Simple Renal Cysts: Prevalence, Associated Risk Factors and Follow-Up in a Health Screening Cohort.

PURPOSE To investigate the prevalence of simple renal cysts in an adult health-screening cohort, and to evaluate clinical characteristics, associated risk factors and the natural course. MATERIALS AND METHODS Between April and November 2008, a thousand individuals diagnosed with simple renal cyst by ultrasonography in a check-up program were chart-reviewed for demographic-clinical characteristics and cyst features. Follow-up was done via electronic patient records. Univariate and multivariate analyses to evaluate the relationship of outcomes and correlation analysis were done to measure the degree of association between parameters. RESULTS The prevalence was 7.7%. There were 123 cysts in 77 patients, followed for 3.5 years (mean). Individuals with cysts were older (P < .01). Prevalence rates were 2.7% in individuals younger than 40 years and 23.9% in older than 60. The cysts were predominantly (94.8%) detected in males and most (63.6%) were solitary. No relation with Body Mass Index and total cholesterol levels was found but serum creatinine values were significantly increased in individuals with cysts (P < .01). There was no difference in the diagnosis of hypertension and microscopic hematuria in patients with renal cysts, however diabetes/hyperglycemia were more common and increasing age correlated with higher number of cysts (all P < .05). Follow-up revealed that the number of cysts were increased and/or the same in 86.5%; the sizes of cysts were larger and/or the same in 78.4% of patients, while in 14% of patients the cyst disappeared. CONCLUSION In a cohort of adults undergoing a health-screening, the prevalence of simple renal cyst was found 7.7% by ultrasonography. Renal cysts were more common in males and elders, and associated with increased levels of serum creatinine and diabetes.