Lead/Presenter: Amy Linsky,
COIN - Bedford/Boston
All Authors: Linsky AM (Center for Healthcare Organization and Implementation Research, Boston), Stolzmann K (Center for Healthcare Organization and Implementation Research, Boston), Simon SR (Center for Healthcare Organization and Implementation Research, Boston) Cabral H (Department of Biostatistics, Boston University School of Public Health) Rosen AK (Center for Healthcare Organization and Implementation Research, Boston)
Unintentional therapeutic duplications may lead to the availability of medication excess, placing patients at risk of inadvertently taking doses higher than are safe, with possibility of patient harm. We determined the prevalence of potential medication excess in the Veterans Health Administration (VA) and identify associated patient and system factors.
We conducted a retrospective database study of all Veterans who received > = 1 prescription dispensed by a VA pharmacy. The primary outcome of "medication excess" was defined for each patient as the number of excess days' worth of pills for all overlap episodes (concurrently dispensed medications with the same name for > 10 days). Predictors included age; gender; marital status; Elixhauser comorbidity score; number of sites of care, prescribers, primary care visits, medical subspecialty visits, surgery visits, and psychiatry visits; proportion of medications filled by the consolidated mail order pharmacy (CMOP, all vs. some vs. none); proportion of medications filled as > = 90-day supply (all vs. some vs. none); and copay requirement. Multivariable negative binomial regression analyses estimated the rate ratio of each predictor with medication excess.
Among 4,687,453 Veterans, 64% had > = 1 medication overlap episodes. Patients were prescribed a median of 7 (IQR 3-12) unique medications, had a median of 2 (IQR 0-5) overlap episodes, and a median of 27 (IQR 0-96) days of medication excess. In adjusted regression models, factors associated with greater risk of medication excess included proportion with > = 90 day-supply (all: 2.99 [95%CI 2.97-3.01]; some: 4.94 [95%CI 4.91-4.97]; none [ref]); proportion filled by CMOP (all: 3.10 [95%CI 3.08-3.13]; some: 4.13 [95%CI 4.10-4.17]; none [ref]); multiple prescribers ( > 4: 2.58 [95%CI 2.56-2.60]; 2-4: 1.62 (95%CI 1.61-1.63); 1 [ref]); mental health visits ( > 9: 1.57 [95%CI 1.56-1.59]; 1-9: 1.22 [95%CI 1.21-1.23]; 0 [ref]); and Elixhauser score ( > 3: 3.13 [95%CI 3.11-3.15]; 1-3: 2.07 [95%CI 2.06-2.08]; 0 [ref]).
Medication excess was high among this population of VA users, with nearly two-thirds of patients experiencing at least one duplication.
As systems such as mail-order pharmacies and 90-day supply are increasingly implemented to reduce costs and improve medication adherence, it is important to recognize the potential for increased duplicative medications and subsequent harm.