Pharmaceutical step-therapy interventions: a critical review of the literature.

BACKGROUND: Adoption of step therapy (ST) is quickly outpacing the market's understanding of its clinical, humanistic, and economic outcomes. The broad scope of previous reviews of drug management programs has prohibited an in-depth discussion of the ST literature specifically.
OBJECTIVE: To conduct a critical review of ST program evaluations, discuss their policy implications, and provide recommendations for future research.
METHODS: PubMed was searched for relevant English-language articles, and references of relevant articles were examined. The ST policy under evaluation had to require use of a first-line agent prior to coverage of a second-line agent.
RESULTS: Fourteen evaluations of ST programs have been published, 7 in commercial populations and 7 in Medicaid. Twelve of the studies empirically examined claims data; 1 was a model; and 1 was limited to patient surveys. Five therapy classes, including antidepressants, antihypertensives, antipsychotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and proton pump inhibitors (PPIs), have been evaluated. The research has consistently found statistically significant drug cost savings with the exception of antipsychotics, where rebates have frequently been excluded. Savings result from greater use of first-line medications and from reduced medication initiation, with the magnitude of noninitiation varying across therapy classes. Three studies have examined medication adherence, producing mixed results. Five studies have empirically examined the effect of ST on hospitalization and emergency room utilization and costs, with none finding statistically significantly higher disease-related utilization or spend, outside of higher outpatient expenditures but not higher outpatient utilization in 1 study.
CONCLUSIONS: The research demonstrates that ST programs for therapy classes other than antipsychotics can provide significant drug savings through the greater use of lower-cost alternatives and, to a lesser extent, reduced drug utilization. The drug savings and clinical impact of ST for antipsychotics are unclear given the research conducted to date, but ST programs for NSAIDs and PPIs can provide significant drug savings without increasing use of other medical services. The research on ST shows gaps in the breadth of evaluation and methodological quality as well as possible study bias. Further research on ST is needed for other therapy classes and for the Medicare Part D population. Recommendations for other areas of research, needed methodological improvements, and reducing the potential for study bias are provided.