Study design: The development and construction of a specific instrument for measuring quality of life in adolescents with spine deformities was investigated.
Objectives: To assess the validity and reliability of the Quality of Life Profile for Spine Deformities.
Summary of background data: An 88-item questionnaire was self-administered to 174 patients ranging in age from 10 to 20 years with spine deformities. Items were rated on a five-point Likert scale. Higher scores means high level of impairment in quality of life. Age, gender, menarche or voice change, salient symptoms in the medical record, ordinary parameters on physical examination, and measurements on standard anteroposterior and lateral radiographs were recorded. The retest was done 10 days after the initial administration in a subsample of 35 patients.
Methods: The test-retest reliability was analyzed calculating the intraclass correlation coefficient. Internal consistency was measured with the Cronbach's alpha method. Factor analysis was used to obtain a reduced number of variables. Construct validity was assessed using the principal components model of factor analysis based on the correlation matrix and using the varimax computer algorithm for orthogonal rotation. Discriminant validity was assessed using the Kruskal-Wallis test.
Results: The Quality of Life Profile for Spine Deformities contained 21 items and five factors in conceptual terms labeled psychosocial functioning, sleep disturbances, back pain, body image, and back flexibility. The overall questionnaire score showed an internal consistency of 0.88 and a test-retest correlation of 0.91. Patients with structural curves showed significantly higher scores in all dimensions of the Quality of Life Profile for Spine Deformities except for the subscale of body image than patients with postural curves. When patients were grouped according to the symptom of back pain, those with backache had a significantly higher quality of life overalls score and scores in the dimensions of sleep disturbances and pain. Brace-treated patients showed statistically significant differences in the quality of life overall score and scores in the dimensions of psychosocial functioning and back flexibility.
Conclusions: The instrument developed for measuring quality of life in patients with spine deformities during the period of bone growth has validity, internal consistency, and high test-retest reliability. The conceptualization of quality of life of the Quality of Life Profile for Spine Deformity includes psychosocial dimensions and pain and function.