(854) Comparing in-hospital outcomes in patients with co-occurring autism and epilepsy to patients with epilepsy alone and autism alone: a population-based study

Rationale: Autism and epilepsy commonly co-occur. Understanding trends in healthcare utilization and in-hospital outcomes amongst patients with autism and epilepsy can help optimize care and reduce costs. We compared hospital outcomes amongst patients with autism and epilepsy to those with epilepsy alone and to those with autism alone. Differences in discharge status, in-hospital mortality, mean length of stay (LOS) and cost were examined as well as common reasons for admission and procedures performed.

Methods: Admissions amongst patients with epilepsy alone, autism alone, and co-occurring autism and epilepsy were identified in the 2003-14 National Inpatient Sample (NIS) using previously validated ICD-9-CM case definitions. The NIS is the largest U.S. all-payer nationally representative database and includes patients and hospital-level variables. Two cohorts were matched by age and sex: 1) one patient with co-occurring epilepsy and autism to three epilepsy patients, 2) one patient with co-occurring epilepsy and autism to three autism patients. Multinomial logistic regressions were performed to compare the outcomes of interest in persons with comorbid autism and epilepsy to persons with epilepsy alone in one analysis, and to persons with autism alone in a second analysis.

Results: Data were collected on 9,241 (mean age: 23.33±0.34; 27.00% female) hospital admissions in persons with comorbid autism and epilepsy, 27,723 (mean age: 23.36±0.31; 26.94% female) matched controls with epilepsy alone and 27,723 (mean age: 23.26±0.25; 27.13% female) matched controls with autism alone. As compared to patients with epilepsy alone, patients with autism and epilepsy had lower odds of discharge against medical advice (OR=0.44, 95%CI=0.31-0.62, p< 0.0001), higher odds of in-hospital mortality (OR=1.34, 95%CI=1.06-1.68, p=0.0127), and a longer mean LOS (5.63 days vs. 5.12 days, p< 0.0001). As compared to patients with autism alone, patients with autism and epilepsy had greater odds of being transferred to another facility (OR=1.15, 95%CI=1.05-1.24, p=0.0013), shorter mean LOS  (5.63 days vs 6.99 days, p< 0.0001) and a higher mean cost of hospitalization ($37,158 vs $32,890, p< 0.0001). Infections (pneumonia, septicemia or aspiration pneumonitis in the primary diagnostic position) were more common in patients with autism and epilepsy compared to those with autism alone (11.59% vs 7.00%, p< 0.0001) and epilepsy alone (11.59% vs 11.21%, p=0.40). Intubation and mechanical ventilation were more common for patients with autism and epilepsy than for those with autism alone (4.60% vs 2.65%, p< 0.0001).

Conclusions: Significantly greater odds of death are seen in those with comorbid autism and epilepsy vs. epilepsy alone and increased infections are seen in those with comorbid autism and epilepsy vs. autism alone. Future research should focus on targeted interventions to improve outcomes in each of these comorbid groups, particularly those that are preventable.

Funding: Please list any funding that was received in support of this abstract.: None