Redefining the Renin-Aldosterone Axis: From Categorical Diagnosis to a Continuous Spectrum of Cardiorenal Risk

Highlights

• Evidence from a nationwide Danish cohort of 12,650 adults demonstrates that renin-independent aldosterone production (RIAP) confers a continuous risk for rapid kidney function decline and MACE.
• The risk of rapid eGFR loss (≥5 mL/min/1.73 m² per year) is significantly elevated at an ARR as low as 27.7 pmol/mIU, well below common diagnostic cutoffs for primary aldosteronism (PA).
• Targeted mineralocorticoid receptor antagonist (MRA) therapy and aldosterone suppression are associated with improved nocturnal
  **Synthesizing Research Findings**

  I’m now integrating the Ljungberg data with related studies, especially the JAMA review, to clarify the risk continuum. The key is demonstrating risk *below* current diagnostic thresholds, shifting the focus towards continuous risk, not just categorical PA. I will also incorporate the data on Hypertension action bundles. The JSON structure is evolving to reflect these nuanced relationships.
  blood pressure patterns and reduced cardiovascular mortality.

• Current diagnostic frameworks requiring strict suppression testing are being challenged in favor of a spectrum-based approach to metabolic and vascular management.

Background

Primary aldosteronism (PA) has long been considered a binary diagnosis—present or absent—based on rigid biochemical thresholds and suppression testing. However, emerging evidence suggests that the deleterious effects of aldosterone on the heart and kidneys do not respect these arbitrary cutoffs. Renin-independent aldosterone production (RIAP) contributes significantly to target organ damage through mineralocorticoid receptor overactivation, leading to fibrosis, oxidative stress, and impaired vascular compliance. Despite its prevalence in up to 20% of patients with resistant hypertension, PA remains critically underdiagnosed, with fewer than 2% of affected individuals receiving a formal diagnosis in some settings. There is an urgent need to re-evaluate the renin-aldosterone profile not just as a diagnostic tool for a specific endocrine disorder, but as a continuous biomarker of cardiorenal risk.

Key Content

The Continuous Risk Gradient: Insights from the 2026 Danish Cohort

A pivotal nationwide cohort study by Ljungberg et al. (2026), involving 12,650 adults with hypertension, provides robust evidence for the continuous nature of aldosterone-mediated risk. Over a median follow-up of 3.6 years, the study found that higher aldosterone-to-renin ratios (ARR) were linearly associated with adverse outcomes. Notably, the adjusted hazard ratio (aHR) for rapid kidney function decline was 1.27 at an ARR of 27.7 to 70.0 pmol/mIU, rising to 2.66 for an ARR >138.7 pmol/mIU. Interestingly, while the risk for rapid eGFR decline manifested at lower ARR levels, the risk for major adverse cardiovascular events (MACE) and overt kidney failure became statistically significant primarily at higher ARR thresholds, suggesting that the kidney may be more sensitive to sub-diagnostic aldosterone excess.

Cardiovascular and Circadian Implications

The cardiovascular burden of aldosterone excess extends beyond simple pressure effects. Recent research (2026) highlights the link between aldosterone and the loss of physiological nocturnal blood pressure decline (non-dipping). In a study of 681 patients with PA, log-transformed aldosterone concentrations were inversely associated with nocturnal systolic BP decline. Crucially, achieving biochemical remission via targeted hormonal suppression—such as selective adrenal arterial embolization—restored the “dipper” pattern in nearly 40% of patients. This mechanistically links aldosterone excess to circadian rhythm disruption, a known driver of MACE. Furthermore, network meta-analyses of 43 randomized trials confirm that MRAs are superior to ARBs and direct renin inhibitors (DRIs) in reducing MACE, particularly in patients with heart failure or renal comorbidities (RR 0.82; 95% CI 0.75-0.90).

Renal Progression and Secondary Hypertension

The relationship between aldosterone and renal outcomes is particularly pronounced in resistant hypertension. Systematic screening in specialized clinics reveals that PA accounts for approximately 17% of apparently resistant hypertension (aRH). While patients with true resistant hypertension (RAH) without an endocrine cause often show faster eGFR decline (an additional 0.7 mL/min/1.73 m² per year), those with PA remain at high risk for albuminuria and thrombotic microangiopathy (TMA). In patients with biopsy-proven malignant hypertension-associated TMA, the use of renin-angiotensin-aldosterone system (RAAS) inhibitors was associated with a 55% reduction in the risk of progressing to end-stage renal disease (ESRD).

Evolving Diagnostic and Therapeutic Paradigms

The clinical community is increasingly questioning the utility of traditional suppression tests. Critical appraisals (2026) argue that because PA exists on a continuous biochemical spectrum, it is scientifically impossible to draw a single diagnostic threshold. Moreover, assay uncertainty often leads to contradictory results during oral salt or saline suppression. Simultaneously, implementation studies like the “hypertension action bundle” have shown that training general practitioners and specialists can increase the detection of PA by fourfold, shifting the focus from identifying hypokalemia to recognizing refractory cases, pre-eclampsia history, and hypertension in young adults.

Expert Commentary

The shift from a categorical to a continuous model of aldosterone-mediated risk has profound implications for clinical practice. If risk begins at ARR levels far below current diagnostic thresholds, many “essential” hypertensive patients may benefit from MRA therapy (e.g., spironolactone or eplerenone) long before they meet formal criteria for PA. This is supported by the 2026 JAMA review on resistant hypertension, which advocates for early spironolactone use (25-50 mg/d) to achieve significant SBP reductions (-13.3 mm Hg).

However, challenges remain. Cortisol co-secretion, often seen in bilateral macronodular adrenal disease (up to 52% of cases), adds a layer of metabolic complexity that MRAs alone may not address. Additionally, the role of SGLT2 inhibitors in this population is emerging; meta-analyses suggest they provide synergistic renal protection when added to standard RAAS inhibition, reducing the primary composite of kidney failure or CV death by 24% (OR 0.76). Clinicians must balance these benefits against potential risks, such as hyperkalemia, particularly in patients with baseline eGFR <45 mL/min/1.73 m².

Conclusion

The evidence from 2024–2026 indicates that the renin-aldosterone profile is a high-fidelity barometer of cardiorenal health rather than a simple diagnostic switch for primary aldosteronism. As the risk of rapid kidney decline and MACE scales linearly with RIAP, the traditional reliance on salt suppression testing may be nearing obsolescence. Future guidelines should likely emphasize early risk stratification based on ARR gradients and the broader implementation of MRAs and SGLT2 inhibitors to mitigate the continuous risk of cardiorenal progression in hypertensive populations.

References

• Ljungberg C, et al. Renin-Aldosterone Profiles and Cardiorenal Outcomes in Hypertension: A Nationwide Cohort Study. J Am Coll Cardiol. 2026; PMID: 41879574.
• JAMA Review. Diagnosis and Management of Resistant Hypertension: A Review. JAMA. 2026; PMID: 41870448.
• Drugs Network Meta-analysis. Efficacy of RAAS Inhibitors on Cardiovascular Outcomes in Hypertensive Population. Drugs. 2026; PMID: 41843385.
• Am J Hypertens. Is It Time to Retire Aldosterone Suppression Testing? Am J Hypertens. 2026; PMID: 40887827.
• J Am Heart Assoc. Aldosterone and Impaired Nocturnal Blood Pressure Decline in Primary Aldosteronism. JAHA. 2026; PMID: 41804894.