Allopurinol treatment is not associated with increased mortality in patients with gout and chronic kidney disease even at 5 years after starting treatment, a study has found.
Around one in five patients with gout also have chronic kidney disease, and previous research suggests that hyperuricemia is itself a contributor to renal disease, which is why there has been interest in the use of serum urate–lowering medication in patients with both conditions.
Since the publication of two earlier randomized controlled trials suggested a twofold increase in mortality among patients with renal disease who were treated with allopurinol in an attempt to slow progression, there has been wariness about the drug in patients with compromised renal function.
In a study published in Annals of Internal Medicine, Jie Wei, PhD, of Xiangya Hospital at Central South University in Changsha, China, and coauthors report the results of their retrospective, population-based study of 5,277 adults aged 40 and older with gout and moderate to severe chronic kidney disease who were initiated on allopurinol and 5,277 matched individuals not on allopurinol.
At 5 years after the patients started allopurinol, the study found that mortality was a statistically significant 15% lower (hazard ratio, 0.85; 95% confidence interval, 0.77-0.93) among those on allopurinol, compared with those not taking the drug. The rate was 4.9 deaths per 100 person-years among those on allopurinol, compared with 5.8 among those not taking it.
The researchers also created two simulated randomized clinical trials from the data for initiators of allopurinol, replicating each initiator twice. The first trial assigned patient replicates either to achieving a target serum urate level of less than 0.36 mmol/L within a year or not achieving it. The second assigned patient replicates to either an allopurinol dose-escalation group or no dose escalation.
For the target serum urate level study, 1,484 achieved the target, and this was associated with a 13% lower hazard ratio for mortality that just missed statistical significance (HR, 0.87; 95% confidence interval, 0.75-1.01).
In the dose-escalation study, there were 773 participants who increased their dose of allopurinol in the first year after initiation – from a median of 100 mg/day to a median final dose of 300 mg/day – and 2,923 who didn’t. Those who escalated their dose had a nonsignificant 12% lower risk of mortality (HR, 0.88; 95% CI, 0.73-1.07), compared with those who didn’t.
The authors suggest that this could be the result of confounding, as patients who achieved target serum urate levels may have been of better health generally than those who didn’t, which could also have contributed to lower mortality.
Coauthor of the study Yuqing Zhang, DSc, of Massachusetts General Hospital and Harvard Medical School, Boston, said there had previously been a theory that allopurinol could protect against progression of renal disease. However, the two randomized, controlled trials in patients with chronic kidney disease but not gout published in 2020 suggested that allopurinol was instead associated with a doubling of mortality in this group.
“This study really shows convincing evidence that among gout patients with renal disease, allopurinol does not increase mortality,” Dr. Zhang told this news organization. He suggested the reason that the earlier studies had found higher mortality among patients on allopurinol was because those patients did not have gout. Given that gout can increase mortality, treating it effectively with allopurinol may therefore reduce mortality even in patients with concurrent chronic kidney disease.
Commenting on the study, Angelo Gaffo, MD, from the Birmingham VA Medical Center and the division of rheumatology at the University of Alabama at Birmingham, said that, while there had been data suggesting increased mortality, the findings from this “very well-done” study were reassuring and even suggested a possible decrease in mortality associated with allopurinol.
“I wouldn’t scream it out loud because it needs confirmation, but it’s something also that we have a sense that could be true,” he said.
Dr. Gaffo noted that patients treated with allopurinol tended to be those with fewer comorbidities. “Patients who have a lot of comorbidities probably are less likely to have their dose of allopurinol started or increased because of some concerns that practitioners may have about putting them on another medicine or increasing the dose of that medicine,” he said.
He also stressed that the findings still need replication in other large database studies, given that a prospective, randomized clinical trial addressing such a question would be difficult to conduct.
The study was supported by the Project Program of National Clinical Research Center for Geriatric Disorders, the National Natural Science Foundation of China, and the U.S. National Institutes of Health. Two authors reported consulting fees from the pharmaceutical sector unrelated to the study. No other conflicts of interest were declared.
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