Initial Adherence to Prescribed Brace Wear for Adolescent Idiopathic Scoliosis Predicts Future Brace Wear and Curve Improvement

Background: Adolescent idiopathic scoliosis (AIS) is a common spine condition in children with a prevalence of 0.47% to 5.20%. Although some scoliosis curves require surgical intervention, many are managed non-operatively using treatments like bracing. The effectiveness of bracing to slow curve progression is correlated with brace wear time. Non-adherence to prescribed brace wear is a common limiting factor of bracing, especially since it is difficult to predict. Early prediction and identification of future non-adherers may permit supportive interventional strategies to prevent curve progression to the surgical level.

Methods: Consecutive AIS patients prescribed a scoliosis brace at our institution from January 2015 to September 2019 were reviewed. Inclusion criteria were the age at first brace fit (10-17 years old), an AIS diagnosis, and prescription of a brace for 10-18 hours daily. Bracing patients underwent an initial one month wean-in period where they gradually increased their brace wear until the final week - Stage 3 - where they were instructed to wear their brace greater than 80% of their prescribed daily amount. Patients who obeyed the rules at Stage 3 were considered “adherent.” We hypothesized that adherent patients would wear their brace more at the six and 12-month post brace-fitting appointments, and would reflect more curve improvement secondary to the increased adherence. Brace wear was recorded by an imbedded thermosensor and assessed four to six weeks (end of wean-in period), six months, and 12 months after brace fitting. Statistical analysis included Fisher’s exact tests, t-tests and logistic regression providing odds ratios with confidence intervals (CI).

Results: Sixty-three AIS bracing patients (mean±sd age 12.6±1.3 years) were included, of which the majority were female (85.7%, n=54). Thirty-eight (60%) patients were adherent at the end of the wean-in period, and the adherent group wore their brace on average eight hours more per day at this point (p < 0.001). Adherent patients had a significant increase in brace wear time and adherence compared to the non-adherent group at the six-month (p < 0.001) and 12-month visits (p < 0.001) (Table 1). Compared to the non-adherent patients, the odds of future adherence were 11.4 (95% CI 3.4, 37.7) times greater for adherent patients at the six-month, and 5.6 (95% CI 1.8, 16.9) times greater at the 12-month appointment - this trend is illustrated in Figure 1. Initially adherent patients also had more scoliosis reduction, on average, at the 12 month visit than non-adherent patients (p = 0.019) (Table 1).

Conclusion: Initial adherence to AIS brace wear during the wean-in period is associated with future adherence to brace wear and curve improvement. If a patient is non-adherent during the wean-in period, supportive interventions should be considered, or a different treatment plan may be necessary to prevent curve progression to the surgical level.