Cost allocation in antihypertensive drug therapies.

The objective of this paper is to evaluate persistence with treatment and resources allocation in antihypertensive pharmacotherapy in a 'real world' population. An administrative database listing all purchased drugs was used to perform a longitudinal analysis. The study included all new users over 20 years of age receiving a first prescription for amlodipine, atenolol, fosinopril, indapamide, or losartan, in an enrolment period of 12 months. The follow-up period lasted 12 months. According to prescriptions dynamics, subjects were classified as same therapy, combination, switching, interruption and occasional utilization. The 34.9% study cohort, persisted with treatment (21.1% on same therapy, 4.7% on combination and 9.1% on switching), while 65.1% did not persist (10.9% on interruption and 54.2% on occasional use). The overall drug cost accounted for persistent (69.0%) and nonpersistent subjects (31.0%). The annual average cost ranged from euro32.80 for occasional users to euro274.69 for those in combination. In clinical practice, a high percentage of patients do not receive adequate antihypertensive therapy, since the 65.1% of subjects did not persist with treatment. This results in a level of pharmaceutical expenditure that cannot be considered appropriately allocated.