Introduction

Fragile X Syndrome (FXS) is the most common heritable cause of autism and intellectual disability. Autism Spectrum Disorder (ASD) is characterized by social interaction and communication impairment. Individuals with FXS and ASD have greater prevalence of seizures, persistence of sleep problems, and increased behavior problems.

Objective Examine inpatient resource utilization in FXS-diagnosed patients with and without ASD.

Methods

Healthcare Cost and Utilization Project Nationwide Inpatient Sample (2016-2019) data were used to assess encounters aged 1+ years old having ICD-10-CM diagnosis of FXS. Length of stay (LOS), in-hospital mortality and cost-to-charge ratio adjusted charges (costs) were stratified by ASD and compared using chi-square and t-tests. Sampling-weighted logistic regression analyses were used to estimate ASD impact on mortality while hierarchical models were used for LOS and .

Results

The nationally-weighted sample included 6,235 encounters with median (IQR) age of 20 (11-36) years for those with FXS-ASD and 37 (28-59) years for those without ASD. Admissions with FXS-ASD were more likely to be male patients (85.9% vs 49.7%, p<.0001). Medicaid coverage was more common among admissions with FXS-ASD (43.7% vs 25.4%; p<0.001). FSX-ASD admissions were more likely to include neurologic and neuromuscular chronic conditions (28.1% vs 15.8%, p<0.001) but less likely to include chronic cardiovascular conditions (6.0% vs 16.3%, p=0.0002).

Univariate analyses revealed no statistical differences in mortality between encounters with (2.0%) and without (1.8%) ASD. After controlling for other factors, ASD was associated with increased mortality risk (OR=2.33, p=0.0025).

Median LOS (3.0 vs 2.5 days) and median costs ($8,081 vs 6,305) were higher in FXS-ASD however, these differences were not statistically . Multivariate analyses showed no significant differences in LOS (IRR=1.09, CI=0.96-1.23) or costs (IRR=1.15, CI=0.99-1.34).

Conclusion

Among FSX admissions, ASD was associated with higher mortality risk but no differences in LOS or costs compared to admissions without ASD.