Clinical effectiveness of school screening for adolescent idiopathic scoliosis: a large population-based retrospective cohort study

Abstract

SUMMARY: The diversely reported clinical effectiveness of school scoliosis has called for the need of large studies with sufficient follow-up of children. Based on a large cohort of children who participated in the Hong Kong scoliosis screening program and were followed until the age of 19, the program appears to be sensitive and predictive for screening AIS patients with only a low referral rate for radiography. Screening should thus be continued in order to facilitate early administration of conservative treatments. INTRODUCTION: School screening for adolescent idiopathic scoliosis (AIS) has been criticized as resulting in over-referrals for radiography and having low predictive values. Indeed, all but one previous retrospective cohort studies had no follow-up assessments of students until their skeletal maturity, leaving any late-developed curves undetected. The one study that completed this follow-up was well conducted but had low precisions due to its small sample size. Therefore, we aimed to evaluate the clinical effectiveness of school scoliosis screening using a large and long-term-followed cohort of students in Hong Kong. METHODS: A retrospective cohort study was performed on a total of 157,444 students who were eligible for a biennial scoliosis screening, and their screening results and medical records up to 19 years of age were available. Screening tests included a forward bending test (FBT), angle of trunk rotation (ATR), and moire topography for those who showed signs of AIS. Students with an ATR ≥ 15°, ≥2 moire lines, or significant clinical signs were referred for radiography and had their Cobb angle measured. RESULTS: Of the 115,190 screened students in the cohort, 3,228 (2.8%, 95% CI = 2.7% to 2.9%) were referred for radiography. At the final follow-up, the positive predictive values were 43.6% (41.8% to 45.3%) for a Cobb angle ≥20° and 9.4% (8.4% to 10.5%) for needing treatment, while the sensitivities were 88.1% (86.4% to 89.6%) and 80.0% (75.6% to 83.9%), respectively. CONCLUSION: This study demonstrated that school scoliosis screening in Hong Kong is predictive and sensitive with a low referral rate. Screening should thus be continued in order to facilitate early administration of conservative treatments. SIGNIFICANCE: This was the largest study that responds to the need of large, retrospective cohort studies with sufficient followup to properly assess the clinical effectiveness of school scoliosis screening.