Association between simple renal cysts and development of hypertension in healthy middle-aged men

Objectives: The temporal relationship between simple renal cysts and incident hypertension is unknown. In this study, we assessed the time-dependent relationship between simple renal cysts and incident hypertension in a cohort of healthy middle-aged men. Methods: A cohort study was conducted with data for 4516 healthy men with no evidence of hypertension at baseline. Study participants received a health checkup including abdominal ultrasonography between 2003 and 2004, and were followed in annual or biennial health examinations until May 2011. We matched groups with and without renal cysts by age. Results: Renal cysts were found in 123 participants (2.7%). The age-matched control group included 1476 men. Mean age of the cyst group did not differ from that of the control group (42.3 +/- 6.6 and 42.2 +/- 6.8 years, respectively; P = 0.939). SBP was lower in the cyst group than in the control group (118.0 +/- 13.2 and 120.5 +/- 12.2, respectively; P = 0.044). During 10 731.5 person-years of follow-up, 169 participants developed hypertension (1.6/100 person-years). Cumulative incidence of hypertension was higher in the cyst group than in the control group (29.9 and 15.4%, respectively; P = 0.000). After adjusting for confounding factors, renal cysts still significantly increased risk for hypertension (hazard ratio, 3.28; 95% confidence interval 2.24-4.80; P = 0.000). Age, BMI, mean arterial pressure and a family history of hypertension were also risk factors. Conclusion: Simple renal cysts independently predicted incident hypertension in this cohort of middle-aged men. Further research is justified to test the causal role of renal cysts in the development of hypertension.