Establishing Minimal Important Differences for the VR-12 and SANE Scores in Patients Following Treatment of Rotator Cuff Tears

BACKGROUND: Minimal important differences (MIDs) for the Veterans RAND 12-Item Health Survey (VR-12) and the Single Assessment Numeric Evaluation (SANE) have not been reported in patients following treatment for rotator cuff tears (RCTs). PURPOSE: To determine the MIDs for the VR-12 and SANE among patients with RCT after treatment. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHOD: A total of 222 patients diagnosed with RCT completed the VR-12 and SANE at baseline and then received surgical or nonsurgical treatment. After 64 weeks, 160 patients completed the VR-12, the SANE, and a global change questionnaire. We applied a distribution-based approach to estimate the MIDs for the SANE and for the physical component score (PCS) and mental component score (MCS) of the VR-12. We then used the global rating score as an anchor for 20 patients who perceived a minimal improvement, and we applied an anchor-based approach. One-half standard deviation of the baseline score was used in the distribution-based approach. Linear regression analyses and backward model selection were conducted to evaluate the associations between patients’ characteristics and the anchor-based MIDs. RESULTS: The MIDs derived from distribution-based method estimates for the VR-12 PCS, MCS, and SANE scores were 4.94, 5.99, and 11.80, respectively. The MIDs estimated using the anchor-based method for the PCS, MCS, and SANE scores were 2.57 (90% CI, –1.62 to 6.76), 1.87 (90% CI, –2.07 to 5.80), and 27.25 (90% CI, 16.17 to 38.33), respectively. The final regression model for significant predictors of the MID on the PCS included baseline PCS (P < .001), body mass index (P = .014), symptom duration (P = .011), diabetes (P = .009), and surgery (P = .089). The final model for the MID on the MCS included baseline MCS (P < .001), patient sex (P = .027), and diabetes (P = .083). The final model for the MID on SANE included baseline SANE score (P = .059) and diabetes (P = .050). CONCLUSION: This is the first study to assess the MIDs for the VR-12 and SANE scores in patients with rotator cuff disease. The estimates of MID will facilitate the interpretation and application of these outcome measures in clinical practice and research.