O2127: The Prevalence of Persistent Idiopathic Toe-walking and of Persistent Toe-walking in Children with Autism Spectrum Disorder

Background: Persistent toe-walking (PTW) beyond the first few years of life may be due to idiopathic toe-walking, autism spectrum disorder (ASD), or other neurologic disorders. ASD has also been associated with increased risk of surgery for toe-walking in some studies. The purpose of this study was to ascertain the true prevalence of persistent toe-walking in children with and without ASD, and to determine whether children with ASD have higher odds of toe-walking and surgery for toe-walking than children without ASD.

Methods: All patients ages 3 to 17 who were continuously enrolled members in our health system over a two-year period were identified. Using all relevant International Classification of Disease (ICD) codes, all patients with a diagnosis of toe-walking which persisted beyond age 3 were included and all children with and without ASD were included. Exclusion criteria included all neuromuscular or genetic conditions that may contribute to toe-walking. All Achilles lengthening surgeries were noted, and data on sex, race and body mass index (BMI) percentile was gathered. The prevalence of PTW amongst children with and without ASD was calculated. Chi-square testing and multivariable logistic regression analysis were done to assess for significant differences in odds of toe-walking and progression to surgery.

Results: Of the 284,925 children who met inclusion criteria, 4,622 had persistent toe-walking with an overall prevalence of 1.6%. A total of 7,545 children with ASD were identified; among these children, there were significantly more males (80.2% versus 50.3%, p < 0.0001) and significantly higher mean BMI percentile (64.95% versus 62.59%, p < 0.0001) compared to children without ASD. There was a much higher prevalence of PTW of 6.3% in the group with ASD and 1.5% in the control group (p < 0.0001). Multivariable logistic regression analysis demonstrated that the group with ASD had an increased odds ratio (OR) of PTW of 4.13 (95% CI 3.74 – 4.56, p < 0.0001). Amongst children with PTW and ASD, 4.3% of patients underwent surgery compared to 2.6% of children with persistent toe-walking without ASD (p = 0.041). Children with ASD and PTW did not have a significantly higher OR of progression to surgery compared to children with PTW but without ASD.

Conclusion: This is the largest known study on the true prevalence of PTW in children both with and without ASD, demonstrating a dramatically increased prevalence and risk of PTW in children with ASD. Males and White patients had significantly higher OR of PTW. Children with ASD did not have a higher OR of progression to surgery.