Gout is present in nearly one third of Americans with severe chronic kidney disease (CKD), according to a study.
In addition, the prevalence of gout is higher among patients with lower average estimated glomerular filtration rates (eGFRs) or higher levels of albuminuria, even after adjusting for uric acid levels.
“Two take-home points for nephrologists are that there is a high prevalence of gout among persons with kidney disease, and that albuminuria is associated with a higher prevalence of gout. While the latter association has been previously described, I think the magnitude we uncovered is noteworthy,” said first author Stephen Juraschek, an MD-PhD student in epidemiology at Johns Hopkins University in Baltimore. He and his colleagues published their findings online ahead of print in Seminars in Arthritis and Rheumatism.
Juraschek, together with Allan C. Gelber, MD, PhD, of the Johns Hopkins School of Public Health, and others based their findings on an analysis of data from 15,132 adult participants in the National Health and Nutrition Examination Surveys (NHANES) from 1988-1994 and 2007-2010.
In both NHANES timeframes, approximately 1%-2% of subjects with eGFRs of 90 mL/min/1.73 m2 or higher had gout compared with 30% among participants with eGFRs below 30. The team observed a similar pattern for albuminuria, even after adjusting for factors such as age, sex, race/ethnicity, hypertension, body mass index, and diabetes.
They also found an overall 2.7% prevalence of gout among Americans in the 1988-1994 timeframe and of 3.7% in 2007-2010. In both periods, the researchers observed an inverse relationship between the proportion of individuals with a reduced eGFR and with gout or hyperuricemia, and a direct relationship between increased albuminuria and gout or hyperuricemia.
In addition, in both NHANES timeframes, the mean eGFR for subjects with gout was 76-82, compared with 97-102 for subjects without gout, in both NHANES timeframes. Furthermore, the median albumin-to-creatinine ratio among those with gout was approximately 10 mg/g compared with 6 mg/g among those without gout.
“We found that incremental changes in GFR, albuminuria and CKD are associated with a higher prevalence of gout,” Juraschek said. “These findings were not merely relegated to persons with severe CKD. And they also persist even after accounting for multiple risk factors associated with both CKD and gout, including levels of uric acid. Uric acid is arguably the most important mediator of gout, yet our findings show that there is a relationship between kidney disease and gout that is independent of uric acid.”
He and his co-investigators believe health practitioners treating CKD patients with new-onset joint pain or swelling should be vigilant for undiagnosed gout, while physicians treating patients with gout should be wary of CKD as an underlying factor contributing to both hyperuricemia and gout risk, since many urate-lowering medications require renal dosing or have associated nephrotoxicity.