4. At the screening visit, patients should either be untreated for at least 4 weeks or taking a stable drug regimen for at least 4 weeks. Medical treatment can consist of all major drug classes. This includes diuretics, beta-blockers, alfa-blockers, calcium-channel blockers (CCBs), inhibitors of the renin system (angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II type 1 receptor blockers (ARBs), the direct renin inhibitor aliskiren,18 aldosterone receptor antagonists (ARAs), centrally acting antihypertensive drugs and vasodilators (hydralazine). In line with current recommendations and recent studies, unless contra-indicated or not tolerated, aldosterone antagonists, such as spironolactone 25 to 50 mg per day should have been attempted for at least 4 weeks to improve blood pressure control in treatment-resistant patients. (1) The patients should be intellectually and emotionally capable of measuring their blood pressure at home and accept to keep a diary (control group) or to have a report sent to their doctor (intervention group).