Effect of change in patient monthly prescription cost on use of health care services by the South Carolina Medicaid mental health population.

The purpose of this study was to evaluate the effect of the July 2001 prescription limit policy change in the South Carolina Medicaid program on the utilization of health care services and their related costs for adult Medicaid recipients diagnosed with schizophrenia or bipolar disorder. A retrospective cohort study design, identifying subjects with schizophrenia and bipolar disorder, compared their utilization of health care services and associated costs 18 months before and after the policy change (July 2001). Eligible patients were age 21 or older, had a qualifying diagnosis on a hospital or ambulatory claim, and a prescription medication for their diagnosis within 90 days (+/-) of their 1998 or 1999 enrollment date. Total health care expenditure and service utilization were estimated by ordinary least squares regression models and the results contrasted with panel regression methods, specifically random effects models (REM). Additionally, Poisson distribution models were performed on the count data and compared with the results of the panel regression methods. Predictor variables were demographics, inpatient hospitalization, and comorbidities. The results of OLS and panel estimation showed an increase in total cost and the number of ambulatory, hospital, prescription, and nursing home claims after the policy change. Panel estimation showed a positive monthly trend in the post period for all claims. Poisson distribution models were performed on the count data and confirmed the findings of the previous methods. In conclusion, the policy change resulting in an increase in average monthly patient prescription cost was associated with increases in expenditure across all individual categories with the exceptions of Medicare cross-over claims, as well as total expenditure and overall health care utilizations. (PsycInfo Database Record (c) 2021 APA, all rights reserved)