Persistent Microscopic Hematuria Linked to Higher ESRD Risk

Laurie Barclay, MD

August 23, 2011

August 23, 2011 — Persistent microscopic hematuria in adolescents and young adults is linked to higher long-term risk for end-stage renal disease (ESRD), according to the results of a retrospective, population-based study reported in the August 17 issue of the Journal of the American Medical Association.

"Persistent asymptomatic isolated microscopic hematuria is a frequent incidental finding on routine examination of children, adolescents, and young adults," write Asaf Vivante, MD, from the Edmond and Lily Safra Children's Hospital in Tel Hashomer, Israel, and colleagues. "The most recent American Academy of Pediatrics guidelines rescinded the recommendation for urine screening during the second decade of life.... Few data are available on long-term outcomes among adolescents and young adults with persistent asymptomatic isolated microscopic hematuria."

The study cohort consisted of 1,203,626 persons 16 to 25 years old (60% men) who were examined between 1975 and 1997 for fitness for military service. Through linkage to the Israeli-treated ESRD registry, the investigators identified incident cases of ESRD treated from January 1, 1980, to May 31, 2010.

Among individuals with persistent asymptomatic isolated microscopic hematuria, the hazard ratio (HR) of treated ESRD was estimated with Cox proportional hazards models. Onset of treated ESRD was defined as the date of beginning dialysis or the date of renal transplantation, whichever came first. Mean follow-up duration was 21.88 ± 6.74 years.

Of 1,203,626 eligible persons in the study cohort, 3690 (0.3%) had persistent asymptomatic isolated microscopic hematuria (0.4% in men and 0.2% in women). During follow-up, 26 individuals (0.70%) with and 539 (0.045%) without persistent asymptomatic isolated microscopic hematuria went on to have treated ESRD. Incidence rates were 34.0 and 2.05 per 100,000 person-years, respectively, and the crude HR was 19.5 (95% confidence interval [CI], 13.1 - 28.9).

The risk for ESRD linked to persistent asymptomatic isolated microscopic hematuria was similar (HR, 18.5; 95% CI, 12.4 - 27.6) in a multivariate model adjusted for age, sex, paternal country of origin, year of enrollment, body mass index, and baseline blood pressure. Compared with persons without hematuria, those with persistent asymptomatic isolated microscopic hematuria had a dramatically higher risk for treated ESRD caused by primary glomerular disease (incidence rates, 19.6 vs 0.55 per 100,000 person-years; HR, 32.4; 95% CI, 18.9 - 55.7). However, the absolute risk was low, with the proportion of treated ESRD attributed to microscopic hematuria being 4.3% (95% CI, 2.9% - 6.4%).

"Presence of persistent asymptomatic isolated microscopic hematuria in persons aged 16 through 25 years was associated with significantly increased risk of treated ESRD for a period of 22 years, although the incidence and absolute risk remain quite low," the study authors write.

Limitations of this study include low generalizability to other populations, termination of follow-up before the study population reached the age at which ESRD peaks, and inability to determine the effectiveness of mass screening for microscopic hematuria in children and young adults.

In an accompanying editorial, Robert S. Brown, MD, from Beth Israel Deaconess Medical Center in Boston, Massachusetts, discusses the inclusion of dipstick testing for hematuria as part of routine screening for young adults.

"The study by Vivante et al suggests that assessment of microscopic hematuria in young adults may be added to assessment of albuminuria in adults middle-aged and older as a tool to detect CKD [chronic kidney disease] early and potentially minimize its high costs and morbidity," Dr. Brown writes. "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. The assessment of the available evidence by the US Preventive Services Task Force should help provide clinicians with additional guidance about the role of urine dipstick screening in prevention of CKD."

Access to anonymized databases was provided by the Israel Defense Forces Medical Corps and the Israeli Ministry of Health. The study authors and Dr. Brown have disclosed no relevant financial relationships.

JAMA. 2011;306:729-736, 764-765.

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