RESUMEN
BACKGROUND: Our purpose was to establish, by means of a survival analysis, the duration of therapeutic compliance and the probability of abandonment or prescription drugs in cardiovascular patients, as well as the prognostic factors that determine it. PATIENTS AND METHOD: Longitudinal observational study (1996-1998). By means of a consecutive sampling, 493 patients who initiated a cardiovascular treatment were selected. Through interviews, we obtained information on cardiovascular problems and treatment, concomitant diseases, consumption of other drugs and social and demographic variables. The consumption of prescribed drugs was established across 6 periodic observations. RESULTS: During the observational period, 39.4% of drugs prescribed by the general practitioner (GP) were abandoned, as compared to 22.4% of those prescribed by specialists (p < 0.05). The degree of abandonment was significantly higher among consumers of vasodilators and vasoprotective agents. Cardiac glycosydes and angiotensin converting enzyme inhibitors were among the therapeutic subgroups in which a longer survival time was observed (average: 19.8 and 16.5 months, respectively). By a Cox regression analysis, we noticed that the risk of abandonment was higher in patients who took two or more doses of the drug per day (OR = 2.8; 95% IC, 21-37), in consumers of medicines with a daily cost lower than ptas. 100 (OR = 1.4); 95% CI, 1.0-1.8) and in subjects younger than 65 years (OR = 1.3; 95% CI, 1.0-1.8). CONCLUSIONS: A higher degree of abandonment of cardiovascular medication occurs when it is administered in primary health-care (i.e., drugs prescribed by the GP), mainly in relation to a greater prescription of agents with a low therapeutic effectiveness. Abandonment is influenced by patients' social and demographic factors and also by the specific characteristics of the treatment.