A study, published in Rheumatology International, investigated the effect of a “treat-to-target” (T2T) approach to find the ideal dosage of xanthine oxidase inhibitors (XOIs) as a means to lower serum uric acid levels in patients with gout and stage 3 chronic kidney disease (CKD).* Their research found that this approach both conserved and improved renal function.

Background information

Gout is a form of inflammatory arthritis, usually characterized by a swollen joint, and attributed to elevated levels of uric acid in the blood (hyperuricemia). Previous studies have demonstrated a link between hyperuricemia—an excess of uric acid in the blood—and gout are linked to several comorbidities, including CKD.

Uric acid is a chemical that occurs when your body breaks down purines, which are both naturally occurring in the body, as well as in some foods and beverages, like beer, some fish, and dried beans and peas. An elevated level of uric acid in the body can come from a variety of factors, such as diet, weight, genetic factors, and other related diseases, and may lead to the accumulation of its crystals in the kidney—thus, causing kidney disease.

Gout is treated by anti-inflammatory drugs and medications that lower the blood’s uric acid level. Reducing uric acid below the saturation threshold causes the dissolution of the aforementioned crystals and the disappearance of the mechanism causing the disease. Due to limitations on the current recommended dosage of XOIs—allopurinol or febuxostat—doctors have been unable to properly use these medications to treat serum uric acid levels.

Research and investigation details

A group of Spanish researchers from Madrid and Barcelona investigated the association between glomerular filtration rate (GFR)—a test to measure renal function via creatinine levels—in gout patients with CKD using a T2T approach with XOIs. 

The T2T approach is based on three components:

• a target; 
• a method to determine if the target has been achieved; and 
• available treatment options in order to hit said target. 

For gout, there were two proposed targets:

• a level of uric acid lower than 6 mg/dl of uric acid for all patients, and
• a level of at least 5 mg/dl for patients with severe gout.

The multi-center study included patients diagnosed with gout and CKD stage 3, who were treated with XOIs for at least 12 months. The researchers’ T2T approach aimed to achieve uric acid levels lower than 5 to 6 mg/dl within six months of patients’ first visit.

Results and conclusions

Eighty-two percent (82%) of the study’s patients achieved the desired results, or target levels of lower serum uric acid in the blood. The patients’ improved renal function directly correlated to this reduction in uric acid.

The study’s authors concluded that using a T2T approach to reduce patients’ serum uric acid levels to an optimal level is possible and can help conserve and improve renal function in gout patients with stage 3 CKD.

Added insight can be found in Rheumatology Advisor’s article entitled, “Treat-to-Target Approach May Improve Renal Function in Patients With Gout and Chronic Kidney Disease.”

*Novella-Navarro, M., Cabrera-Alarcon, J. L., Diaz-Torne, C., Aramburu-Muñoz, F., et al. (2020, Jan. 25). “A treat-to-target approach for gout confers renoprotective effect in patients with chronic kidney disease stage 3.” Rheumatology International.