New Data Links Renal Transplant with Gout Comorbidity

While it is known that gout is a comorbidity for kidney transplant patients, the precise proportion of renal transplant patients developing gout and the time period this occurs is unclear.

A team, led by Brian LaMoreaux, MD, medical director at Horizon Therapeutics, presented data at the Clinical Congress of Rheumatology (CCR) West 2019 annual meeting in San Diego, CA, from a large, mixed-insurance, US population database to determine gout prevalence in the renal transplant population, as well as to determine when gout occurs in patients relative to receiving a renal transplant.

The investigators performed a retrospective review of private and Medicare data for approximately 22.5 million patients from 2007-2017 to identify kidney transplant patients with at least 6 months in plant prior to transplant and at least 6 months in plant following the transplant.

The diagnosis of gout in kidney transplant patients was also evaluated in relationship to the time of kidney transplant.

Of the 22.5 million patients in the database, 571,462 had a diagnosis of gout and 6082 had a kidney transplant and at least 6 months in plan both pre-transplant and post-transplant.

Of the kidney transplant patients, 1505 had a gout diagnosis, 908 of which suffered from gout prior to the transplant and 597 patients with a gout code only after transplant.

“This retrospective analysis demonstrates that kidney transplant patients commonly suffer from gout both before and after transplant,” the authors wrote.

The investigators also found a small subset of patients with serum uric acid (sUA) levels prior to or post-transplant.

While pre-transplant sUAs were similar between groups with mean sUA ranging from 6.92-7.33 mg/dl, overall mean sUA levels decreased after transplant, with the exception of those who went on to develop gout post-transplant.

“As expected, gout was a common comorbidity in renal transplant patients, occurring in 25% of the overall transplant population at some point,” the authors wrote.

The investigators found that 15% of the patients undergoing renal transplant had gout prior to transplant, with another 10% developing new-onset gout an average of 1.79 years after transplantation.

Patients who receive kidney transplants are often at an increased risk for developed disorders like hyperuricemia and gout. This risk is generally attributed to the frequent use of calcineurin inhibitors—cyclosporine and tacrolimus.

Post-transplant medication use was also similar in the population gout to those that did not develop gout post-transplant. The only exception to this was for tacrolimus and cyclosporine.

The team said additional studies are needed, including an increased focus on screening and treatment of gout in the renal transplant population.