in a family member or other pressing circumstances. Clinical characteristics of participating and non-participating children were comparable (table 1). Most participating children had well controlled asthma while on ICS maintenance therapy. Reliable and reproducible lung function results could be recorded in 66 (71%) children, and sensitisation to inhalant allergens was available for 86 children (table 1).

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Figure 1–

Inclusion of patients.

The frequency distribution of adherence to daily ICS is presented in figure 2. Median (interquartile range (IQR)) adherence was 92 (76–97)%. 67 (72%) children had good adherence (>80% of prescribed dosages); adherence rates <60% were recorded in only eight (9%) children (fig. 2). There was a small, non-significant decrease in adherence from the first to the third month of follow-up (median (IQR) -1 (-8–1)%; p=0.483). Adherence rates were comparable between children aged 2–4 yrs (median 92%) and children aged 5–6 yrs (median 92%, p=0.899).

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Figure 2–

Adherence to inhaled corticosteroids measured by electronic loggers.

The association of adherence to the individual item responses on each questionnaire is presented in the online supplementary material. Parental perceptions about illness were not associated with adherence, but perceptions about medications were. Parents who believed that ICS maintenance treatment is needed for their child's health, those who viewed ICS administration as convenient, and those who expected little harm from medicines in general had higher adherence rates to ICS (table 2). The other putative determinants that showed significant (p<0.05) or near-significant (p<0.1) association to adherence are presented in table 3. Not unexpectedly, parental self-reported adherence (as assessed by MARS) was strongly related to electronically measured adherence. In addition, good asthma control was positively related to adherence measured electronically. Parental characteristics such as educational level, asthma knowledge and smoking habits were not significantly associated with adherence (see online supplementary material for details).

For 84 (93%) parents, BMQ scores indicated that the perceived necessity outweighed concerns about ICS (table 4). This was mainly due to the large majority of parents expressing the view that giving ICS to their child would benefit his/her health, even when they had concerns about the use of ICS. The results from other questionnaires were consistent with this finding (see online supplementary material for details). For example, only three parents responded negatively to the TSQM question “Overall, how confident are you that taking this medication is a good thing for your child?”.

DISCUSSION

This study shows that high adherence to daily maintenance treatment with ICS along with good asthma control can be achieved in preschool children with asthma and that high adherence is associated with parental beliefs about the necessity of ICS therapy. The median adherence rate in our study remained stable over 3 months of follow-up at 92%, which is considerably higher than in earlier studies (adherence ranging from 44% to 72%, decreasing strongly over time). For example, a recent study showed that adherence to an ICS prescribed after an emergency visit for acute asthma deteriorated from 90% to 50% during the first 2 weeks after the acute asthma attack [22]. This confirmed earlier population-based observations that most patients with asthma fail to continue ICS use after an initial prescription [23]. Although some large studies showed lower adherence rates for adolescents than for school- and preschool-aged children, age is not consistently related to treatment adherence [1]. Even in pre-adolescent children, adherence to ICS of >75% of prescribed dosages has rarely been described, neither in observational, nor in intervention studies [14]. We emphasise that the very high adherence we observed was not the result of an intervention aimed at improving adherence, but was obtained during routine care in our paediatric asthma outpatient clinic.

The large majority of parents of the preschool children with asthma in our study expressed the belief that ICS therapy for their child's asthma was both useful and necessary (table 4]). This is in contrast with previous studies examining medication beliefs in asthma. Studies in adults with asthma have shown lower BMQ “need” scores and higher “concern” scores [11, 24]. In a study of 622 parents of children with asthma in the USA, concern scores exceeded need scores in 17% of parents, compared to only 4% in our study [15]. Such concerns about the daily use and safety of ICS in children are a major reason for parents to withdraw this medication in their children [25]. Because the distributions of ICS adherence (fig. 2) and parental medication perceptions (table 4]) were strongly skewed towards high adherence and ICS necessity, with relatively little variance, the power of our study to identify determinants for adherence was lower than expected. This may help to explain why we only identified a few parental perceptions significantly associated with adherence rates, and why these associations were relatively weak (tables 2] and 3]).

