Olmesartan clinical trial in Okinawan patients under OKIDS (OCTOPUS) study: design and methods

Background Guidelines for treatment of hypertension are not available for chronic hemodialysis (HD) population, despite the high mortality rate due to cardiovascular disease (CVD). Survival is much better among hypertensive patients than normal to hypotensive patients. Target levels of blood pressure and the class of antihypertensive drugs have not been examined in prospective studies. Methods We designed a prospective randomized controlled study among hypertensive HD patients in Okinawa (Okinawa Dialysis Study, OKIDS). The outcomes will be compared between two treatment regimens, such as (1) renin–angiotensin system (RAS) inhibitor Olmesartan and others, and (2) antihypertensive drugs without RAS inhibitors, in a parallel fashion. The title of the study is Olmesartan Clinical Trial in Okinawan Patients under OKIDS (OCTOPUS). Outcomes are any cause of death and CVD in 3 years in a total of 462 patients. Subjects are age 20–79 years and ambulatory on thrice weekly HD treatment. Eligible patients have resistant hypertension: pre-HD session blood pressure 140/90 mmHg and over for more than 1 month regardless with the use of antihypertensive drugs. Patients treated with RAS drugs are eligible if they continue to be hypertensive for more than 1 month after switching to non-RAS antihypertensive drugs. Conclusion This study provides evidence for the target levels of blood pressure at a pre-HD session and the impact of RAS inhibitors. We also evaluate the usefulness of home blood pressure monitoring in HD patients.