The prevalence of low-renin hypertension not meeting the diagnostic criteria for primary aldosteronism is 26.4% in primary care patients with treatment-naïve hypertension, a Victorian study suggests.
The finding may open up the promise of renin-guided individualised treatment for a significant minority of patients with hypertension.
The study, published in the Journal of the Endocrine Society [link here], screened 261 patients with treatment-naïve hypertension for primary aldosteronism (PA) with plasma aldosterone and direct renin concentrations.
It found 52.1% of the cohort had normal renin hypertension (direct renin concentration ≥10 mU/L), 26.4% had low-renin hypertension (direct renin concentration <10mU/L) and 18.0% had PA (aldosterone-to-renin ratio ≥70 pmol/mU and confirmed with saline suppression test).
“Compared to the normal renin hypertension group, those with low-renin hypertension had more female patients (68.1% versus 49.3%, p=0.031) and were older (57.1±12.8 years versus 51.8±14.0 years p=0.022),” said the study authors from the Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, Melbourne.
“Possible mechanisms underlying the decrease in renin with age include reduced renal mass and/or 11-beta-hydroxysteroid dehydrogenase 2 enzyme function, the appearance of aldosterone-producing adrenal cell clusters with age and/or impaired responsiveness to baroceptor-and renal beta1-adrenergic receptor stimulation.”
The investigators said this raised the question of whether it would be more appropriate to have age-specific reference ranges for renin and thresholds for the classification of low-renin hypertension.
They said a recent systematic review and meta-analysis [link here] had shown that mineralocorticoid receptor antagonists (MRAs) were more effective in lowering blood pressure in low-renin hypertension than ACEi/ARBs.
“Given that two-thirds of people with hypertension require two or more antihypertensives to achieve adequate blood pressure control and that compliance is inversely related to the number of medications prescribed, a personalised treatment method based on a now readily available biomarker is certainly attractive compared with the current add-on treatment strategy,” they said.
“As renin measurements become more accessible in routine clinical care, further research is warranted to explore the role of renin-guided personalised antihypertensive treatment in primary care with the potential to benefit a large number of people.”
“Such a strategy may lead to reduced medication burden and therefore improved compliance, better blood pressure control and reduced long-term sequelae of hypertension.”
The study was led by Monash Health endocrinologist Dr Sonali Shah, a PhD candidate at the Hudson Institute of Medical Research, with senior investigator Associate Professor Jun Yang, also from Monash and the Hudson Institute.