Antihypertensive medication use and blood pressure control: a community-based cross-sectional survey (ON-BP).

Background: The Ontario Blood Pressure (ON-BP) survey reported high treatment and control rates for hypertension in the province of Ontario, Canada, in a survey performed in 2006. This study examined patterns of utilization of antihypertensive drug classes and their impact on blood pressure (BP) control.

Methods: Cross-sectional, population-based survey of adults, 20-79 years of age (population 7,996,653). Responses are weighted to the Ontario hypertensive population of 1,498,045.

Results: Of all hypertensives, 51 and 49% were on monotherapy vs. 2+ drug therapy with similar control rates (86 vs. 80%, respectively). In those on monotherapy a renin-angiotensin system (RAS) blocker was the most commonly used drug class (62%) and use of other drug classes was only approximately 10%. In those on 2+ therapy, a RAS blocker was also the most common class (80%), followed by a diuretic (67%). In diabetics with hypertension 46 and 54% were on monotherapy vs. 2+ drug therapy with significantly higher control rates on monotherapy (90 vs. 46%). RAS blocker was also the most common drug class (85 and 80%, respectively), but in those on 2+ drugs only 45% were on a diuretic. Control rates did not differ by type of drug treatment in the overall hypertensive population and those with a comorbidity, but were low in diabetics on 2+ therapy and particularly in those on a calcium channel blocker (CCB) or diuretic.

Conclusions: High treatment and control rates of hypertension in Ontario are associated with high utilization of RAS blockers. Diabetics on 2+ therapy are the least effectively controlled, possibly reflecting the limited use of diuretics.