The MUSCAT study: A multicenter PROBE study comparing the effects of angiotensin II type-1 receptor blockers on self-monitored home blood pressure in patients with morning hypertension: Study design and background characteristics

Elevated morning home blood pressure (MHBP) has been reported to have a close relationship to cerebrocardiovascular events and hypertensive target organ damages, and hence is regarded as a predictor of cardiovascular events. However, there is no evidence that lowering of MHBP can improve morbidity, mortality or target organ damage. In recent guidelines, angiotensin II type-1 receptor blockers (ARBs) are recommended as the first-choice drugs for antihypertensive therapy. Pharmacological characteristics differ among ARBs, and some are suggested to have greater efficacy in lowering MHBP than others. In preparation for the MUSCAT study, we surveyed both self-monitored MHBP and office blood pressure (OBP) in 1,234 patients with essential hypertension. Among them, 367 patients had diabetes mellitus (DM) and 229 suffered from chronic kidney disease (CKD). More than 64% (n=790) of patients had morning hypertension. In MUSCAT, we will investigate: the different effects of four ARBs (losartan, candesartan, valsartan, and telmisartan) in patients with morning hypertension, with a focus on the drugs' MHBP-lowering efficiency. Secondly, we will evaluate the different actions of the four ARBs on cardiovascular surrogate markers, such as the brachial-ankle pulse wave velocity, high-sensitive C-reactive protein level, and urinary albumin excretion/creatinine ratio. Patients will be randomized into four arms, and given one of the four "sartans" once daily for 12 months. MHBPs and surrogate markers will be examined at baseline and after 1 year of follow-up. In the stratified analysis, we will determine the significance of MHBP reduction on cardiovascular risk management.