Microscopic hematuria, especially if it persists, is associated with an increased risk for chronic kidney disease (CKD), a new study finds.

“Our study suggests that individuals with prolonged hematuria should be monitored, and that they may be candidates for early preventive strategies to decrease the risk of subsequent CKD,” investigators concluded in a paper published in the American Journal of Kidney Diseases.

Investigators assessed the presence of microscopic hematuria (at least 5 red blood cells per high powered field) across 2 consecutive health care visits. Among 232,220 Korean adults (aged 18 years and older) without kidney disease or malignancy at baseline, incident CKD developed in 2392.

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Investigators defined CKD as an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2 or proteinuria 1+ or higher on a urine dipstick test.

On multivariable analysis, men with microscopic hematuria that regressed, developed, or persisted over 2 visits had a significant 2.8-, 4.4-, and 8.3-fold increased risk for CKD, respectively, over 4.8 years of follow-up compared with men with no hematuria, Seungho Ryu, MD, PhD, of Sungkyunkwan University School of Medicine in Seoul, South Korea, and colleagues reported. Women with microscopic hematuria that developed or persisted had a significant 2.5- and 3.9-fold increased risk for CKD, respectively. Microscopic hematuria that regressed did not significantly increase CKD risk.

The investigators adjusted the models for age, smoking status, body mass index, history of diabetes, hypertension, and cardiovascular disease, eGFR, and other factors. In women, they considered the influence of menstrual cycle and menopause status.

In subgroup analyses, the associations between hematuria and CKD were significantly stronger in individuals  younger than 40 years compared with older adults and in current smokers. Among individuals with persistent hematuria, those younger than 40 years had a 6.8-fold increased risk for CKD, whereas those aged 40 years or older had a 4.5-fold increased risk.  Current smokers had a 7.5-fold increased risk for CKD, whereas those who were not current smokers had a 4.4-fold increased risk.

“Further studies are necessary to test whether hematuria, especially persistent hematuria, can help identify both men and women at high risk of CKD and whether appropriate management of hematuria can help decrease subsequent CKD risk and progression to renal failure,” Dr Ryu’s team wrote.

The investigators acknowledged that results from a Korean population may not apply to other ethnicities. The study was limited by the lack of data on patients’ albuminuria levels and CKD etiologies.


Um YJ, Chang Y, Kim Y, et al. Risk of CKD following detection of microscopic hematuria: a retrospective cohort study. Am J Kidney Dis. Published online November 4, 2022. doi:10.1053/j.ajkd.2022.09.012