We found a significant association between ICS adherence and asthma control, with poorer asthma control in patients with lower adherence, suggesting that this association does not only play a role at the severe end of the asthma spectrum, but also in patients with relatively well controlled asthma, and that every effort to optimise adherence to ICS maintenance therapy is worthwhile.

It is interesting to explore potential reasons why the parental medication beliefs and the high adherence rates in our study population differed from those previously reported. Selective enrolment of parents with high need and low concern scores should be considered. However, we feel that this is unlikely, because consecutive outpatients at our clinic were approached for the study, the large majority of whom were enrolled (fig. 1). Furthermore, the high need scores for ICS in this study are in agreement with a previous qualitative study from our clinic, in which parents accepted that their child needed ICS to control asthma, although parents universally expressed reservations about having to give daily medication to their child. Parents whose children were treated in primary care, however, expressed beliefs of the high concern–low need pattern. These findings prompted us to hypothesise that parental medication beliefs can be modified by repeated tailored education and close follow-up in a specialised asthma clinic, resulting in high adherence [26].

The young age of the children in our study may have increased the likelihood of good adherence, because most medication in this age range is given by the parents. However, previous studies have shown poor adherence rates to inhaled medication in young children with asthma, even when parents knew that adherence was being monitored [14]. Therefore, parental awareness of monitoring adherence does not seem a likely cause of the high adherence rates observed. This is supported by the finding that adherence rates did not deteriorate significantly over time in our study. Further follow-up of this cohort will allow us to examine whether the high adherence rates observed can be maintained over longer periods of time.

It should also be noted that access to healthcare and ICS medication is available to all Dutch citizens, because health insurance is mandatory in the Netherlands. Studies in urban US populations have shown that poor insurance and financial issues may play a major role in poor adherence in such populations [1, 6]. Although it is conceivable that excellent insurance coverage may have improved adherence in our study, poor adherence has been shown in earlier Dutch studies of asthmatic children, suggesting that this is not a major determinant [4, 26].

In the absence of other logical explanations for the high adherence and constructive parental medication beliefs observed, we hypothesise that the organisation of our asthma care may be a contributing factor. The fact that our clinic is run by paediatric asthma specialists may be of importance in this respect. Previous studies have shown superior asthma control, better lung function and higher adherence to treatment and self-management plans when asthma care was provided by specialist physicians (paediatric allergists or paediatric pulmonologists, depending on country and setting) compared with general paediatricians or family physicians [3, 27, 28]. A recent systematic review showed that more intensive follow-up, with multiple educational sessions using combinations of instructional modalities, was associated with higher adherence and improved outcomes for children with asthma [3]. In our clinic, such a comprehensive asthma management consists of frequent follow-up visits to both asthma specialist physicians and dedicated asthma nurses, providing repeated tailored education to parents and patients and extensively training and checking correct inhalation technique [16]. In earlier studies, we reported the added value of easy accessibility of asthma nurses which was highly appreciated by parents of children with asthma [26, 29]. This was recently confirmed in a study from a referral centre for children with difficult-to-treat asthma, where the important role of nurse-led home visits to address parental perceptions, contextual and psychosocial issues was highlighted [30]. Taken together, these results suggest that intensive multidisciplinary education about self-management, along with close follow-up in a specialised clinic setting, helps to improve adherence to ICS in children with asthma, with parental perceptions about medication being an important mediator.

It should be stressed, however, that a causal relationship between our model of care and the high adherence we observed cannot be established based on our data because this was an observational study. Ideally, a randomised controlled trial should be performed to test the hypothesis that comprehensive asthma management and close follow-up, as described, leads to high adherence to maintenance medication. However, it has been argued that randomised trials on the effects of complex interventions, such as our model of asthma management, are fraught with difficulties [16]. A prospective study in which both adherence and parental perceptions about medicines are followed-up over longer periods of time from the time of referral to a specialised asthma clinic would also be worthwhile.