Retrospective assessment of Medicaid step-therapy prior authorization policy for atypical antipsychotic medications.
BACKGROUND
Antipsychotic medications account for more prescription expenditures in Medicaid than any other therapeutic category. This has made them an attractive target for states hoping to curtail rising expenditures.


OBJECTIVE
The objective of this study was to document the effects of a step-therapy prior authorization (PA) policy for atypical antipsychotic medications on: (1) Medicaid prescription expenditures among all Medicaid beneficiaries and (2) prescription and health service expenditures among patients with schizophrenia.


METHODS
Prescription, inpatient, outpatient, and long-term care State Medicaid Research Files from Georgia and Mississippi from January 1, 1996, to December 31, 1997, were used to model an interrupted time-series analysis. We compared a step-therapy PA policy implemented in Georgia to a nonequivalent/no-treatment control group (Mississippi) over 10-month prepolicy, 11-month policy, and 3-month postpolicy periods. Segmented regression was used to estimate antipsychotic prescription expenditures among all eligible Medicaid beneficiaries. We used generalized estimating equations to model prescription and other health service expenditures with difference-indifference regressions among a cohort of patients with schizophrenia.


RESULTS
Compared with Mississippi, Georgia saved approximately USD 7 million in atypical antipsychotic expenditures over the 11-month policy period. Among patients with schizophrenia, the PA policy was associated with a USD 19.62 per member per month (PMPM) decrease in atypical antipsychotic expenditures and a USD 2.20 PMPM increase in typical antipsychotic expenditures (both, P < 0.001). Among the same patients with schizophrenia however, the reduction in atypical antipsychotic expenditures was accompanied by a USD 31.59 PMPM increase in expenditures for outpatient services (P < 0.001).


CONCLUSIONS
Although PA of atypical antipsychotics was associated with significant prescription savings to the Georgia Medicaid program, among a vulnerable cohort of patients with schizophrenia, an increase in outpatient expenditures was associated with overall savings.
Farley
Joel F
JF
Division of Pharmaceutical Outcomes and Policy, School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, USA. jffarley@unc.edu
Cline
Richard R
RR
Schommer
Jon C
JC
Hadsall
Ronald S
RS
Nyman
John A
JA
D000367:Age Factors; D014150:Antipsychotic Agents / Q000191:economics* / Q000627:therapeutic use; D005260:Female; D006296:Health Services / Q000191:economics* / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008484:Medicaid / Q000191:economics / Q000458:organization & administration*; D008605:Mental Health Services / Q000191:economics / Q000706:statistics & numerical data; D008875:Middle Aged; D010593:Pharmaceutical Services / Q000191:economics / Q000706:statistics & numerical data; D012051:Reimbursement Mechanisms; D012189:Retrospective Studies; D012559:Schizophrenia / Q000191:economics* / Q000628:therapy; D012737:Sex Factors; D014481:United States
D014150:Antipsychotic Agents