Evaluation of the internal and external responsiveness of Short Form-12 Health Survey version 2 (SF-12v2) in patients with type 2 diabetes mellitus

Purpose The evidence on the responsiveness of the Short Form-12 Health Survey version 2 (SF-12v2) in patients with type 2 diabetes mellitus (T2DM) is limited. The aim of this study was to examine both the internal and external responsiveness of the SF-12 measures in Chinese patients with T2DM. Methods A prospective longitudinal observational study was conducted on 1443 T2DM patients managed in public primary care clinics between 2012 and 2013. These patients were surveyed at baseline and at 12 months using SF-12v2. The internal responsiveness was evaluated by linear mixed effect models. Meanwhile, the external responsiveness was tested by multiple linear regression models and receiver operating characteristic (ROC) curve analysis. Results The internal responsiveness of the SF-12v2 to detect negative change was satisfactory among T2DM patients in worsened group, but only the general health domain of SF-12v2 could detect positive change among T2DM patients with improved group. For external responsiveness, the SF-12v2 detected a significant difference-in-difference between patients with worsened and stable/improved group, but not between patients with stable and improved group. The areas under the ROC curve for all domains and summary scales of the SF-12v2 were not statistically different from 0.7. Conclusion This study showed that the responsiveness of SF-12v2 might not achieve the standard. Despite the wide use of the SF-12v2, we would like to urge that both clinicians and researchers should use it with caution in longitudinal study.