Overweight is not predictive of bracing failure in adolescent idiopathic scoliosis: results from a retrospective cohort study

Purpose Overweight was found to be a negative predictor of brace effectiveness for adolescent idiopathic scoliosis (AIS), with a threefold higher risk of progression than in normal weight patients. The aim of this study is to investigate overweight, as a predictor of brace results in AIS patients. Methods Design: retrospective cohort study. Population: 351 AIS patients (306 females), mean age 12.9 +/- 1.4, mean Cobb 35.6 +/- 11.4A degrees, mean ATR 11 +/- 4.3A degrees, BMI 19.7 +/- 3, median Risser: 2. Inclusion criteria: no previous treatment, full-time prescription of brace at first visit (18-23 h per day), scoliosis physiotherapeutic exercise according to the SEAS protocol associated. Outcome: improved, progressed, and stable according to the 5A degrees Cobb agreed threshold. Statistics: a stepwise linear regression was used to look for the effect of BMI as a predictor of result. A Chi-square test and logistic regression were used for the overweight category (BMI >= 85th percentile). Control for possible confounders was applied. Results BMI is poorly correlated with final results. Confounders' adjustment did not change the correlation, and the predictive model explained about 10% of the result. Brace results were not statistically different in overweight and normal weight: 44 vs 52% improved, 52 vs 41% stable, and 3 vs 7% worsened, respectively. Conclusions Brace results were similar in overweight and normal weight subjects. These findings subvert the previous results and disprove the role of overweight as a negative predictor. Treatment management, brace type and effectiveness may play a major role in reducing the risks of scoliosis progression.