Older patients and geographic barriers to pharmacy access: When nonadherence translates to an increased use of other components of health care.

This paper studies whether geographic barriers can influence nonadherence to prescription drugs and its effect on patients' health. We used a multivariate probit model estimated by maximum simulated likelihood that considers individual unobserved heterogeneity, which may characterize the relationship between adherence, medical care utilization, and health outcome. We used administrative data from Liguria, Italy, the region with the highest rate of individuals over the age of 65 in Europe. Our sample included older individuals affected by cardiovascular diseases, which remain one of the leading causes of death in most OECD countries. Our results showed that geographic barriers to pharmacies negatively influence patients' adherence. According to our results, patients' nonadherence to pharmacological therapy is responsible for an increased probability of patients' mortality and the overuse of other medical services, namely, hospitalizations and emergency department visits. Nonadherence may thus represent a potential source of waste for the health care system.