STEPPED CARE FOR HYPERTENSION - ARE THE ASSUMPTIONS VALID

Objective To examine whether the choice of initial antihypertensive me dication is associated with patient withdrawal from therapy among a la rge cohort of newly diagnosed hypertensive individuals receiving medic al care in actual practice. Design The records of the outpatient presc ription drug plan of Saskatchewan, Canada, were searched for individua ls with a diagnosis of essential hypertension who were receiving at le ast one antihypertensive drug between January 1989 and December 1994. Persistence was defined, and records were classified by class of initi al antihypertensive agent prescribed. Subjects In all, the records of over 79 000 individuals with a diagnosis of hypertension and an antihy pertensive drug prescribed between 1990 and 1994 were evaluated. Persi stence with therapy was considered in a subset of newly diagnosed pati ents, observed for at least 6 months, and receiving an initial prescri ption from one of four major categories of antihypertensive agents. Re sults Among newly diagnosed patients, diuretics and angiotensin conver ting enzyme (ACE) inhibitors were the most common initial medication. ACE inhibitors were associated with the highest persistence rates afte r 1 year of follow-up (83%), followed by calcium antagonists (81%), di uretics (78%) and beta-blockers (74%) (P < 0,001). These results were unchanged in a Cox proportional hazards model which controlled for con founding by age, sex and proxy measures for prior health status. Concl usions A significant proportion of newly diagnosed patients withdraw f rom therapy within the first year, and this withdrawal seems to be rel ated to the choice of initial antihypertensive agent. These results su ggest that recommendations for using stepped care in hypertension mana gement may not be optimal if the initial agent prescribed is associate d with decreased levels of persistence with therapy.