Do prior authorization policies discourage first-line antipsychotic use in patients newly discharged from a hospitalization for schizophrenia in Saskatchewan?

BACKGROUND

Drug benefit providers can decrease prescribing of specific medications through prior authorization policies. In Saskatchewan, certain second generation antipsychotics (SGAs) are recognized as first-line agents to manage schizophrenia; but, require prior authorization because their coverage is restricted in other conditions. We aimed to determine if the need for prior-authorization substantially diminishes prescribing of first-line SGAs in comparison to unrestricted agents.

OBJECTIVES

To conduct an ecological comparison of SGA prescribing with changes in prior- authorization policies between 1997 and 2005 using health-administrative databases in Saskatchewan, Canada.

METHOD: Eligible subjects were discharged from hospital with a first-time primary diagnosis of schizophrenia between 1997 and 2005. SGAs dispensed within 7 days of discharge were used to estimate prescribing preferences for olanzapine and quetiapine relative to risperidone. Percentages of SGA use were age and sex standardized to the 2000 cohort.

RESULTS

Out of 1,277 eligible patients, 521 (41%) received 564 SGA dispensations within 7-days of hospital discharge. Between 1997 and 1998, risperidone was the only SGA covered for first-line use and made up 72.6% (82/113) of SGA use while olanzapine made up 27.4% (31/113) for a crude preference ratio of 0.38 (27.4/72.6). Risperidone use decreased to 65.8% in 1999-2002 and to 47.4% in 2003-2005 as a percentage of SGA dispensations. Correspondingly, the preference ratios for olanzapine and quetiapine increased from 0.40 to 0.57 and from 0.12 to 0.54 in these respective periods.

CONCLUSIONS

The requirement for prior-authorization does not appear to substantially diminish prescribing of first-line SGAs for the treatment of schizophrenia in Saskatchewan, Canada.