Elevated Serum Uric Acid Associated With Negative Outcomes After Transplant

Hyperuricemia, a significant risk factor for gout, is associated with cardiovascular disease and its comorbidities. Elevated serum uric acid (SUA) levels also have potential effects on kidney transplant outcomes.

Hyperuricemia is associated with graft failure and death among kidney transplant recipients (KTRs). Living kidney donor KTRs with heightened SUA levels are at higher risk for return to dialysis, retransplantation, and death from graft failure. However, some studies have suggested that SUA levels are not an accurate predictor of allograft function.

Kian Djamali and colleagues hypothesized that higher SUA levels are associated with negative outcomes after kidney transplantation, including cardiovascular events (CVEs). In a study published in Kidney360, they assessed the potential association between SUA levels and CVEs following kidney transplantation and other composite outcomes.

Using data from the Wisconsin Allograft Recipient Database, they evaluated all adult KTRs from January 1, 2000 to December 31, 2019. Kidney-only transplant recipients who maintained a functioning allograft without CVEs before the earliest SUA level measurement 5 to 13 months after transplant were eligible for the study.

A total of 3,808 patients were followed for a median of 7.5 after their transplants. Of those, 81% were White, 40% were female, and the mean (SD) age was 51 (13) years. The researchers analyzed survival regarding CVEs, CVE-related mortality, death-censored graft failure, and uncensored graft failure within 10 years after transplantation.

Transplant recipients with elevated SUA levels early after transplant had worse outcomes. Those with SUA levels greater than 6.8 mg/dl after transplant had a significantly higher risk for congestive heart failure (CHF) than those with SUA levels less than 6 mg/dl (adjusted hazard ratio [aHR], 1.55; 95% CI, 1.10-2.19; P=0.01), uncensored graft failure (aHR, 1.18; 95% CI, 1.02-1.36; P=0.03), and death-censored graft failure (aHR, 1.28; 95% CI, 1.01-1.61; P=0.04), after adjustment for variables including kidney graft function.

However, no statistically significant association between SUA levels and other CVEs was observed, and there was no statistically significant risk for other outcomes of interest when comparing SUA levels less than 6 mg/dl with SUA levels of 6 to 6.8 mg/dl. The researchers acknowledged that the overall relationship between SUA levels and cardiovascular disease still appears to be inconclusive.

Nonetheless, the findings suggest that SUA levels are associated with CHF, uncensored graft failure, and death-censored graft failure, and may be a predictor of poor outcomes among KTRs.

“While more robust studies are needed to identify SUA targets for KTRs, our data suggest that achieving a SUA level of 6.8 mg/dl or less may reduce the risk of uncensored graft failure, DCGF [death-censored graft failure], and CHF,” the authors noted.

Source: Kidney360