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Recommendations Summary

CKD: Electrolytes: Potassium (2020)

Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.


  • Recommendation(s)

    CKD: Dietary Potassium Amount

    In adults with CKD 3-5D or posttransplantation, it is reasonable to adjust dietary potassium intake to maintain serum potassium within the normal range (OPINION).

    Rating: Consensus
    Conditional

    CKD: Dietary and Supplemental Potassium Intake for Hyperkalemia or Hypokalemia, CKD Post-Transplant

    In adults with CKD posttransplantation with either hyperkalemia or hypokalemia, we suggest that dietary or supplemental potassium intake be based on patient's individual needs and clinician judgement (OPINION). 

    Rating: Consensus
    Conditional

    CKD: Dietary and Supplemental Potassium Intake for Hyperkalemia or Hypokalemia, CKD 3-5D

    In adults with CKD 3-5D with either hyperkalemia or hypokalemia, we suggest that dietary or supplemental potassium intake be based on a patient’s individual needs and clinician judgment (2D).

    Rating: Weak
    Imperative

    • Risks/Harms of Implementing This Recommendation

      Potassium is widely distributed in foods but the main sources are fruits, vegetables, legumes and nuts. As these foods are major sources of fiber, vitamins, minerals and other important nutrients, efforts should be made to avoid  restricting dietary potassium. In particular reduced fiber can lead to constipation which could lower potassium excretion. For these issues, consult the guideline statements on fiber and fruit/vegetable intake.

    • Conditions of Application

      Special Discussions
      Research on this topic is complicated by the fact that potassium handling by the kidney will vary by disease state and CKD stage. In patients with pre-dialysis CKD the acute and chronic effects of dietary potassium loading are not consistently reflected in serum potassium levels due to compensatory mechanisms that are triggered to maintain homeostasis (Sterns et al 1979,  Alvestrand et al 1984, Hayes er al 1967).  Research and evidence on this area is also limited because of difficulties in obtaining reliable data on dietary potassium intake and absorption.

      Potassium binders bind potassium in the gut and prevent hyperkalemia. In theory, these medications could lead to a more liberalized diet in terms of potassium (i.e. fruits and vegetables). However, none of the pivotal trials examining potassium binders evaluated dietary potassium intake, and currently there is no known study that investigates how potassium intake should be modified when taking potassium binders. Since the focus of this guideline was dietary intake, rather than pharmalogical treatments, potassium binders were outside the scope of this guideline.  

      Implementation Considerations

      • Potassium is widely distributed in foods but the main sources are fruits, vegetables, legumes and nuts. As these foods are major sources of fiber, vitamins, minerals and other important nutrients, efforts should be made to avoid  restricting dietary potassium. In particular reduced fiber can lead to constipation which could lower potassium excretion. For these issues, consult the guideline statements on fiber and fruit/vegetable intake.
      • When treating hyperkalemia clinicians are advised to first try and identify contributing factors that can be corrected such as a hypoinsulinemic state or certain medications. This is true in light of the physiological benefits high potassium intake may confer, such as putative antihypertensive effects (Adrogue et al 2014). If hyperkalemia cannot be reversed the next step is to identify the most important dietary sources of potassium by interviewing the patient and dietary recalls. Clinicians preferably assisted by a renal dietitian should educate patients with hyperkalemia about fruits, vegetables, and other foods with low potassium content that ideally still contain higher levels of fiber and other micronutrients. Published food composition tables can be helpful in this regard (Cupisti et al 2018). In addition, potassium content in vegetables can be lowered by boiling and reductions in food taste and palatability associated with this strategy can be partially improved with the use of aromatic herbs (Burrowes et al 2006 and 2008).

    • Potential Costs Associated with Application

      There are no obvious costs to adjusting dietary potassium intake. 

    • Recommendation Narrative

      As the main intracellular cation potassium plays a major role mediating cellular electrophysiology, vascular function and BP, and neuromuscular function. High or low serum potassium levels have been associated with muscular weakness, hypertension, ventricular arrhythmias, and death. The influence of dietary potassium consumption on serum potassium content is therefore of great clinical relevance. Because the mechanisms involved in potassium homeostasis and excretion (i.e. adrenergic system, insulin, aldosterone, and urinary clearance) are commonly impaired in patients with CKD and ESRD hyperkalemia is an especially salient concern. Dietary potassium is the focus of these recommendations (potassium binders were outside the scope of the current guideline).

      There is a scarcity of studies on this topic and we found no data on how modifying diet can influence serum potassium in patients with CKD. The work group emphasizes that factors other than dietary intake influence serum potassium levels. These include medications, kidney function, hydration status, acid-base status, glycemic control, adrenal function, a catabolic state, or gastrointestinal (GI) problems like vomiting, diarrhea, constipation and bleeding. All these factors should be considered when formulating a strategy to keep the serum potassium within the normal range.

      The consequences of dietary potassium intake in patients with CKD are not known. Indeed, no studies were identified that directly examined the relationship between dietary potassium consumption and either serum levels or clinical outcomes. However, several studies used urine potassium excretion or other surrogates for dietary intake to assess the following outcomes. While we acknowledge that urine potassium excretion may not necessarily represent dietary potassium in these patients, the studies showed:

      Mortality
      Data on the association between dietary and urinary potassium excretion and mortality in adults with CKD were mixed. A study in MHD (stage 5), found that compared to the lowest quartile of dietary potassium intake (879 mg or 22.5 mEq/24hr) as measured by the Block Food Frequency Questionnaire, higher quartiles of intake were associated with a stepwise increase in risk of 5-year mortality (p-trend=0.03) (Noori et al 2010). Another study in pre-dialysis (Stage 2-4) there was no significant association noted between quartiles of urinary potassium excretion and all-cause mortality (He et al 2016). Compared to the highest quartile of urinary potassium excretion (mean 3600 mg or 92.1 mEq/24hr) persons in the three lowest quartiles had higher all-cause mortality (hazard ratio (95% CI) of 1.53 (1.15-2.02), 1.7 (1.25-2.31), 1.71 (1.23-2.38) for quartiles 3, 2, and 1, respectively).. Results remained similar even after using time-updated average urine potassium excretion (Leonberg-Yoo et al 2017).

      CKD Progression
      Data on the association between urinary potassium excretion and CKD progression in adults with CKD were mixed. In Stage 2-4; pre-dialysis urinary potassium excretion in the highest quartile (≥67.1 mmol or 2617 mg/24 h) was significantly associated with CKD progression (defined as incident ESRD or halving of eGFR from baseline) (1.59, 95% CI: 1.25-2.03) compared to levels in the lowest quartile (<39.4 mmol or 1541 mg/24 h) (He et al 2016). In another study in Stage 2-4; pre-dialysis, baseline urinary potassium excretion was not significantly associated with kidney failure (defined as dialysis therapy or transplantation) even when using time-updated average urine potassium (Leonberg-Yoo et al 2017).

      Nerve Function
      One randomized study examined the effects of dietary potassium restriction on progression of peripheral neuropathy in CKD patients. In 42 patients randomized to either dietary potassium restriction vs. usual diet (change in dietary potassium -854 vs. -343, p=0.35), potassium restriction was associated with stabilization of a neuropathy score (difference 0.4 ± 2.2, p<0.01) and several other nerve-related or general health scores over 24 months (Arnold et al 2017).

    • Recommendation Strength Rationale

      The evidence supporting the recommendation on individualizing potassium based on needs is based on Grade III /Grade D evidence. The remaining recommendations are based on Consensus/expert opinion. 

    • Minority Opinions

      Consensus reached.