Measurement and interpretation of social distress using the social difficulties inventory (SDI)

Cancer has a significant social impact. There is a requirement to undertake formal assessment of this in research and clinical practice. Aim: To establish values of clinically meaningful differences and changes in social distress (SOCD) using the social difficulties inventory (SDI). Methods: Newly diagnosed patients treated with curative intent completed the SDI and the EORTC quality of life questionnaire (EORTC QLQ-C30) at baseline, 6, 12 and 24 months. Minimally important differences (MIDs) were estimated using anchor and distribution methods. Results: One hundred and eighty-eight patients participated. SOCD was elevated at baseline demonstrating the social burden of cancer on patients following diagnosis. Anchor estimates for MIDs were by age groups 3.37 and in comparison to EORTC QLQ-C30 social functioning scale from 0 to 6.27. Using distribution methods: SEM 2.01-4.92 and SD 1.67-3.57. Conclusion: For general guidance, an estimate of 3 (range 0-44) is recommended as a clinically important difference, illustrated by case studies and group comparisons. (C) 2008 Elsevier Ltd. All rights reserved.