Characteristics and significant predictors of detecting underlying diseases in adults with asymptomatic microscopic hematuria: a large case series of a Korean population.

OBJECTIVE: To provide detailed characteristics of asymptomatic microscopic hematuria, as well as to identify the significant predictors of detecting underlying diseases of asymptomatic microscopic hematuria, by evaluating a large Korean population.
METHODS: We obtained data from healthy adults over the age of 20 years who underwent the health-screening program from 2005 to 2010 at Seoul National University Bundang Hospital, resulting in 56,632 participants included in the analysis. Patients who had microscopic hematuria (five red blood cells/high-power field) were referred to a urological outpatient clinic for further urological evaluation. An underlying disease of asymptomatic microscopic hematuria was predefined as a urinary stone, renal mass, urothelial cancer or other relevant lesions.
RESULTS: At the initial urinalysis, 6.2% (3517/56,632) were diagnosed with asymptomatic microscopic hematuria. Of these, 1619 participants underwent repeat urinalysis within 1 year after screening, and 911 (56.3%) participants were detected with microscopic hematuria again. We identified 131 lesions (3.7%) as underlying diseases for asymptomatic microscopic hematuria, with urinary stone as the most common cause. Just six lesions were malignant: three renal cell carcinomas and three bladder cancers. Male sex and diabetes mellitus were significant predictors for detection of underlying diseases of asymptomatic microscopic hematuria.
CONCLUSIONS: Herein we report the largest screening case series of asymptomatic microscopic hematuria including approximately 60,000 asymptomatic participants studied at a single institution. These findings provide clinical practice information for the management of asymptomatic microscopic hematuria in adults.