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

OBJECTIVES:: 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. METHODS AND RESULTS:: 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. CONCLUSIONS:: 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.