Recommendations on nutritional intake of potassium in CKD: it's now time to be more flexible!

Associations Between Dietary Potassium Intake From Different Food Sources and Hyperkalemia in Patients With Chronic Kidney Disease

OBJECTIVE

Previous studies reported mixed results on associations between dietary potassium intake and hyperkalemia in patients with chronic kidney disease (CKD). This study investigated the association between potassium intake from different food sources and hyperkalemia in patients with non-dialysis-dependent CKD.

METHODS

A total of 285 patients were recruited at a university hospital and 2 city hospitals in Tokyo. Dietary potassium intake was estimated by a validated diet history questionnaire. Associations of potassium intake from all foods and individual food groups with serum potassium were examined by multivariable linear regression among potassium binder nonusers. An association between tertile groups of potassium intake and hyperkalemia, defined as serum potassium ≥5.0 mEq/L, was evaluated by multivariable logistic regression.

RESULTS

Among 245 potassium binder nonusers, total potassium intake was weakly associated with serum potassium (regression coefficient = 0.147, 95% confidence interval (CI): 0.018-0.277), while an association with hyperkalemia was not observed (first vs third tertile: adjusted odds ratio = 0.98, 95% CI: 0.29-3.26). As for food groups, potassium intakes from potatoes, pulses, and green/yellow vegetables were positively associated with serum potassium. Patients in the highest tertile of potassium intake from potatoes had higher odds of hyperkalemia as compared to those in the lowest tertile (adjusted odds ratio = 4.12, 95% CI: 1.19-14.34).

CONCLUSION

Total potassium intake was weakly associated with serum potassium, but not with hyperkalemia. Potassium intake from potatoes was associated with hyperkalemia. These findings highlight the importance of considering food sources of potassium in the management of hyperkalemia in CKD.

Recommendations for the management of hyperkalemia in patients receiving renin-angiotensin-aldosterone system inhibitors

Hyperkalemia is common in clinical practice and can be caused by medications used to treat cardiovascular diseases, particularly renin-angiotensin-aldosterone system inhibitors (RAASis). This narrative review discusses the epidemiology, etiology, and consequences of hyperkalemia, and recommends strategies for the prevention and management of hyperkalemia, mainly focusing on guideline recommendations, while recognizing the gaps or differences between the guidelines. Available evidence emphasizes the importance of healthcare professionals (HCPs) taking a proactive approach to hyperkalemia management by prioritizing patient identification and acknowledging that hyperkalemia is often a long-term condition requiring ongoing treatment. Given the risk of hyperkalemia during RAASi treatment, it is advisable to monitor serum potassium levels prior to initiating these treatments, and then regularly throughout treatment. If RAASi therapy is indicated in patients with cardiorenal disease, HCPs should first treat chronic hyperkalemia before reducing the dose or discontinuing RAASis, as reduction or interruption of RAASi treatment can increase the risk of adverse cardiovascular and renal outcomes or death. Moreover, management of hyperkalemia should involve the use of newer potassium binders, such as sodium zirconium cyclosilicate or patiromer, as these agents can effectively enable optimal RAASi treatment. Finally, patients should receive education regarding hyperkalemia, the risks of discontinuing their current treatments, and need to avoid excessive dietary potassium intake.

Potassium and Hypertension: A State-of-the-Art Review

Hypertension is the single most important and modifiable risk factor for cardiovascular morbidity and mortality worldwide. Non pharmacologic interventions, in particular dietary modifications have been established to decrease blood pressure (BP) and hypertension related adverse cardiovascular events. Among those dietary modifications, sodium intake restriction dominates guidelines from professional organizations and has garnered the greatest attention from the mainstream media. Despite guidelines and media exhortations, dietary sodium intake globally has not noticeably changed over recent decades. Meanwhile, increasing dietary potassium intake has remained on the sidelines, despite similar BP-lowering effects. New research reveals a potential mechanism of action, with the elucidation of its effect on natriuresis via the potassium switch effect. Additionally, potassium-substituted salt has been shown to not only reduce BP, but also reduce the risk for stroke and cardiovascular mortality. With these data, we argue that the focus on dietary modification should shift from a sodium-focused to a sodium- and potassium-focused approach with an emphasis on intervention strategies which can easily be implemented into clinical practice.

RAASi Therapy Attenuates the Association between 24-h Urinary Potassium Excretion and Dietary Potassium Intake in CKD Patients

The aim of this study was to evaluate urinary potassium (K) excretion as a reliable marker of dietary K intake, in a cohort of CKD patients with or without Renin-Angiotensin-Aldosterone System (RAAS) inhibitor therapy. One hundred and thirty-eight consecutive out-patients (51 f and 87 m) aged 60 ± 13 years and affected by CKD stage 3-4, who were metabolically and nutritionally stable, entered the study between November 2021 and October 2022. No difference was observed between patients with (n = 85) or without (n = 53) RAAS inhibitor therapy, regarding dietary intakes, blood biochemistry, and 24-h urine excretion parameters. Considering all patients, urinary K showed a weak relationship with eGFR (r = 0.243, p < 0.01), and with dietary K intake (r = 0.184, p < 0.05). Serum K was not associated with dietary K intake, but an inverse relationship was observed with eGFR (r = -0.269, p < 0.01). When patients were examined depending on whether they were receiving RAAS inhibitor therapy, the weak inverse relationship between serum K and eGFR was maintained in both groups. Conversely, urinary K excretion remained positively associated with dietary K intake only in the no RAAS inhibitor group. In conclusion, 24-h urine K excretion may be used as a surrogate of K intake, but RAAS inhibitor therapy reduces the association between 24-h urine K excretion and dietary K intake in CKD patients.