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22-08-2011 | General practice | Article

Traces of blood in urine linked to future end-stage renal disease


Free abstract

MedWire News: Persistent asymptomatic microscopic hematuria detected during adolescence and early adulthood is strongly associated with the development of end-stage renal disease (ESRD) in the future, research shows.

Such ESRD is primarily of glomerular etiology, but the researchers note that the overall incidence and absolute risk for developing the condition is low.

"Persistent asymptomatic isolated microscopic hematuria is a frequent incidental finding on routine examination of children and young adults" explain Asaf Vivante (Edmond and Lily Safra Children's Hospital, Tel Hashomer, Israel) and colleagues.

Little is known about the impact of such findings, so Vivante and team used data from over 1.2 million people aged 16-25 years (60% male), examined for fitness for military service in Israel between 1975 and 1997, to evaluate the risk for treated ESRD in adolescents and young adults with persistent asymptomatic isolated microscopic hematuria.

Overall, 3690 (0.3%) individuals were diagnosed with persistent asymptomatic isolated microscopic hematuria by urinary dip-stick test and urine microscopy.

Of those, 26 (0.7%) were treated for ESRD during 22 years of follow-up, compared with 539 (0.05%) individuals without persistent microscopic hematuria, to give respective incidence rates of 34.0 and 2.1 cases per 100,000 person-years.

After accounting for age, gender, paternal country of origin, year of enrollment, body mass index, and blood pressure at baseline, the researchers found that the risk for ESRD was 18.5 times higher in people with persistent microscopic hematuria than in those without it.

When Vivante and team looked at specific ESRD etiologies, they observed a 32-fold increased risk for ESRD attributed to primary glomerular disease among the individuals with persistent microscopic hematuria compared with those without the condition. The respective incident rates of primary glomerular disease-associated ESRD for these patients were 19.6 and 0.55 cases per 100,000 person-years.

"Our findings suggest that persistent asymptomatic isolated microscopic hematuria detected during adolescence and young adulthood is an early marker for primary glomerular injury and may be the first sign of an occult renal disease," write the researchers in JAMA.

"As such, there may be a window during which the diagnosis of asymptomatic isolated microscopic hematuria following urine screening can provide an alert to the future development of symptoms or renal failure," they add.

The team concludes by calling for future studies to evaluate the utility of population screening for persistent asymptomatic isolated microscopic hematuria in improving clinical outcomes.

In an accompanying editorial, Robert Brown from the Beth Israel Deaconess Medical Center in Boston, Massachusetts, USA said that the study findings suggest that assessment of microscopic hematuria in young adults could be added to the assessment of albuminuria in middle-aged and older adults as a tool for the early detection of chronic kidney disease.

"Thus, it appears that the time may have arrived for routine urine dipstick screening in adolescents and adults, at least at all initial examinations and perhaps every 5 to 10 years thereafter," he concluded.

By Laura Dean

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