This is one of the first studies that assessed self-worth and health related quality of life (HRQoL) using a self- and proxy report in early treated children with CH. The results of the study showed that CH could have a negative impact on several aspects of HRQoL and self-worth. Ten year old children with CH born in 1992–1993 experienced worse HRQoL than the norm population with respect to cognitive -, motor- and social functioning, positive emotions, negative emotions and autonomy. In addition, a greater percentage of children with CH, especially patients with severe CH, appeared to be at risk for impaired HRQoL as well as for impaired self-worth with respect to school performance and athletic performance.
These results are in line with our previous results among young adults with CH, who reported also lower HRQoL and lower self-worth than healthy peers . Two other studies evaluated the HRQoL in young adults with CH [13, 14]. Sato et al. showed that the HRQoL of young adults did not differ from healthy controls . In a recent study of Leger et al. , young adults with CH had a lower HRQoL than their healthy peers, as in our study. These authors underlined the need of early and consequent monitoring patients with CH [. Several other studies showed that children and adolescents with CH were at risk of social-emotional problems, such as behavioral disorders and psychiatric disturbances. Tinelli et al.  found that adolescents (> 12 years) scored significantly higher than controls on withdrawal, anxiety/depression, thought problems, attention problems and aggressive behavior. Bisacchi et al.  found more internalizing and externalizing problems in 6–10 years patients with CH. However, they found no differences between patients and controls in other age groups. The results of our study can be considered in line with a growing body of literature about the psychological and social consequences of medical treatment in children with chronic diseases. Many of these studies concluded that children with a chronic disease show more maladjustment than healthy children [7, 8, 31].
The most persuasive result is that patients with CH reported considerably worse parent- and child-reported HRQoL in the domains “motor functioning” and “cognitive functioning”, also presented in a high percentage of patients considered at risk for impaired HRQoL in these domains. In addition, children with CH appeared to be more at risk for low self-worth in school competence and athletic competence. We also found that lower IQ was associated with lower scores on cognitive functioning and that worse motor skills tended to be associated with worse self-worth regarding athletic competence. These findings are important and require further elaboration. The lower scores on cognitive and motor functioning we found in our study are in line with the outcomes of diverse neuropsychological studies, in which was found that children and young adults with CH scored significantly lower than the norm population on motor functioning [3, 5, 6, 28–30] and had more problems with attention and memory [32–36]. So, the patient’s perception of motor and cognitive functioning, as measured with the TACQoL, equates with objective findings. However, worse IQ and motor skills did not explain the presence of impaired functioning in most other domains of HRQoL and self-worth, as the results of the regression analyses demonstrated. So, we can conclude that patients with CH are at risk for impaired HRQoL and self-worth, independent of their IQ and motor skills. Furthermore, no significant association of severity, intial T4 dose and age at onset of therapy with HRQoL and self-worth was found.
Therefore, it could assume that living with a chronic disease as such and/or the negative consequences of CH despite of its severity, influence functioning in daily life. CH affects the child’s daily life because of the need of regular T4-dose adjustments, the daily T4 administration, frequent T4 and TSH measurements, consciousness of having a chronic disease, and sometimes the need of adjuvant medical care such as speech training and physiotherapy. In addition, the cognitive and motor problems of patients with CH may affect their social life, self-worth and emotional functioning. From this study and our previous studies [3, 9, 37], it is apparent that patients with CH seem to be vulnerable in these areas. Besides, one has to keep in mind that a suboptimal thyroid hormone state may affect well-being. Whereas the goal of long-term T4 treatment is to maintain euthyroidism, this remains challenging because of the continuous need to adapt T4 dose in a growing child and the need of treatment compliance. It has been shown that differences in serum FT4 and TSH concentrations, even within the reference range, may be determinants of psychological well-being in treated hypothyroid patients .
The strength of our study is that we tested a nationwide cohort of patients with CH, all treated by pediatricians who followed national guidelines, and that at psychological assessment, all patients had plasma TSH concentrations within the reference range. Besides, HRQoL was assessed by self-report as well as by the parents of the children with CH. Moreover, we tried to strengthen the clinical meaning of the results, by using percentages at risk of impaired HRQoL and self-worth as outcomes, in addition to mean scale scores. This is considered a suitable way because a golden standard for bad HRQoL and self-worth is lacking.
The limitations of the current study should also be taken into account. First, the loss of subjects from the original cohort restricts the representativeness of the current sample. However, we clarified the etiology of both the excluded patients and the patients not willing to participate (Table 1). Second, we could not use a control group and no information about the socio- economic status of the norm population was available. In general however, Dutch normative data of standardized measures such as the CBSK and TACQoL are sufficient to make adequate comparisons.
Third, caution is called for generalizing our results to children who are nowadays growing up with CH because treatment protocols changed since the 1992–1993. The question is, whether the impaired HRQoL of patients with CH in our study could be assigned to suboptimal treatment years ago, as lower initial T4 dose and older age at onset of therapy compared to the current treatment protocols. In the present we did not found any significant association of initial T4 dose and age at onset of therapy with HRQoL and self-worth, which might be an indication that the contribution of treatment factors to psychosocial outcomes in patients with CH is limited. So, it could be assumed that also children with CH being treated nowadays should be considered at risk of impaired HRQoL and self-worth.
Another shortcoming of the study is that we did not examine other potential risk- and protective factors of HRQoL and self-worth, as socio-economic and psychosocial factors (e.g. parenting, family functioning, coping). Future research should be directed at these factors, in order to be able to detect and support the children and adolescents who are at risk for impaired psychosocial functioning at an early stage. Finally, because of the cognitive and motor problems in patients with CH, it seems important to examine the effect of adjuvant care like physiotherapy, speech training and intervention programs directed at the improvement of cognitive functions.
Conclusion and Clinical implications
This study has shown that children with CH, diagnosed by neonatal screening, are at increased risk for impaired quality of life and self worth. In particular, our findings add to the evidence for motor and cognitive problems in relation to CH. Following this, we can conclude that children with CH are vulnerable and that there is need for specific care. We believe that these results deserve proper attention and awareness of physicians treating these children. Furthermore, patients with CH and their parents should become more aware of the possible negative consequences of growing up with CH. Follow-up of patients with CH should not only be a medical/biochemical evaluation but, also to attain the best achievable quality of life. The focus during the follow-up should shift to attention to school performances, social-emotional functioning and supporting the patients. Therefore routine monitoring HRQoL and social-emotional functioning in children with CH is recommended. Incorporating patient reported outcomes of HRQoL in daily clinical practice will contribute to better communication with health care professionals and makes it easier for them to refer to the needed care if necessary [39, 40]. In addition, the use of valid and reliable screening instruments to detect patients with CH at risk for social, emotional and behavior problems are recommended, for example the Strength and Difficulties Questionnaire (SDQ) . When motor problems are present, patients should be motivated to engage in sport activities or should be referred to the physiotherapist if needed. When cognitive problems are present, psychological examination would be useful and if necessary, intervention programs that improve cognitive functions such as memory and attention functioning or speech training might thereafter be offered to particular individuals. Finally, it seems important to stimulate children’s social performance and to support children with their social skills.