Factors involved in the discontinuation of antihypertensive drug therapy: an analysis from real life data.

Abstract

We have previously shown that in Italian region of Lombardy (about 10 million citizens), adherence to antihypertensive treatment is low, and that this is associated with a greater risk of hospitalization for cardiovascular events. In this study, we used a healthcare database to study the factors involved in discontinuation of antihypertensive drug prescriptions in real life. The analysis was restricted to 493 623 new users of antihypertensive drugs (no prescriptions in the previous 3 years) recruited in 2003, 2006 and 2009. Discontinuation was defined as lack of prescription renewal for at least 3 months. Each patient was followed at most for 1 year. The adjusted risk of treatment discontinuation depended on the type of initial antihypertensive treatment (diuretic monotherapy associated with higher risk) and it was lower in men (-17%) and older (-21 to -29%) patients, in patients with co-treatment with antidiabetic drugs, or hospitalization for cardiovascular or renal disease (-12 to -27%), but greater in patients under co-treatment with antidepressant drugs or hospitalization for concomitant pulmonary, rheumatic, neoplastic or neurological diseases (+9 to +32%). An unexpected relationship between discontinuation of treatment and density of the population of patient's residence, with a much greater discontinuation in metropolitan areas, was observed. In a real life setting, discontinuation of antihypertensive treatment is affected in an opposite direction by a large number of factors: type of antihypertensive treatment, co-treatments, clinical conditions and even demographic characteristics of the geographical area where the patient lives. Knowledge of these factors may help the effort to reduce this phenomenon.