14781-koppen

241 Treatment adherence 11 are based on a child’s symptoms (e.g. lowering the dose if a child has frequent loose stools). For the regression analyses, the MARS-5 score was considered as a continuous variable instead of a dichotomized variable to overcome this problem. A few other limitations should be taken into account when interpreting these results. Although the overall response rate in our study was 84%, which is considered good for this type of study, not all invited families agreed to participate which may have resulted in selection bias. It seems intuitive to assume that nonadherent families may have been more prone to refuse participation or agree to participate but not return the questionnaires. Moreover, our study results may be at risk of desirability bias, with participants providing answers that are socially desirable. Another limitation of this study was that we did not take symptomatic response to treatment into account. In a future study, it would be interesting to longitudinally monitor patients from their first visit until 6 or 12 months of treatment, to assess the association between treatment efficacy and treatment adherence. In conclusion, proxy-reported treatment nonadherence to polyethylene glycol treatment in children with FC is common. Treatment inconvenience, dissatisfaction with treatment and the emotional impact of FC may negatively influence treatment adherence. These factors should be taken into account in the clinical care of children with FC, especially if they do not respond well to prescribed treatment.