Development and content validation of a financial and functional outcomes tool for diabetes-related foot disease in patients undergoing major lower limb amputation: a prospective observational study from Pakistan

ObjectiveTo develop and content validate a questionnaire to assess the financial and functional impact of major lower limb amputation in patients with diabetes-related foot disease.DesignProspective observational study.SettingThis study was conducted at a tertiary care centre in Pakistan.ParticipantsWe conducted a thorough literature review and a group interview with 10 participants, resulting in domain identification and item generation. The group included seven patients with diabetes-related foot disease who underwent major lower limb amputation and three caregivers. Subsequently, a focused group discussion was held to assess overlap and duplication among the items, and two rounds of content validation were carried out by five content and five lay experts in both English and Urdu. Question items with a Content Validity Index (CVI) score of >0.79 were retained, items with a CVI score between 0.70 and 0.79 were revised and items with a CVI score of