RESUMO
The objective of this study was to investigate stay-on-therapy patterns over 3 years among patients prescribed different classes of antihypertensive drugs for the first time. A retrospective analysis of information recorded in the drugs database of the Local Health Unit of Ravenna (Italy) was carried out on 7312 subjects receiving a first prescription for diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II antagonists between 1 January and 31 December 1997. Patients were followed up for 3 years. All prescriptions of antihypertensive drugs filled during the follow-up periods were considered. The patients continuing or discontinuing the initial treatment, the duration of treatment, and the doses taken were all calculated, as well as main factors influencing the persistence rate. The drugs prescribed were predominantly ACE-inhibitors, followed by calcium channel blockers, diuretics, beta-blockers and angiotensin II antagonists. A total of 57.9% of patients continued their initial treatment during the 3-year follow-up period, 34.5% discontinued the treatment, whilst 7.6% were restarted on a treatment in the third year. Persistence with treatment was influenced by: age of patient (persistence rate increasing proportionately with advancing years), type of drug first prescribed (persistence rate higher with angiotensin II antagonists, progressively lower with ACE-inhibitors, beta-blockers, calcium channel blockers and diuretics), gender of patient (persistence was better in males), age of general practitioner (GP) (the younger the GP, the better the persistence rate) and gender of GP (better stay-on-therapy rate with male GP prescribing). In the case of patients treated continuously, mean daily dose increased progressively over the 3 years. With adequate markers, helpful data can be collected from prescription claims databases for the purpose of monitoring the persistence of patients in continuing their medication, and the quality of antihypertensive treatment in a general practice setting.
