Date of Award


Degree Type


Degree Name

Master of Science in Pharmaceutical Sciences


Health Outcomes


Pharmacy Practice

First Advisor

Stephen Kogut


Medication errors are common within the United States health system. Preventable medication errors are often the result of ineffective processes that contribute to the occurrence of adverse drug events. Care transitions, movement between settings or levels of care, present a particularly vulnerable time for patients. Errors are frequently introduced into a patient's medication regimen during transitions of care, including the inappropriate discontinuation or duplication of medications. Inappropriate discontinuation (non-persistence) of evidence based therapies for chronic diseases places patients at an increased risk for adverse health outcomes. Previous investigations have indicated that care transitions due to hospitalization have been associated with increased rates of non-persistence, and that nonpersistent patients were at an increased risk for poor health outcomes.

We conducted a matched retrospective cohort study of patients enrolled with the commercial health insurer Blue Cross Blue Shield of Rhode Island. Patients included in the study were adults at least 18 years of age with diagnosed diabetes confirmed by outpatient medication use and a diagnosis code. We evaluated the disruptive impact of hospitalization on the medication regimen by comparing the odds of persistence with evidence based therapies between hospitalized and non-hospitalized patients. Persistence was assessed with two medication classes: angiotensin converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARBs) and lipid lowering drugs (LLD). We classified patients with an eligible hospitalization as exposed, and matched unexposed non-hospitalized patients to the exposed cohort on the variables age, gender, Charlson comorbidity score and enrollment period. The primary outcomes of persistence and treatment duplication were assessed during the 60 day period following the hospitalized patient's discharge date. Differences in baseline characteristics and the bivariate odds of persistence were assessed between groups for the primary risk factor hospitalization as well as patient demographic and health related variables. We constructed multivariable logistic regression models to measure the effect of hospitalization on persistence with medications from each class while controlling for potential confounders and assessing for interaction terms.

A total of 201 exposed and 199 unexposed ACE inhibitor/ARB users and 202 exposed and 199 unexposed LLD users were evaluated for persistence. After adjusting for potential confounders and an interaction term between hospitalization and cardiovascular disease, hospitalization was found to be a significant risk factor for non-persistence in patients using ACE inhibitors/ARBs [(Beta coefficient- 0.931 [P = 0.0283]). Patients that were hospitalized and had cardiovascular disease had an increased odds of persistence relative to patients that were not hospitalized and had cardiovascular disease (Odds Ratio (OR): 2.052 [95% CI 0.384-10.972)]. Patients that were hospitalized and did not have cardiovascular disease were significantly less likely to persist compared with patients that were not hospitalized and did not have cardiovascular disease (OR: 0.394 [95% CI 0.171-0.906]). The odds of persistence with LLD therapy did not differ between hospitalized patients and non-hospitalized patients (OR: 0.961 [95% CI 0.469-1.972]). The duration of prescription supply for study medication was found to be a confounder of the exposure and outcome relationship for both medication classes. Therapeutic duplication occurred infrequently with both medication classes regardless of exposure status and the low frequencies of duplication observed precluded logistic regression analysis.

Our results implicate hospitalization as a risk factor for non-persistence with medications treating chronic diseases in commercially insured patients with diabetes. Interventions such as medication reconciliation that strive to improve communication during transitions of care and prevent the introduction of errors into the medication regimen should continue to be implemented and evaluated.



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