Initial treatment of hypertension and adherence to therapy in general practice in Italy

Antihypertensive agents are among the most used therapeutic classes. The approach to the pharmacological treatment of hypertension is guided by international recommendations and adherence to treatment is known to result in effective prevention of cardiovascular risk. The aim of this study was to evaluate the pattern of use of antihypertensive agents in general practice in terms of drug choice for the initial treatment of hypertension and adherence to treatments among newly recruited patients. We collected the data of all antihypertensive drugs prescribed by general practitioners (GPs) and reimbursed between January 1998 and December 2002 by a Local Health Authority of Emilia Romagna (Ravenna district, 350,000 inhabitants). We selected subjects aged 40 years and older, permanently living in the area during the whole period of the study, who received their first prescription of antihypertensives between January and December 1999, with no prescription of antihypertensive agents in the previous year. For each patient, we documented the starting regimen and evaluated adherence to treatment in terms of persistence during the years (patients were defined persistent if they received at least one prescription per year) and in terms of daily coverage (patients were defined covered if they received an amount of drugs consistent with a daily treatment). Finally, switches or addition of other therapeutic classes during the 3-year period were identified. A cohort of 6,043 subjects receiving their first antihypertensive treatment in 1999 was obtained. Regarding the starting regimen, monotherapies with angiotensin converting enzyme inhibitors (n = 1,597; 26%) or calcium channel blockers (n = 1126; 19%) were the most frequently prescribed. Of the patients, 21% started with a drug combination regimen. Regarding adherence to treatment, 18% of the cohort received only one prescription throughout the 3 years, 13% received more than one prescription but stopped the therapy during the first year, 69% were persistent during the second year and 60% also during the third year. Only 34% were covered during the first year and 24% also during the second year, whereas only 20% of the patients resulted covered throughout the 3 years. Among persistent patients, 41% maintained the same antihypertensive regimen throughout the 3 years, 25% added other drugs to the initial treatment and 34% switched to completely different regimens. Our findings reflect the lack of convergence among guidelin