Substance abuse treatment duration for Medicaid versus commercial clients in a health maintenance organization.

Background: As Medicaid clients have come to be enrolled in managed care, concerns have arisen about the ability of private sector systems to meet the needs of enrollees with substance abuse problems.

Objectives: This project describes treatment initiation and duration for Medicaid and commercial substance abuse treatment clients in a large health maintenance organization (HMO).

Research Design: This study was a prospective secondary analysis of information from HMO databases. Subjects were 641 adult Medicaid clients who contacted the HMO's addiction medicine department in 1996 or 1997 and commercial HMO addiction medicine patients (n=447). First contact with addiction medicine during the study period was the index event.

Measures: Chief dependent variables were initiation and duration of substance abuse treatment after the index event.

Results: Logistic regression showed that longer HMO enrollment predicted treatment initiation after substance abuse assessment, but Medicaid status was not a significant predictor. A competing risks analysis using Cox proportional hazards models indicated that once subjects had initiated, Medicaid was not significantly related to exit from substance abuse treatment. Analysis of health plan disenrollment by Medicaid clients indicated that the most common reason was loss of Medicaid eligibility.

Conclusions: These results raise the possibility that state Medicaid policies may make it difficult for clients to obtain suitable chemical dependency treatment services.