Changes in ambulatory utilization after switching from Medicaid fee-for-service to managed care.

OBJECTIVES: To observe any change in ambulatory care utilization after switching from Medicaid fee-for-service (FFS) to Medicaid managed care (MC). STUDY DESIGN: We conducted a statewide longitudinal study of 21,048 adult Medicaid beneficiaries in New York State who switched from FFS to MC in 2011 or 2012, with 2 sets of controls (n = 21,048 with continuous FFS; n = 21,048 with continuous MC) who were matched on age, gender, dual-eligible status, and number of chronic conditions. METHODS: We measured ambulatory care utilization in the 12 months before and 12 months after the switch date, using regression to adjust for case mix and account for matching. RESULTS: Overall, switching from Medicaid FFS to Medicaid MC was associated with greater absolute decreases over time in ambulatory visits and providers compared with controls (-1.49 visits vs continuous FFS and -1.60 visits vs continuous MC; each P <.0001; -0.10 providers vs continuous FFS and -0.12 providers vs continuous MC; each P <.0001). The subset of switchers with 5 or more chronic conditions had the greatest absolute decreases in visits (-5.88 visits vs continuous FFS and -5.98 visits vs continuous MC; each P <.0001) and providers (-1.37 providers vs continuous FFS and -1.39 providers vs continuous MC; each P <.0001). Significant decreases in visits and providers were also observed for switchers with 3 to 4 chronic conditions but not for those with 0 to 2 chronic conditions. CONCLUSIONS: Switching from Medicaid FFS to Medicaid MC was associated with a decrease in ambulatory utilization, especially for the sickest patients.