This is one of the first studies to describe the health related quality of life (HRQoL) of both children and adults with different muscular dystrophies (MDs) using validated and reliable instruments. The results of the present study indicate that having a MD does negatively influence the HRQoL on several domains, which can be expected because of obvious reasons.
Children (aged 8–11) reported a worse HRQoL on motor functioning and autonomy which can be expected considering the progressive nature of their MD, but they also reported a worse HRQoL on social functioning and emotional functioning as compared to age-related healthy individuals. Especially the latter shows that HRQoL of the patients is affected. The large effect sizes on these two scales underscore the clinical significance of these findings. Surprisingly, both children and adolescents reported a better HRQoL for physical symptoms. Considering the items included on this scale which do not relate to their disease, it may be that children with MD respond emotionally different to such problems than healthy children. Living with their progressive disease possible changed their values, which may be a result of the process of response shift, which has been described in adults with cancer . Response shift implies that the experience with an illness changes the internal standards of patients, resulting in changes in the meaning of their self-evaluation and hence in a possibly different experience of problems.
We did not find cognitive problems for the younger and older children; nor in adults. It is important to notice that children and adolescent do not report more negative emotions compared to their healthy peers. Negative emotions included in the questionnaire are feelings of irritation, or anger. Adult patients, and especially males, however do report negative emotions, e.g. feelings of aggressiveness.
For adult patients HRQoL was lower on several scales as compared to the general population. Pain was reported, only by males, but not associated with type or severity of MD. This finding supports those of Abresch et al  who studied the effect of pain on the QoL of individuals with slowly progressive neuromuscular disease (NMD), including a group of LGMD patients. They found that with the exception of adult spinal muscular atrophy, the frequency and severity of pain reported in slowly progressive NMDs was significant.
Within-group differences were studied for the adult patients. For type of MD we found a more favorable HRQoL for BMD patients. Interindividual disease progression variation in BMD is extensive, and several of these patients were only mildly affected. For severity only minor differences were found, possibly explained by BMD patients. Consequently, some confounding of type of MD and severity should be taken into account.
Results of this study show that patients with more severe disease do not necessarily have a worse HRQoL. Only differences on fine motor and social functioning were found. Apparently, severity is not a factor that significantly influences HRQoL. This is in line with findings of Abresch et al  who also studied factors that influence HRQoL in patients with neuromuscular diseases. They found that level of disability is not a factor that significantly alters life satisfaction. They postulate that this is because physical functioning has been adequately managed by the patients. Comparable findings are reported by Kohler et al. . They report that quality of life is not correlated with physical impairment.
There are a few limitations to this study. Firstly, the study has a relatively small sample size. Secondly, there is probably a selection bias. All patients who participate in this study were participating already in another study. It is most likely that this has positively influenced the response rate. Thirdly, most assessments of the questionnaire were done by phone. It is not clear how this may have influenced the responses. Fourth, only a restricted number of predictors, namely severity and type of muscular dystrophy, could be investigated, and only in the adult patient population. For example, use of medication such as prednisone or other corticosteroids could also influence the HRQoL outcome. More longitudinal research is needed to trace the patients, at risk for adjustment problems. An interesting area of research would be the coping resources patients use, and preferably the research should be conducted administering questionnaires to patients in person and interviewing them. Furthermore, nearly all of the children participating in this study were boys with Duchenne muscular dystrophy. Therefore, the generalizability of this data to children with other forms of MD and to girls does not seem valid.
Overall, it should be acknowledged that the findings for adults only show a few large effect sizes on especially functional domains (gross and fine motor functioning) and for sleeping for females only. Moderate clinical differences are found for aggressiveness, depressive moods and vitality. Communication about such problems in clinical practice should be encouraged to evaluate in which way the patient is troubled. This can be stimulated by computer-scored individually measurement of HRQoL, in order to inform the physician about the patient's HRQoL [24, 25]. The computer output – usually a graphical summary of HRQoL outcomes – assists the physician to focus at the HRQoL domains that correspond with patients needs. Utilizing HRQoL measurement can facilitate patient-physician communication and identifying patients with the greatest needs, so that referring to other health care providers is possible.