Current status of antihypertensive prescription and associated blood pressure control in Japan.

The importance of tight blood pressure (BP) control has been established. We performed cross-sectional studies on the current status of BP control and the prescription and efficacy of antihypertensive drugs in hypertensive patients in Japan. The data were also evaluated in subgroups with or without diabetes mellitus (DM) and in winter and summer. Analyses were performed on the collected data of 12,437 treated hypertensive patients in winter and 5,972 in summer 2002. In winter, 50.3% of patients received calcium channel blockers (CCBs), 15.3% received angiotensin converting enzyme inhibitors (ACEIs) and 11.0% received angiotensin receptor blockers (ARBs). In the patients receiving monotherapy, 69% of patients received a CCB, 13% an ACEI and 11.0% an ARB. A total of 2,918 patients received combination therapy, and CCBs were the most frequently (89.6%) prescribed component of such therapy. Prescriptions of beta-blockers (BBs) decreased and those of CCBs and diuretics (D) increased with age (p<0.001). The rate of patients with adequately controlled BP less than 140/90 mmHg was 40.3% in the CCB group, 37.6% in the D group, and 36.9% in the BB group (p<0.001). In patients receiving combination therapy, those with CCB+D had the best rate of BP control (40.7%). The rate of patients with adequately controlled BP was lower in winter than in summer at both a target BP of 140/90 mmHg (36.2% vs. 43.8%, p<0.001) and a target BP of 130/85 mmHg in patients younger than 60 years old (15.5% vs. 18.6%, p<0.02). In diabetic patients, the target BP (130/80 mmHg) was achieved in only 11.3%, which was lower (p<0.05) than the rate in non-diabetic patients (13.1%). In conclusion, the present cross-sectional study showed that CCBs were the most frequently prescribed agent for the treatment of hypertension in Japan. The rate of adequate BP control was less than 50% and was even worse in patients with DM and in winter. Our results indicate that physicians should treat hypertension more intensively to achieve the target BP.