Association between simple renal cyst and kidney damage in a Chinese cohort study

Background: The presence of simple renal cyst (SRC) has been associated to renal dysfunction, but the results were inconsistent. Accordingly, we conducted a longitudinal cohort study to explore the association between SRC and kidney damage. Methods: A total of 4274 adults (aged 45.4 ± 13.6 years) without chronic kidney disease at baseline were enrolled in 2008. SRC was assessed by ultrasonography. Logistic regression analysis were applied to explore the relationships between SRC and indicators of kidney damage (proteinuria and renal insufficiency), and also with relatively rapid decline in renal function (defined as the lowest quartile of △eGFR). Results: During 5 years of follow-up, participants in the SRC group had higher incidence of proteinuria (5.2% versus 2.4%, p = 0.004) and renal insufficiency (3.8% versus 0.97%, p < 0.001) compared with control group. SRC was correlated with proteinuria (OR 2.24; 95% CI 1.34–3.75) and renal insufficiency (OR 4.0; 95% CI 2.11–7.58) in univariable analysis, despite that the correlation was not significant after adjusted for traditional kidney disease risk factors. Furthermore, after adjusted for potential confounders, maximum diameter of the cyst (≥2.2 cm) was significantly associated with rapid decline in renal function (OR 2.19; 95% CI 1.24–3.87). Conclusions: Participants with SRC may be associated with higher incidence of proteinuria and renal insufficiency. This relationship may be obscured by age and other traditional risk factors. Higher diameter of the cysts contributed to more rapid decline in renal function of SRC participants.