Objectives: The concept “Minimal Important Difference” (MID) is the smallest and most noticeable and meaningful change in the quantitative measurement of quality of life (QoL). Must surgical QoL research has centered on differences in summary statistics. Little has been done to determine the clinical meaningfulness of these differences. This study hoped to determine the MID in patients undergoing antireflux surgery (ARS) for gastroesophageal reflux disease (GERD).
Methods: 300 patients undergoing ARS preoperatively and postoperatively completed the SF-36, a generic QoL instrument (8 domains, best score100, worst 0) and the GERD-HRQL, a symptom severity instrument (best score 0, worst 50). Postoperatively, patients were then grouped by satisfaction level. The changes in score preoperatively to postoperatively were assessed. Statistical analysis was done using Students’ t-test.
Results: Postoperatively, 261 were satisfied, 4 were neutral, and 25 dissatisfied. The neutral patients were grouped with the dissatisfied patients for statistical analysis. The mean change in score for each domain of the SF-36 of satisfied and dissatisfied patients, respectively, were physical functioning 15 vs. -12, role-physical 6 vs. -21, role-emotional 0 vs. -27, bodily pain 31 vs. -4, vitality 3 vs. -17, mental health 6 vs. -12, social functioning 22 vs. -14, general health 11 vs. -5, all p<0.05. For the GERD-HRQL, change in satisfied and dissatisfied patients, respectively, was 26 vs. 10, p<0.05.
Conclusions: For ARS for GERD, the MID as measured by the SF-36 are positive scores. For the GERD-HRQL, the symptom severity score must improve by >10 to be associated with patient satisfaction.