The Effect of Health Insurance Characteristics on Outpatient Mental Health Care and Substance Abuse Treatment Utilization among Privately-Insured Employees and their Dependents
- Presenter:
Chair: Michael Grossman; Discussant: Adetokunbo Oluwole Mon June 5, 2006 10:45-12:15 Room 309
Rationale: Although many studies exist that have examined the effect of private health insurance on demand for medical care, few studies have examined this relationship for mental health care or substance abuse treatment demand. Those studies that have examined MH/SA treatment demand have often focused on health insurance per se rather than examining specific effects of MH/SA plan coverage. Furthermore, many of these studies use data limited to service-using individuals and are unable to examine the effect of health insurance on any use of MH/SA care as well as level of use among service users.
Objective: The objective of this study is to estimate the effect of specific MH/SA health insurance characteristics on outpatient utilization of mental health and substance use treatment services for privately-insured employees and their dependents.
Methodology: We use a two-part model to estimate the effect of MH/SA health insurance characteristics on the likelihood of any use of outpatient MH or SA services and, conditional on use, the number of outpatient days. Our models include 4 variables representing MH/SA health insurance coverage, including three different measures of coinsurance rates and whether the health plan required precertification by the company’s employee assistance program (EAP) prior to MH/SA service use. Any use is modeled using a random-effects logit model and days of use is modeled using a random-effects negative binomial model. Both models are estimated using an instrumental variable approach to deal with potential endogeneity of the health insurance characteristics. Data used are private insurance enrollment and claims data for 1997-1998 from MEDSTAT’s Marketscan® database.
Results: We find that the outpatient coinsurance rate for in-network MH/SA is positively and significantly associated with any outpatient MH use, although the estimated marginal effect is quite small. Contrary to our expectations, employees’ number of outpatient MH care days received decreases as the in-network coinsurance rate increases. But again, this effect is extremely small. Among health insurance characteristics, the strongest predictor of MH use is the EAP precertification requirement which is negatively associated with MH use. Our analysis of substance use treatment finds little significant association between MH/SA health insurance variables and outpatient SA treatment utilization.
Conclusions: Our findings suggest that employees and their dependents do respond to expected out-of-pocket expenses for outpatient MH care, but this response is very small. Furthermore, MH/SA health characteristics appear to have little or no effect on SA treatment utilization. Finally, our results indicate that the role of an EAP is not straightforward. Rather than facilitating treatment access, EAP precertification may create an obstacle to treatment and discourage utilization. However, it is also possible that EAP precertification may decrease utilization through the formal health care system by providing some MH/SA services. Individuals with milder conditions may receive an adequate dose of services through the EAP and, therefore, not need additional services.
