Risk of Kidney Stones Up 60% In Some Gout Patients

A recent study showed that patients with gout face a 60% higher risk of nephrolithiasis (NL) than the general population. Additional risk factors for NL include male sex, diabetes, and obesity in patients with gout, and male sex and kidney disease in the general population.

NL is known to be associated with gout. However, less data exists on the risk and risk factors for NL in patients with gout compared with the general population.

In their study, the researchers evaluated 29,968 patients with gout and 138,678 age- and sex-matched controls. Patient data was obtained through the regional health care database in western Sweden (VEGA). The researchers followed patients from January 1, 2006, or upon their first diagnosis of gout, until patients’ death, emigration, or December 31, 2012.

The researchers analyzed socioeconomic factors as well as risk factors for first-time NL, including comorbidities and current medication use. Incidence calculations were performed for patients with gout, regardless of prior NL diganosis, and controls. Hazard ratios with the first occurrence of NL as the outcome were calculated only in patients without previous NL diagnosis.

Results indicated that 678 NL events had occurred among patients with gout, compared with 2125 events among controls. Most point estimates for predictive factors were similar between gout patients and controls. However, the researchers found a significant interaction for losartan, which increased the risk of NL only in controls. Loop diuretics significantly decreased the risk of NL in both patients with and without gout by 30% to 34%.

The researchers found that further significant predictors of NL included male sex, diabetes, and obesity among gout patients, and male sex and kidney disease among controls.

“The risk (age and sex adjusted) of NL was increased by 60% in cases compared to controls,” the researchers concluded. “None of the commonly used medications increased the risk of NL in gout patients.”

—Christina Vogt

Reference:

Landgren AJ, Jacobsson LTH, Lindström U, et al. Incidence and risk factors for nephrolithiasis in patients with gout and the general population, a cohort study [Published online July 24, 2017]. Arthritis Res Ther. https://doi.org/10.1186/s13075-017-1376-z.