Highlights
- Low-normal sodium (LNS) intake is associated with a significantly higher risk of heart failure (HF) and cardiovascular (CV) death in patients with type 2 diabetes (T2D) and chronic kidney disease (CKD).
- Canagliflozin selectively mitigates the increased CV risk seen in individuals with low-normal sodium intake, effectively flattening the risk gradient.
- The renal protective effects of canagliflozin remain consistent regardless of whether a patient has high or low-normal dietary sodium intake.
- These findings suggest that SGLT2 inhibitors may provide a physiological buffer against the adverse cardiorenal effects typically associated with salt restriction in vulnerable populations.
Background
Sodium-glucose cotransporter 2 (SGLT2) inhibitors have redefined the management of type 2 diabetes (T2D) and chronic kidney disease (CKD) by providing robust protection against heart failure (HF) and kidney failure. However, the interplay between dietary sodium—a traditional pillar of cardiovascular and renal management—and the natriuretic mechanism of SGLT2 inhibitors remains complex. While high sodium intake is a known driver of hypertension and albuminuria, excessively restricted sodium intake has also been paradoxically linked to adverse cardiovascular outcomes, potentially due to over-activation of the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system.
In the context of CKD and T2D, managing sodium is particularly delicate. The CREDENCE trial (Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation) established the efficacy of canagliflozin in reducing cardiorenal events. This post hoc analysis by Chiriacò et al. seeks to clarify whether dietary sodium levels modify the therapeutic benefit of canagliflozin, providing critical insights for personalized nutrition and pharmacological therapy.
Key Content
Methodology of the Post Hoc Synthesis
Researchers utilized data from 2573 participants of the CREDENCE trial who had available urinary sodium measurements. Daily sodium intake was estimated using a validated formula. Participants were stratified into two cohorts: the low-normal sodium group (LNS; <158 mmol/day or ~3.6 g/day) and the high sodium group (HS; ≥158 mmol/day). The median follow-up period was 2.6 years.
The primary outcome was a composite of cardiovascular death or hospitalization for heart failure (HHF). Secondary outcomes included HHF alone, a composite renal outcome (end-stage kidney disease, doubling of serum creatinine, or renal death), and all-cause mortality. Cox proportional hazards models were adjusted for age, sex, baseline eGFR, and albuminuria.
The Low-Sodium Paradox in Placebo Recipients
In the placebo arm, patients in the LNS group exhibited a significantly higher risk of the primary cardiovascular composite compared to the HS group (adjusted HR 1.56; 95% CI 1.10, 2.23). Continuous modelling further illustrated a near-linear rise in the risk of heart failure and cardiovascular death as sodium intake levels decreased. This suggests that in the absence of SGLT2 inhibition, aggressive sodium restriction may be counterproductive or indicative of a frailer phenotype in patients with advanced CKD.
Canagliflozin as a Cardioprotective Modulator
Canagliflozin demonstrated a striking interaction with sodium intake. In the LNS group, canagliflozin reduced the risk of CV death or HHF by 52% (adjHR 0.48; 95% CI 0.33, 0.70). Conversely, in the HS group, the effect on this specific CV composite was not statistically significant (adjHR 1.05; 95% CI 0.73, 1.53).
This differential impact highlights that canagliflozin’s cardioprotective benefits are most pronounced in patients who are otherwise at high risk due to low sodium levels. By “flattening” the risk gradient, canagliflozin appears to stabilize the hemodynamic and neurohormonal fluctuations associated with lower sodium intake.
Consistency in Renal Protection
Unlike the cardiovascular outcomes, the renal benefits of canagliflozin were uniform. The drug significantly reduced the composite renal outcome risk in both the LNS and HS groups. Furthermore, dietary sodium intake itself did not significantly alter the risk of renal progression in the placebo group. This suggests that while sodium intake is a major determinant of acute cardiovascular stability, canagliflozin’s intra-renal mechanisms—such as the restoration of tubuloglomerular feedback—function effectively regardless of systemic sodium load.
Expert Commentary
Mechanistic Rationale: The Hemodynamic Buffer
From a translational perspective, the findings by Chiriacò et al. align with the emerging “smart natriuretic” profile of SGLT2 inhibitors. In low-sodium states, the body typically responds by increasing RAAS activity and sympathetic tone to maintain blood pressure, which can exacerbate heart failure. SGLT2 inhibitors, however, may counteract this by reducing sympathetic activity and improving myocardial energetics without triggering the massive compensatory RAAS activation seen with potent loop diuretics.
Alignment with KDIGO 2024/2025 Perspectives
Recent insights from the KDIGO Controversies Conference emphasize the bidirectional relationship between the heart and kidney. The conference highlighted that small, initial declines in eGFR after starting SGLT2 inhibitors are hemodynamic rather than structural, reflecting a reduction in intraglomerular pressure. The CREDENCE post hoc analysis reinforces this by showing that even if salt intake is low (potentially reducing plasma volume), the renal protective effect of SGLT2 inhibitors remains intact without causing excessive acute kidney injury.
Clinical Applicability and Guidelines
Clinicians should interpret these findings as a call for a more nuanced approach to dietary sodium. While the WHO and various guidelines recommend sodium reduction to prevent hypertension, this study suggests that for T2D patients with established CKD, very low sodium intake might increase heart failure vulnerability. Importantly, initiating an SGLT2 inhibitor like canagliflozin provides a safety net, protecting these patients from the cardiovascular risks of a low-sodium environment while preserving their kidneys.
Conclusion
This post hoc analysis of the CREDENCE trial provides pivotal evidence that canagliflozin mitigates the increased cardiovascular risk associated with low-normal sodium intake in patients with T2D and CKD. While high sodium intake remains a concern for general population health, the LNS phenotype in CKD patients represents a high-risk group that specifically benefits from SGLT2 inhibition. Crucially, the renal benefits of canagliflozin are universal across the spectrum of sodium intake. Future research should focus on prospective trials to determine the optimal sodium “sweet spot” for patients on SGLT2 inhibitors and whether these findings extend to other agents in the class.
References
- Chiriacò M, Tricò D, Giannoni A, et al. Impact of canagliflozin on the cardiorenal effects of dietary sodium intake in type 2 diabetes: a post hoc analysis of the CREDENCE trial. Diabetologia. 2026; PMID: 41817689.
- Kidney Disease: Improving Global Outcomes (KDIGO). Kidney disease and heart failure: recent advances and current challenges. Kidney Int. 2028; PMID: 41791738.
- Perkovic V, Jardine MJ, Neal B, et al. Canagliflozin and Renal Outcomes in Type 2 Diabetes and Nephropathy. N Engl J Med. 2019;380(24):2295-2306. (Original CREDENCE Trial).
