Substance abuse service utilization under managed care: HMOs versus carve-out plans

Managed behavioral health care organizations are increasingly managing Amer icans' substance abuse by using carve-outs, but little information is avail able about how this has affected service utilization and costs when compare d to HMOs. One employer's claims for substance abuse services delivered und er a carve-out arrangement are compared to prior HMO claims information. Un der the carve-out arrangement, inpatient and outpatient service utilization are found to decrease, but intermediate service utilization dramatically i ncreases. Costs per unit service decrease for all services. The pattern of changes is different from that seen for mental health services, suggesting that different factors may be applicable to substance abuse services.