Translation, Validity, and Reliability of the Indonesian Version of the Shoulder Pain and Disability Index (SPADI)

Background: The Shoulder Pain and Disability Index (SPADI) is a widely used 13-item shoulder-specific patient-reported outcome measure for shoulder pain disorders. The English version of SPADI is easy to use and demonstrates excellent measurement properties for clinical and research settings.Purpose: To translate and culturally adapt an Indonesian version of SPADI (SPADI-IDN) and then validate its use in Indonesian patients.Study Design: Cohort study (Diagnosis); Level of evidence, 2.Methods: Through a forward and a backward translation process, the validity of the questionnaire was investigated. The study population was 100 patients with shoulder pain who were treated in a hospital in Indonesia. The patients were asked to fill out the SPADI-IDN during their visit. To evaluate the validity of SPADI-IDN, the patients were also asked to fill out the Medical Outcomes Study 12-Item Short-Form Health Survey and the Oxford Shoulder Score. To assess the test-retest reliability, the same patients were asked to fill out the SPADI-IDN questionnaire again 1 week later. The assessment of construct validity, test-retest reliability, internal consistency, floor and ceiling effect, and measurement of error followed the COSMIN (Consensus-based Standards for the selection of health Measurement Instruments) guidelines. The Bland-Altman method was used to explore absolute agreement.Results: Of the 100 eligible patients, all were used to assess construct validity, and 87 patients (87%) were used to assess test-retest reliability. Almost every established hypothesis about the correlations between SPADI-IDN and other questionnaires could be confirmed, implying good construct validity. No floor or ceiling effects were found. The intraclass correlation value was 0.99, indicating strong test-retest reliability. A Cronbach alpha was 0.95, indicating a good internal consistency. The Bland-Altman analysis did not reveal any bias. The standard error of measurement and the minimal detectable change at the individual and group levels were 2.65, 7.3, and 0.7, respectively.Conclusion: The SPADI-IDN represents a valid and reliable tool for measuring pain and disability in patients with shoulder pain disorders.