Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp ith progressive aging of the population and an increasing prevalence of hypertension and diabetes mellitus, chronic kidney disease (CKD) remains a worldwide public health problem. As many patients with CKD die of cardiovascular (CV) disease before reaching endstage renal disease, measures against CKD should be undertaken from the viewpoint of improving their prognosis. 1,2Left ventricular hypertrophy (LVH) is a manifestation of target organ damage and an independent risk factor for CV morbidity and mortality. 3,4 Several studies have examined the association of renal dysfunction with LVH and have reported that reduced renal function and albuminuria are risk factors for it. 5-7 LVH is thus common in patients with CKD, indicating kidney -heart interaction. To date, however, few studies have examined the impact of LVH on renal function in hypertensive patients. 8,9 Our previous subanalysis of the CASE-J trial reported that cardiac complications, including LVH and ischemic heart disease, were independent predictors of CV events, but not of renal events. 10 In contrast, Boner et al reported that LVH was associated with a significantly increased risk of not only CV events but also the progression of kidney disease in patients with type 2 diabetes and nephropathy. 9 Of 4,703 patients in the CASE-J trial, only 46 (1.0%) experienced a renal event, a much smaller proportion than the 32.9% in the RENALL study, indicating that the CASE-J trial lacked sufficient statistical power to evaluate the impact of LVH on renal events.In this context, the present study was conducted as a subanalysis of the CASE-J trial aimed at investigating the impact of LVH on the time-course of renal function in highrisk Japanese hypertensive patients. Background: In this subanalysis of the CASE-J, which was conducted to compare the effects of candesartan and amlodipine in Japanese high-risk hypertensive patients, the association of left ventricular hypertrophy (LVH) with renal function is clarified.