Do demographics and comorbidities act as predictors of co-diagnosis of attentiondeficit/hyperactivity disorder in autism spectrum disorder?

Abstract

Objective The study aims to determine the demographic predictors of attention-deficit/hyperactivity disorder (ADHD) in hospitalized children with autism spectrum disorder (ASD) and the impact of comorbidities on the length of stay (LOS). Methods A retrospective study was performed using a nationwide inpatient sample from US hospitals. All patients were < 18 years in age with a primary diagnosis of ASD (n = 3,095) and grouped by co-diagnosis of ADHD based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) diagnosis codes. Logistic regression was used to calculate the odds ratio (OR) and linear regression for estimated LOS. Results Male patients had a higher odds of comorbid ADHD (OR: 2.2). Age and race were not significant predictors of ADHD though the condition was found to be prevalent in adolescents and Caucasians. These children were mainly from the South (30.8%) and the Midwest (29.9%) regions of the US. Psychosis was seen in 37.3% of patients with ADHD and was more likely to be comorbid psychosis (OR: 1.8). Depression and ADHD increased the LOS in hospitals for ASD by 2.1 days and 0.9 days, respectively. Conclusion Our study led us to determine the demographic predictors of comorbid ADHD in patients with autism, and we believe that our findings can help to better serve these patients and their families. Comorbid ADHD and depression can prolong the length of hospitalization and they necessitate the need for acute inpatient care in such patients.