By Robert Linnehan
Researchers found, when combined with data from previous reports, the minimum clinically important difference in Scoliosis Research Society-22R domains could be estimated as 0.4 after adult deformity surgery. According to researchers, the minimum clinically important difference (MCID) is commonly determined to find a threshold of improvement that will be relevant to a patient. The purpose of the study was to find the MCID for Scoliosis Research Society-22R (SRS-22R) domains in patients with adult spinal deformities, as well as to compare the results with data from previously published studies.
The study comprised a total of 1,321 patients. The researchers used patients’ postoperative answers to the last eight questions of the SRS-30 questionnaire as anchors to determine the MCID for appearance, activity and pain domains, subscore and total score through the use of a receiver-operating-characteristic curve analysis. Distribution-based methods were also used to calculate MCID. 
Results showed an improvement in the mean SRS-22R appearance score, from 2.5 preoperatively to 3.62 at 1-year postoperatively. Improvements were also seen from baseline to 1-year postoperatively in mean SRS-22R activity score (2.96 vs. 3.33) and mean SRS-22R pain score (2.73 vs. 3.6), according to the researchers. Additionally, the researchers calculated an improvement in mean total score from 2.93 preoperatively to 3.65 postoperatively.
According to the researchers, a statistically significant difference was observed between domain scores for patients’ responses to the anchors. Using different calculation methods, theresearchers determined MCID values of 0.23 to 0.60 for activity and 0.24 to 0.57 for pain. Using the same methods, the MCID values were 0.19 to 1.23 for appearance, 0.16 to 0.43 for subscore and 0.17 to 0.71 for total score.
The researchers concluded the MCID for SRS-22R was 0.4 for adult spinal deformity patients, which corresponds to a change of one interval in two of the five questions for a single domain.