Relationship Between Medication Adherence and Distance to Dispensing Pharmacies and Prescribers Among an Urban Medicaid Population with Diabetes Mellitus

STUDY OBJECTIVE

To determine whether a relationship exists between medication adherence to angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) and distance to dispensing pharmacies and prescribers among an urban public aid population with diabetes mellitus.

DESIGN

Retrospective cohort study using claims data.

DATA SOURCE

Illinois Department of Healthcare and Family Services database.

PATIENTS

A total of 6532 patients aged 18-64 years with diabetes who had at least one prescription fill for an ACEI or ARB and had continuous Medicaid coverage in the greater Chicago area in 2009.

MEASUREMENTS AND MAIN RESULTS

We assessed medication adherence, defined as proportion of days covered (PDC) of 0.8 or higher, to ACEIs and ARBs and its association with distances between patients and their pharmacies and prescribers. Of the 6532 patients included in the analyses, 2930 (45%) had PDC levels of 0.8 or higher. No significant differences were observed between patients who were adherent versus those who were nonadherent in distance to pharmacy (median 1.39 vs 1.35 miles, p=0.15) or distance to prescriber (median 4.39 vs 4.48 miles, p=0.80). In a multivariate regression model including age, sex, race/ethnicity, number of pharmacies, number of prescribers, distance to pharmacy, and distance to prescriber, a greater number of prescribers was associated with higher adherence (two prescribers vs one prescriber: odds ratio [OR] 1.396, 95% confidence interval [CI] 1.233-1.580; three or more prescribers vs one prescriber: OR 2.208, 95% CI 1.787-2.727).

CONCLUSION

ACEI or ARB adherence was not associated with distances to pharmacies and prescribers.

Traveling towards disease: transportation barriers to health care access

Transportation barriers are often cited as barriers to healthcare access. Transportation barriers lead to rescheduled or missed appointments, delayed care, and missed or delayed medication use. These consequences may lead to poorer management of chronic illness and thus poorer health outcomes. However, the significance of these barriers is uncertain based on existing literature due to wide variability in both study populations and transportation barrier measures. The authors sought to synthesize the literature on the prevalence of transportation barriers to health care access. A systematic literature search of peer-reviewed studies on transportation barriers to healthcare access was performed. Inclusion criteria were as follows: (1) study addressed access barriers for ongoing primary care or chronic disease care; (2) study included assessment of transportation barriers; and (3) study was completed in the United States. In total, 61 studies were reviewed. Overall, the evidence supports that transportation barriers are an important barrier to healthcare access, particularly for those with lower incomes or the under/uninsured. Additional research needs to (1) clarify which aspects of transportation limit health care access (2) measure the impact of transportation barriers on clinically meaningful outcomes and (3) measure the impact of transportation barrier interventions and transportation policy changes.