There has been substantial evidence from clinical trials to support the rationale of use of thiazide diuretics in patients with essential hypertension. Diuretics may be more effective in reduction of blood pressure in Japanese patients than Caucasian because of higher salt intake. Moreover, given a large number of hypertensive population here, diuretics may be the most cost-effective antihypertensive agent. Japanese physicians, however, tend to avoid diuretics even in elderly hypertensive patients because of much concern over metabolic adverse events including new onset diabetes, which is deemed to increase cardiovascular risk. Although it is unlikely that use of low dose (12.5 mg of HCTZ or less) diuretics is associated with metabolic adverse events when they are given with any other appropriate antihypertensive agents (e.g. Ca antagonist, ACE inhibitor, ARB, K sparing diuretics) other than β-blockers, the researchers have to confirm the safety of low dose diuretics in terms of new onset diabetes in Japanese, who are assumed to be "diabetes prone" based upon thrifty gene hypothesis.