Increased prevalence of simple renal cysts in patients with gout.

The aim of this study was to determine the prevalence of simple renal cysts in gout patients and evaluate associated risk factors for its development. Hundred and forty-six patients followed at our outpatient Gout Unit and 47 sex- and age-matched healthy kidney donors who had undergone routine renal ultrasonography, using a static gray scale and real-time B-mode units with a 3.5- or 5.0-MHz transducer, were evaluated for the presence of renal cysts. Demographic and clinical characteristics of gout patients were evaluated considering possible risk factors for the occurrence of simple renal cysts such as age, male gender, hypertension, and renal impairment. The prevalence of simple renal cyst was 26.0 % in gout patients and 10.6 % in control group (P = 0.045). Gout patients with simple renal cysts presented less renal lithiasis than those without this complication (5.2 vs 25.9 %; P = 0.003) in spite of an overall higher frequency of renal stones in gout patients compared to control group (20.5 vs. 6.3 %, P = 0.025). The presence of simple renal cyst in gout was not associated with previously reported factors such as age (P = 0.296), male predominance (P = 0.688), hypertension (P = 0.314), and renal impairment (P = 254). Moreover, no association with disease duration (P = 0.843) or tophi (P = 0.616) was observed. In conclusion, gout patients have an increased prevalence of simple renal cysts associated with a lower occurrence of nephrolithiasis. Whether renal cysts have any protective effect in the development of nephrolithiasis in gout remains to be determined.