Effect of Outpatient Service Utilization on Hospitalizations and Emergency Visits Among Youths With Autism Spectrum Disorder

The final sample included 104,381 children and young adults with ASD across all 50 states. Approximately 9% of the study sample had at least one psychiatric hospitalization between 2008 and 2012; there was a higher incidence of ED visits, with 14% of the study sample experiencing at least one ED visit with an associated psychiatric code (Table 1). The mean±SD age at baseline was 8.5±4.6, and the sample was more than 80% male. The most common insurance type was point of service (64.9%), followed by preferred provider organizations (13.9%), health maintenance organizations (13.6%), and exclusive provider organizations (7.3%); only 12% of the children were enrolled in a high-deductible health plan. On average, weekly spending on ASD-specific outpatient services was $36 compared with $53 for non-ASD outpatient services.

First, we plotted the trajectory of average weekly spending on ASD-specific outpatient services leading up to a psychiatric hospitalization or ED visit among all children and young adults who experienced either event to determine the appropriate construction of spending measures. Spending was relatively constant until 5 to 6 weeks before an event, when it increased moderately and then spiked during the 2 weeks prior to the event (Figure 1).

Next, we performed complementary log-log regression analyses and found a positive association between the likelihood of psychiatric hospitalizations and greater spending on ASD-specific outpatient services in the 2 weeks prior (HR=1.12; p<0.001) to the hospitalization, as well as in the 3 to 6 weeks prior (HR=1.06; p<0.001) to the hospitalization (Table 2). Conversely, greater spending on ASD-specific outpatient services in the 7 to 14 weeks prior to the psychiatric hospitalization was associated with a lower incidence of psychiatric hospitalization (HR=0.98; p=0.011).

As with psychiatric hospitalizations, greater spending on ASD-specific outpatient services in the 2 weeks prior (HR=1.08; p<0.001) and 3–6 weeks prior (HR=1.03; p=0.033) to a psychiatric ED visit was positively associated with the likelihood of the event, but there was no association between the likelihood of a psychiatric ED visit and spending on ASD-specific outpatient services in the 7 to 14 weeks prior (HR=1.00; p=0.631) to the ED visit.

Greater non–ASD-specific spending in all time periods was positively associated with both psychiatric hospitalizations and ED visits. With the exception of stimulants, having a prescription for a psychotropic medication was positively associated with incidence of both kinds of events.

In our analyses of the monthly spending measures for each patient, findings were qualitatively similar (see Appendix A in the online supplement). Results were robust as analyzed with other statistical approaches as well, including Cox regression analyses (see Appendix B in the online supplement). We also performed subanalyses based on quintiles of average spending in the 7- to 14-week period, which is the measure most likely to capture treatment as usual (see Appendix C in the online supplement). In the highest-spending quintile, the 7- to 14-week measure had a larger impact on the likelihood of psychiatric hospitalizations compared with the full sample (HR=0.95; p<0.001). In the lowest-spending quintile, spending in the 7–14 weeks prior to an event had an even larger effect (HR=0.08; p=0.008). Notably, there was a negative and significant effect of spending during the 7 to 14 weeks prior to an event on ED visits in the highest-spending quintile (HR=0.95; p<0.001). Finally, we examined the consistency of the home and community-based care children received (see Appendix D in the online supplement). While it is difficult to measure consistency in claims, we created a binary variable that indicated whether the patient received ASD-specific outpatient services in each of the 7 to 14 weeks prior to the psychiatric hospitalization or ED visit. The consistency variable was negatively associated with psychiatric hospitalizations (HR=0.70, p=0.007) but not with ED visits (HR=1.01, p=0.830).

The utilization of home and community-based care may lower the risk of psychiatric hospitalizations and ED visits for children and young adults with ASD, but there has been little evidence to support this hypothesis. In part, this is because most studies focus on more proximate service utilization (e.g., 30 days surrounding an event) and therefore do not allow for differential effects of less recent utilization. Our study addressed this gap by constructing spending measures for periods closer to and further from a given psychiatric hospitalization or ED visit.

Results showed that less recent spending on ASD-specific outpatient services—specifically, spending during the 7 to 14 weeks prior to an event in a given week—reduced the likelihood of a psychiatric hospitalization in that week. Spending on service utilization in the weeks closer to the psychiatric hospitalization did not decrease the risk, which suggests that these services were associated with increased symptomatology and therefore were delivered too late to prevent the hospitalization. On average, there was no evidence that spending on ASD-specific outpatient services reduced the likelihood of a psychiatric ED visit.

