ECE2021 Audio Eposter Presentations Adrenal and Cardiovascular Endocrinology (80 abstracts)
Low-renin hypertension with normal or high aldosterone levels is a cause of severe hypertension, and can be diagnosed by applying endocrine society hyperaldosteronism guidelines
1Hospital Clínico San Carlos, Endocrinology and nutrition; 2Hospital Puerta del Hierro, Endocrinology and nutrition; 3Hospital Ramón y Cajal, Endocrinology and nutrition
Low-renin hypertension (LRH) with normal or elevated aldosterone levels is considered part of the spectrum of aldosterone-associated hypertension, and can cause poorly-controlled hypertension. We studied patients diagnosed with LRH, comparing their clinical and biochemical characteristics with patients diagnosed with primary hyperaldosteronism (PHA).
Methods
Retrospective. Diagnosis in a general Endocrinology out-patient clinic over 8 years, with strict application of Endocrine-Society Guidelines for PHA screening/diagnosis. Aldosterone/Renin (ARR) screening on medication, except for mineralocorticoid-receptor blockers or amiloride was positive when ≥ 20 (aldosterone and direct renin measured by Radioimmunoassay in pg/ml). Captopril challenge test (CCT) was positive for PHA on doxazosine and/or long-acting verapamil and/or hydralazine if aldosterone level ≥ 130 and/or ARR ≥ 50 2 hours post-25 mg captopril. Patients negative for PHA with normal/high basal CCT aldosterone, together with basal ARR ≥ 50 or low renin throughout CCT, were diagnosed with LRH. Clinical characteristics of both groups were compared. Parametric values expressed as mean (SD); non-parametric values as median [interquartile range]. SPSS 25.
Results
Diagnosis: 46 patients PHA, 80 LRH. Age at diagnosis: PHA: 57.0 (SD:11.2), LRH: 64.7 (SD:12.9), P = 0.001. PHA: 21/46 (46%) women, LRH: 16/80 (20%), P < 0.001.
Moderate hypertension
PHA: 21/46 (45.7%), LRH: 52/80 (65%), P = 0.04. Severe Hypertension: PHA 25/26 (54.3%), LRH: 28/80 (35%), P = 0.04. Resistant hypertension: PHA: 16/46 (34.8%) vs LRH: 5/80 (6.3%), P < 0.0001. All aldosterone and ARR levels were significantly higher in PHA than LRH, with screening and basal CCT values showing overlap. Renin levels were not significantly different at screening, nor throughout CCT. At screening, PHA vs LRH respectively: Aldosterone: 284.3 (SD:202.1) vs 206.11 (SD:99.3), P = 0.023. Renin: 3.8 (SD: 4.9) vs 5.2 (SD:4.6), P = 0.13. ARR: 109.9 (SD:8.5) versus: 52.9 (SD: 33.6), P < 0.0001. Baseline CCT: PHA vs LRHT respectively: Aldosterone 296.2 (SD: 194.5) vs 146.3 (SD:56.7), (P < 0, 001). Renin 3.0 (SD:3.7) vs 3.3 (SD: 2.15), P = 0.54. ARR: 162 (SD: 126.0) vs 57.7 (SD: 38.9). P < 0.001. 2-hour CCT: PHA vs LRH respectively: Aldosterone 221.57 (SD:117.3) vs 80.3 (SD 37.2), P < 0.001. Renin: 2.15 [1.25–4.0] vs 3.2 [2.2–4.8] P = 0.53. ARR: 69.3 [52.1–165.8] vs 22.6 [12.6–37.0], P = 0.001.
Conclusions
LRH can be diagnosed with the CCT when applying Endocrine-Society PHA guidelines. This entity was more frequent in a general Endocrinology out-patient clinic than PHA, and over a third of patients had severe HT. Given LRH’s previously-described favorable response to mineralocorticoid-receptor blockers, we believe that LRH should be diagnosed, and specifically treated as an aldosterone-associated hypertension.