eCross-cultural adaptation of the spine oncology-specific SOSGOQ2.0 questionnaire to German language and the assessment of its validity and reliability in the clinical setting

Abstract

Background: The recently developed Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ2.0) was proven a valid and reliable instrument measuring health-related quality of life (HRQOL) for patients with spinal malignancies. A German version was not available. Objective: A cross-cultural adaptation of the SOSGOQ2.0 to the German language and its multicenter evaluation. Methods: In a multistep process, a cross-cultural adaptation of the SOSGOQ2.0 was conducted. Subsequently, a multicenter, prospective observational cohort study was initiated to assess the reliability and validity of the German adaptation. To assess external construct validity of the cross-cultural adapted questionnaire, a comparison to the established questionnaire QLQ-C30 from the European Organisation for Research and Treatment of Cancer was conducted. Mean-difference plots were used to measure the agreement between the questionnaires in total score and by domain (deviation from mean up to 10% allowed). Further reliability and validity tests were carried out. Change to baseline was analysed 3–16 weeks later after different interventions occurred. Clinically relevant thresholds in comparison to the EORTC QLQ-C30 questionnaire were evaluated by ROC curve analysis. Results: We could enroll 113 patients from four different university hospitals (58 females, 55 males). Mean age was 64.11 years (sd 11.9). 80 patients had an ECOG performance status of 2 or higher at baseline. External construct validity in comparison to the EORTC QLQ-C30 questionnaire in total score and by domain was confirmed (range of deviation 4.4 to 9.0%). Good responsiveness for the domains Physical Functioning (P