These results highlight a potential benefit of home and community-based care, especially when those services are not contingent on the manifestation of aggressive or self-injurious behaviors that may lead to psychiatric hospitalizations. The observed effect was small—each additional $1,000 in spending during the 8-week period ($125 per week during the 7–14 weeks before an event) was associated with a 2% reduction in the risk of a psychiatric hospitalization. For comparison, that is more than twice the average conditional spending on ASD-specific outpatient services over an 8-week period ($881, SD: $2,179). However, it is far less than the average conditional spending on psychiatric hospitalizations in a single week ($4,323, SD: $4,066).

While the effect is modest, the main finding may be attenuated because there was no available measure of patients’ clinical or functional severity in the data. Estimating any inverse association between spending on outpatient services and psychiatric hospitalizations without this information illustrates the robustness of this result. One might expect these findings to differ based on severity of illness or prior utilization of services, a result which our sensitivity analyses suggest. One might also expect these findings to differ based on the consistency of services received; in other sensitivity analyses, we found a larger protective effect when services were delivered every week. These additional results suggest that there are different mechanisms through which ASD-specific outpatient services can decrease the risk of psychiatric hospitalizations for children and young adults with ASD.

Our findings diverge from previous work by Mandell and colleagues (17), who found that respite care, but not outpatient care, reduced the likelihood of psychiatric hospitalizations for children with ASD. No information on respite care was available for the present study, and this kind of care is rarely covered by commercial insurance (20). The difference in results could stem, at least in part, from higher reimbursement rates and a wider network of providers in commercial insurance than in Medicaid, which may translate into commercially insured patients accessing care more easily than patients with Medicaid (21, 22). The results also could be driven by differences in quality, but little research has directly compared the quality of services delivered to individuals with ASD across different types of insurance.

Even if these services reduce the likelihood of adverse events, it may be difficult for some individuals with ASD to access home and community-based care—more than half of caregivers have reported difficulty accessing services, with one in five lacking a usual source of care (23). One reason for this difficulty is a shortage of trained providers (24), some of whom have raised concerns about the lack of training opportunities in evidence-based practices to treat patients who have ASD (25). Addressing these barriers could improve the overall value of health care by reducing the use of costlier and more restrictive services, such as psychiatric hospitalizations. Other hurdles that families face, such as uncertainty about which treatments are covered by insurance, may mean that only those families that can effectively navigate health care delivery are able to utilize consistent, high-quality home and community-based care for ASD (26).

Several limitations of this study should be noted. First, ASD diagnoses were not verified through clinical review, although the approach we used (i.e., determining a diagnosis on the basis of two ASD claims on separate days) has been shown to have high positive predictive value (27). Second, we do not have any information on school-based or other services not paid for by insurance and thus may have underestimated the amount of care a child received, which would have biased our findings if children and young adults with ASD experiencing psychiatric hospitalizations or ED visits used these services at a different rate than those not experiencing such events. Third, we did not control for the quality of care, which can have an impact on the effectiveness of the services utilized. Fourth, spending measures were selected based on the trajectories of ASD-specific outpatient spending as demonstrated in Figure 1, but they may not be the most appropriate measures of service utilization. Fifth, our measures of psychotropic prescription drugs filled only covered the week prior to a psychiatric hospitalization or ED visit and cannot be used to distinguish acute versus chronic medication use.

Finally, our results have not demonstrated that a $1,000 increase in spending on ASD-specific outpatient services during the course of 8 weeks is necessary for every child with ASD—instead, they suggest that more utilization of home and community-based care can confer protective benefits to children and young adults with ASD who are at risk of hospitalization. Of note, other benefits associated with reduced risk of psychiatric hospitalization via increased outpatient service utilization were not included in our analyses.

Despite these limitations, our findings have important implications. The financial burden associated with ASD is extensive, and psychiatric hospitalizations remain the most expensive type of service for youths with ASD (28, 29). Policies such as ASD insurance mandates and mental health parity laws may increase spending on outpatient services by insurers initially (30, 31), but our results suggest that some of the financial burden could be reduced in the long term, because children with ASD who received more home and community-based care had a lower risk of experiencing psychiatric hospitalizations. A better understanding of the mechanisms by which psychiatric hospitalizations occur in children and young adults with ASD may further reduce the likelihood of these adverse events.