Background: Simple renal cysts are frequent findings in mid-aged people, their frequency increases with age. They are often detected by abdominal ultrasound and/or computed tomography during diagnostic procedures. Hypertension is also a frequent disease and its prevalence increases with age as well. The aim of our study was to evaluate the association between simple renal cysts and hypertension in a group of patients with normal renal function.
Patients and methods: Ninety-one patients (58 female and 33 male; mean age 50.5 +/- 16.9 years) were included in the study, all with normal renal function (serum creatinine <100 micromol/l). The patients were examined with a real-time ultrasound device with a 2-4 MHz convex transducer. Kidney size, presence, number and diameter of cysts were examined and the presence of hypertension was determined. The presence of hypertension was defined by the administration of antihypertensive agents, systolic blood pressure greater than 140 mmHg and/or diastolic blood pressure greater than 90 mmHg.
Results: Simple renal cysts were found in 19 (20.88%) patients. Only cortical cysts were found in 11 (12.09%) patients, only parapelvinic cysts were found in 4 (4.39%) patients. Four (4.39%) patients had cortical and parapelvinic cysts. Cortical cysts in both kidneys were found in five (5.49%) patients, parapelvinic cysts in both kidneys were found in three (3.29%) patients. Bilateral renal cysts were present in 10 (10.99%) patients, six (60%) of them had hypertension. We found no difference in the presence of simple renal cysts according to sex. Hypertension was detected in 30 (32.97%) patients. Hypertension was significantly more frequent in patients with simple renal cysts (P < 0.041) than in with patients without cysts. Simple renal cysts were also significantly associated with age (P < 0.01). With multiple regression analysis we found a significant association with age only (P < 0.0001), but not with hypertension (P = 0.394).
Conclusions: Simple renal cysts are frequent findings and their incidence increases with age. We found an association between simple renal cysts and hypertension. However, with multiple regression analysis only an association between simple renal cysts and age could be detected.