[Adherence to long-term therapies and its relevance to epidemiology.]

In Italy, 40% of the population is affected by chronic pathologies, like diabetes, chronic obstructive pulmonary disease (COPD) or heart failure. Chronic diseases are the leading cause of mortality in the world. Although long-term medications are effective, approximately 50% of patients do not take their medications as prescribed. The lack of medication adherence is associated with an increased risk of hospitalization and death. According to recent research, the low adherence to treatment is a multidimensional problem determined by the interaction of patient-related factors, physician-related factors and health system-related factors. In a study of about 10,000 patients, after a hospital discharge for myocardial infarction, only 63% of patients were adherent to poly-therapy in the following two years. The probability of adherence was influenced by disease severity, therapy-related factors, patient's age and comorbidities, post-hospital follow-up visits, and network organizational forms in primary care. Moreover, a relevant variation in adherence to treatment was observed among health care providers. This heterogeneity raises equity concerns in access to optimal care.