FP323MICROSCOPIC HEMATURIA IS A RISK FACTOR OF INCIDENT CHRONIC KIDNEY DISEASE IN THE GENERAL POPULATION: A COMMUNITY-BASED PROSPECTIVE COHORT STUDY

INTRODUCTION AND AIMS: Although asymptomatic microscopic hematuria (MH) is a common finding in clinical practice, its long-term outcome remains unknown. This study evaluated the clinical implication of MH in the general population using a large-scale long-term longitudinal cohort database. METHODS: This prospective observational cohort study included 8719 participants from the Korean Genome and Epidemiology Study between 2001 and 2014. MH was defined as ≥5 red blood cells per high-power field in random urinalysis without evidence of pyuria. The primary study outcome measure was incident chronic kidney disease (CKD), defined as estimated glomerular filtration rate (eGFR) <60 mL min-11.73m-2. RESULTS: The mean age was 51.7±8.8 years, and 4201 (48.2%) were men. The average baseline eGFR was 93.0±13.1 mL min-11.73m-2. During a median follow-up of 11.7 years, subjects with MH were more likely to develop proteinuria [odds ratio (OR), 11.99; 95% confidence interval (CI), 6.80-21.13; P<0.001] and urologic cancer (OR, 7.01; 95% CI, 2.39-20.56; P<0.001), whereas risk of diabetes mellitus was not different between groups. CKD occurred in 677 (7.8%) subjects. In Cox regression after adjustment for multiple confounders, subjects with MH had a significantly higher risk of incident CKD than those without [hazard ratio (HR), 1.45; 95% CI, 1.12-1.87; P=0.005]. Isolated MH without proteinuria was also a risk factor of incident CKD (HR, 1.37; 95% CI, 1.04-1.79; P=0.023) and the risk was further increased in MH with concomitant proteinuria (HR, 5.41; 95% CI, 2.54-11.49; P<0.001). In propensity score matching (PSM) analysis after excluding subjects with proteinuria, the cumulative CKD incidence was significantly higher in subjects with isolated MH than in those without (P=0.013). In the PSM matched cohort, multivariable stratified Cox regression analysis revealed that subjects with isolated MH had a significantly higher risk of incident CKD than those without (HR, 1.83; 95% CI, 1.14-2.94; P=0.012). CONCLUSIONS: The presence of MH is associated with an increased risk of incident CKD in the general population. Therefore, attentive follow-up is warranted in persons with MH for early detection of CKD.