An Interrupted Time Series Analysis of the Mental Health Parity and Addiction Equity Act's Impact on Utilization and Expenditures Among Behavioral Health Care 'Carve-In' Enrollees

• Activity Number: 377
• Type: Contributed
• Date/Time: Tuesday, August 11, 2015 : 10:30 AM to 11:15 AM
• Sponsor: Health Policy Statistics Section
• Author(s): Jessica Harwood* and Susan L. Ettner
• Companies: and UCLA
• Keywords: segmented regression ; interrupted time series ; longitudinal data ; claims data ; mental health / substance abuse ; parity

Abstract

The federal Mental Health Parity and Addiction Equity Act of 2008 (MHPAEA) requires that for plans renewing on or after 1/1/2010, employer groups offering mental health and/or substance abuse (MH/SA) coverage cannot apply financial requirements (deductibles/copayments) or treatment limits (number of visits/days of coverage) that are more restrictive than requirements or limits applying to medical/surgical benefits. The Interim Final Rule (IFR) took effect on 1/1/2011 and added that parity also applies to non-quantitative treatment limits (pre-authorization/medical necessity review/reimbursement rates/drug formulary design). We use eligibility and behavioral health claims data from the largest managed behavioral health organization in the U.S. to examine the association of MHPAEA and the IFR with MH/SA utilization and expenditures by payer. Analyses presented focus on patients who were enrolled in "carve-ins." One challenge we faced was the lack of a reasonable comparison group for this population. We chose an interrupted time series design to evaluate the longitudinal effect of MHPAEA and the IFR. Segmented regression analysis was used to estimate the effects of MHPAEA and the IFR.