From the Guidelines
Having just one kidney can potentially lead to higher uric acid levels due to reduced kidney function or filtration capacity. When you have only one kidney, that single kidney must handle the entire filtration workload normally shared by two kidneys, which can reduce the overall efficiency of uric acid excretion. Uric acid is a waste product that needs to be filtered by the kidneys and eliminated through urine. With reduced kidney function or filtration capacity, uric acid may accumulate in the bloodstream, resulting in elevated levels. This is particularly concerning for individuals who already have risk factors for hyperuricemia (high uric acid), such as a diet high in purines (found in red meat, organ meats, and certain seafood), obesity, or certain medications.
According to the 2020 American College of Rheumatology guideline for the management of gout 1, considerations for patients with chronic kidney disease (CKD) should be taken into account, as higher starting doses and CKD are associated with risk of allopurinol hypersensitivity syndrome. However, this guideline does not directly address the relationship between having one kidney and uric acid levels.
In contrast, the KDIGO consensus report on autosomal dominant tubulointerstitial kidney disease 1 provides more relevant information, suggesting that patients with certain kidney diseases, such as UMOD-associated disease, are more likely to develop gout and may benefit from allopurinol therapy. Additionally, the report recommends liberal water intake to compensate for possible urinary concentration defects and avoiding nonsteroidal anti-inflammatory drugs, which can worsen kidney function.
While the medical management of kidney stones guideline 1 provides information on the use of allopurinol for patients with recurrent calcium oxalate stones and hyperuricosuria, it does not directly address the relationship between having one kidney and uric acid levels.
If you have a single kidney and are concerned about uric acid levels, it's advisable to:
- Maintain good hydration (at least 2-3 liters of water daily)
- Limit alcohol consumption
- Reduce purine-rich foods in your diet
- Maintain a healthy weight
- Regularly monitor kidney function and uric acid levels through blood tests Medications like allopurinol or febuxostat may be prescribed if uric acid levels remain persistently elevated, but these should only be taken under medical supervision as they require careful dosing in people with reduced kidney function.
From the Research
Uric Acid and Kidney Function
- The kidneys play a crucial role in regulating serum uric acid levels, with approximately two-thirds of uric acid produced in humans being excreted by the kidneys 2.
- Abnormal serum levels of uric acid are due to alterations in production or excretion, and fractional excretion of uric acid can help determine the underlying etiology of hypouricemia or hyperuricemia 3.
Hyperuricemia and Kidney Disease
- Hyperuricemia is seen when kidney function declines, and elevated uric acid levels may play a role in the initiation and progression of kidney disease 4.
- Observational studies suggest a relationship between uric acid levels and incident chronic kidney disease (CKD), but the evidence is conflicting 4.
- Some studies suggest that lowering uric acid levels may retard the progression of CKD, and that uric acid may be an important factor in the pathogenesis of acute kidney injury (AKI) and CKD 3, 5.
Having One Kidney and Uric Acid Levels
- There is no direct evidence to suggest that having one kidney will lead to high uric acid levels.
- However, having one kidney may affect the body's ability to excrete uric acid, potentially leading to hyperuricemia 3, 2.
- Further studies are needed to clarify the association between uric acid and kidney disease, particularly in individuals with a single kidney 4, 2.
Treatment of Hyperuricemia in CKD
- Febuxostat, a novel xanthine oxidase inhibitor, has been shown to effectively reduce serum uric acid concentrations and may suppress the progressive decline in renal function in patients with CKD 5, 6.
- Allopurinol, another uric acid-lowering therapy, has also been used to treat hyperuricemia in CKD patients, but its effectiveness in retarding kidney disease progression is less clear 6.