A study of the intertemporal consistency in the diagnosis of autism spectrum disorder

Abstract

Objective To understand the cross-time diagnosis stability of autism spectrum disorder (ASD), and analyze the situation of misdiagnosis and missed diagnosis. Methods A retrospective analysis was carried out to analyze 3 163 children who were first time diagnosed as ASD in Shenzhen Maternal and Child Health Care Hospital from January 2014 to September 2018. 463 cases of ASD were evaluated again after one year apart. Statistical methods such as rank sum test or chi-square test were used to compare the coincidence rate, misdiagnosis rate and missed diagnosis rate among different age groups. Misdiagnosis was analyzed among different age groups. Results The mean age of the first diagnosis was 39.00 (29.04, 56.04) months, and the mean age of second diagnosis was 54.07 (43.83, 69.03) months. The interval time between the two diagnoses was 17.78 (14.33, 24.94) months. The diagnosis coincidence rate of ASD was 86.96%, the misdiagnosis rate was 5.80%, and the missed diagnosis rate was 7.25%. The misdiagnosis rates of 72-month-old group were higher than that of 24-month-old group and 36-month-old group (χ2=8.316, P=0.040). There was no difference in missed diagnosis rate between each group (χ2=1.358, P=0.715). 28 children were misdiagnosed, 72-month-old group. While>72-month-old group was liable to misdiagnosis as Attention Deficit Hyperactivity Disorder (ADHD) or emotional disorder than these two group (P=0.009). 35 children were missed diagnosis, 72-month-old group because of developmental problem,while >72-month-old group was liable to missed diagnosis because of ADHD or emotional disorder (P=0.008). Conclusion The diagnostic consistency of ASD with the interval period of 17.78 months, including the initial diagnosis in children younger than 1 year old, is pretty high. ASD is liable to be confused with other developmental disorders at the younger age. When order than 72 months-old, ASD is liable to be confused with ADHD or emotional disorders. Key words: Autistic disorder; diagnosis; Age