The relationship between simple renal cysts and glomerular filtration rate in the elderly.

PURPOSE: This cross-sectional study aimed to examine the association between the presence of simple renal cyst and glomerular filtration rate (GFR) in a group of elderly patients.

METHODS: This study included 207 elderly subjects residing in a nursing home. All subjects underwent ultrasonography examination as well as serum urea and creatinine measurements. Creatinine clearance was calculated according to Cockroft-Gault formula. In addition, demographic data were recorded.

RESULTS: Sixty-six subjects had simple renal cysts, and cysts were more frequent among male patients (43.1 vs. 28.2 %, p = 0.047). In addition, patients with renal cysts were slightly older and had a slightly lower GFR. On the other hand, patients with or without renal cysts did not differ with regard to renal sizes. In univariate analysis, reduced GFR was associated with older age (81.2 ± 5.9 vs. 75.7 ± 5.1 years, p < 0.001) and was more frequent among females (69.2 vs. 52.9 %, p = 0.034). In addition, lower BMI, presence of cyst, lower mean renal length, and lower mean renal thickness were associated with impaired GFR (p < 0.05 for all); however, number or bilaterality of the cysts were not linked with deterioration of GFR. Multivariate analysis identified only female gender (OR 2.4, 95 % CI 1.1-5.1, p = 0.030), a small BMI (<25; OR 6.2, 95 % CI 2.4-15.5, p < 0.001), and advanced age as independent predictors of low GFR. Each year increase in age results in OR 1.2 (95 % CI 1.1-1.3, p < 0.001).

CONCLUSION: Presence of simple renal cyst does not seem to have an effect on the decline in GFR in elderly patients. Age-related increase in the incidence of renal cysts appears to occur in geriatric population.