The Spider; A Multisystemic Symptom Impact Tool for People with Hypermobility-Related Disorders. Initial Validation in Adolescents

The multisystemic comorbid symptoms/conditions of hypermobility spectrum disorders (HSD) and hypermobile Ehlers-Danlos syndrome (hEDS) often significantly affect daily life. Many of these symptoms are under-recognised during diagnosis and treatment, therefore a comprehensive questionnaire was developed to evaluate their presence and impact. The Spider's eight domains assess neuromusculoskeletal, pain, fatigue, cardiac dysautonomia, urogenital, gastrointestinal, anxiety, and depression symptoms. This paper aims to evaluate the construct validity of the Spider in adolescents. This cross-sectional study recruited international participants through three patient charities and a hypermobility unit. Adolescents aged 13-18, with and without HSD/hEDS. Validated and frequently used comparator questionnaires were used to establish convergent validity. Participants answered each Spider domain and the respective comparator via four online surveys. Convergent validity was assessed by comparing Spider domain and comparator scores through correlational analysis. Known-group validity was assessed by comparing Spider domain scores of hypermobile and control groups using Mann-Whitney U analysis. 1154 adolescents participated, 1036 with HSD/hEDS and 118 controls. Six domains (pain, fatigue, depression, cardiac dysautonomia, gastrointestinal and neuromusculoskeletal) demonstrated strong correlations (r=-0·7 to 0·8) with the respective comparator. The urogenital and anxiety domains showed moderate correlations (r=0·6). All correlations reached statistical significance (p<0·001). Known-group validity was demonstrated in seven domains (p<0·001). The urogenital domain did not show a significant difference between the groups (p=0·094). The Spider domains demonstrate acceptable convergent validity. The Spider questionnaire can accurately, rapidly and concisely measure the impact of common multisystemic comorbid symptoms/conditions associated with HSD/hEDS to help direct care in adolescents.