Impact of pharmacy services on initial clinical outcomes and medication adherence among veterans with uncontrolled diabetes

BACKGROUND: Diabetes remains a growing public health threat but evidence supports the role that pharmacists can play in improving diabetes medication use and outcomes. To improve the quality of care, the Veterans Health Administration has widely adopted care models that integrate clinical pharmacists, but more data are needed to interpret the impact of these services. Our objective was to assess clinical pharmacy services’ impact on outcomes and oral antidiabetic medication (OAD) use among veterans with uncontrolled diabetes in the first year of therapy. METHODS: This was a retrospective cohort analysis using the Veterans Affairs (VA) Corporate Data Warehouse to identify the first diagnosis of and initiation of OAD therapy for uncomplicated, uncontrolled diabetes (A1C > 7.0%) during 2002–2014. Receipt of clinical pharmacy services was identified using codes within VA electronic health records, and clinical values were obtained at or near the initial fill date and 365 days later. Use of OADs was assessed by proportion of days covered (PDC) for one year following the first filled prescription. Veterans having received clinical pharmacy services were matched 1:1 to those having not seen a clinical pharmacist in the first year of therapy, and generalized linear models assessed changes and differences in outcomes. RESULTS: The analysis included 5749 patients in each cohort. On average, patients saw a clinical pharmacist 2.5 times throughout the first year of OAD therapy. Adherence to OAD medications was higher in veterans having seen a pharmacist (84.3% vs. 82.4%, p < 0.0001) and more such patients achieved a PDC of at least 80% (72.2% vs. 68.2%, p < 0.0001). After one year of OAD therapy, mean change in hemoglobin A1C was greater among those receiving pharmacy services (− 1.5% vs. -1.4%, p < 0.0001). CONCLUSION: Pharmacist participation in diabetes patients’ primary care positively affects the multifaceted needs of patients with this condition and comorbid chronic disease. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12913-018-3665-x) contains supplementary material, which is available to authorized users.