The impact of side effects on hypertension management: a Japanese survey.

The purpose of this study was to assess medication compliance and to document side effects among a large number of Japanese patients receiving antihypertensive treatment. A total of 6289 patients being treated for hypertension returned completed questionnaires about their current blood pressure, therapy, side effects, and compliance with physicians' instructions. In addition, 4417 physicians returned completed questionnaires about their prescribing practices, side effects experienced by patients, and patient compliance. The antihypertensive agents they most often prescribed were calcium channel blockers, followed by angiotensin-converting enzyme inhibitors, beta-blockers, and diuretics. The proportion of patients who had well-controlled blood pressure, defined as systolic blood pressure < 160 mm Hg and diastolic blood pressure < 95 mm Hg, was similar regardless of the class of antihypertensive agent prescribed. Forty-nine percent of the patients with well-controlled blood pressure reported having at least one side effect while taking their current antihypertensive therapy, whereas a significantly greater percentage of patients (61%) with poorly controlled blood pressure reported side effects. Patients whose blood pressure was poorly controlled tended to have a higher incidence of most side effects than did those with well-controlled blood pressure. Also, the rate of intentional noncompliance was significantly higher in the group with poorly controlled blood pressure. In addition, the rate of noncompliance increased with the number of side effects reported. Although the causal relationship between side effects and non-compliance cannot be determined from this study, further investigation is warranted to better understand the impact these factors may have on overall cardiovascular morbidity and mortality.