From the Guidelines
Having just one kidney can potentially lead to higher uric acid levels due to the increased workload on the remaining kidney to filter waste products, including uric acid. When you have only one kidney, the remaining kidney has to work harder to filter waste products from your blood, including uric acid. This increased workload may reduce the kidney's efficiency in eliminating uric acid, causing levels to rise in the bloodstream. Additionally, if the remaining kidney has any impairment or reduced function, this can further compromise uric acid excretion. People with a single kidney should monitor their uric acid levels regularly through blood tests. If levels become elevated, dietary modifications may help, such as reducing intake of purine-rich foods (red meat, organ meats, seafood, beer) and increasing water consumption to help flush uric acid through the kidneys. In cases of significantly elevated uric acid, medications like allopurinol or febuxostat might be prescribed to reduce uric acid production, as suggested by the 2020 American College of Rheumatology guideline for the management of gout 1. The connection between kidney function and uric acid levels exists because approximately two-thirds of uric acid elimination occurs through the kidneys, so any reduction in kidney function or number can impact this process. Some key considerations for managing uric acid levels in patients with kidney disease include avoiding diuretics, which can aggravate hyperuricemia, and using liberal water intake to compensate for possible urinary concentration defects, as recommended in the KDIGO consensus report on autosomal dominant tubulointerstitial kidney disease 1. It's also important to note that allopurinol can be effective in reducing the risk of recurrent calcium oxalate stones in patients with hyperuricosuria and normal urinary calcium, as demonstrated in a prospective randomized controlled trial 1. Overall, managing uric acid levels is crucial for individuals with a single kidney, and a combination of dietary modifications, regular monitoring, and medication can help mitigate the risk of elevated uric acid levels. Some key points to consider include:
- Monitoring uric acid levels regularly through blood tests
- Reducing intake of purine-rich foods and increasing water consumption
- Avoiding diuretics and using liberal water intake
- Considering medication like allopurinol or febuxostat to reduce uric acid production
- Being aware of the potential benefits and risks of different treatments, as outlined in the relevant guidelines and studies 1.
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.