Previous reviews have shown that changes in prescription drug insurance benefits can impact medication use and adherence. We conducted a systematic review of the literature to identify studies addressing the association between prescription drug coverage and health outcomes. Studies were included if: (1) they involved collecting empirical data surrounding an expansion or restriction of prescription drug coverage and (2) reported on clinical outcomes. Twenty-three studies demonstrated that broader prescription drug insurance reduces use of other health care services, and positively affects outcomes. Coverage gaps or caps on drug insurance generally led to worse outcomes. States should consider implementing the expansions in drug coverage offered by the Affordable Care Act to improve the health of low-income patients receiving state-based health insurance.

ObjectiveThe use of retail purchasing data may improve adherence prediction over approaches using healthcare insurance claims alone.DesignRetrospective.Setting and participantsA cohort of patients who received prescription medication benefits through CVS Caremark, used a CVS Pharmacy ExtraCare Health Care (ECHC) loyalty card, and initiated a statin medication in 2011.OutcomeWe evaluated associations between retail purchasing patterns and optimal adherence to statins in the 12 subsequent months.ResultsAmong 11 010 statin initiators, 43% were optimally adherent at 12 months of follow-up. Greater numbers of store visits per month and dollar amount per visit were positively associated with optimal adherence, as was making a purchase on the same day as filling a prescription (p<0.0001 for all). Models to predict adherence using retail purchase variables had low discriminative ability (C-statistic: 0.563), while models with both clinical and retail purchase variables achieved a C-statistic of 0.617.ConclusionsWhile the use of retail purchases may improve the discriminative ability of claims-based approaches, these data alone appear inadequate for adherence prediction, even with the addition of more complex analytical approaches. Nevertheless, associations between retail purchasing behaviours and adherence could inform the development of quality improvement interventions.

This work was supported by an unrestricted grant from CVS Health to Brigham and Women's Hospital. Shrank, Brennan, and Matlin were employees and shareholders at CVS Health at the time of this manuscript preparation; they report no financial interests in products or services that are related to the subject of the manuscript. Franklin has received consulting fees from Aetion. Chourdry has received grants from the National Heart, Lung, and Blood Institute, PhRMA Foundation, Merck, Sanofi, AstraZeneca, and MediSafe. Spettell is an employee of, and shareholder in, Aetna. The other authors have nothing to disclose. Krumme, Choudhry, Tong, and Franklin contributed to the study design, interpretation of results, and manuscript drafting. Tong prepared and analyzed the data. Isaman, Spettell, Shrank, Brennan, and Matlin provided interpretation of results and critical manuscript revisions.