Among 43 million hypertensive patients in Japan, blood pressure levels are controlled below 140/90mmHg in only a quarter of these patients. This fact may be due to poor adherence and inadequate lifestyles as well as “clinical inertia” (“diagnostic inertia” and “treatment inertia”) of health care providers.
Primary aldosteronism (PA) is the most common endocrine hypertension and often associated with resistant hypertension. Five to 10% of all people in hypertension and 20% of resistant hypertension is PA. Most importantly, PA presents with higher prevalence of cardiovascular diseases than essential hypertensive patients whose blood pressure levels are controlled to the similar levels. For the case-detection testing, high plasma aldosterone (PAC) to plasma renin activity (PRA) ratio is useful based on the clinical practice guideline of many countries. However, screening of PA is rarely done between 0.7% to 4.2% of hypertensive patients in daily clinical practice. This situation is a sad state of affairs (“diagnostic inertia”), and the screening of PA should be done at least once in all hypertensive patients. For treatment of PA, administration of a mineralocorticoid receptor blocker (MRB) is recommended in patients with bilateral PA as well as ones who do not willing to undergo surgery. It is therefore crucial to administer a MRB as a first-line therapy, although it is not included in the “first-line antihypertensives”.
In addition, since the PA screening test is done quantitatively, it may be insufficient to evaluate just “non-PA” when the ratio is lower than the cut-off values. It may be rather crucial to consider the pathogenesis as “borderline aldosteronism” or “mineralocorticoid receptor (MR)-associated hypertension” when the ratio is suboptimal, because a MR antagonist would be a better choice to control hypertension under such circumstances.
In diabetes mellitus and chronic kidney disease, MR may be directly overactivated by varied molecular mechanisms. In addition, under the treatment with angiotensin receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACEi) in patients with diabetes and chronic kidney disease, PAC is suppressed firstly, but re-elevated sometimes over baseline levels (“aldosterone breakthrough”). We therefore presume that combination treatment of a MRB with first-line antihypertensives (ARB/ACEi and calcium channel blocker) may resolve “treatment inertia” of hypertension. Considering the resolution of both “diagnostic and treatment inertia” for hypertension, it is conceivable that MRB should be included in the first-line therapy for hypertension.