Huang Z., Zhang J., Chen B., Li D., You X., Zhou Y., Qiu W., Ding X., Chen C.: Clinical Significance of Persistent Hematuria Degrees in Primary IgA Nephropathy: A Propensity Score-Matched Analysis of a 10-Year Follow-Up Cohort. American Journal of Nephrology DOI 10.1159/000529650
Persistent high-grade hematuria is associated with an adverse impact on prognosis in IgA Nephropathy (IgAN), independent of proteinuria according to retrospective observational studies. But this association has not been rigorously examined prospectively, especially in randomized controlled intervention trials, so we are not very well informed on the potential clinical utility of directing management at minimizing hematuria (compared to the volumes of information concerning proteinuria.
Huang and co-workers re-examined this issue in a single-center, retrospective propensity-matched cohort study of 684 patients with biopsy-proven IgA N. The propensity match was performed using age, sex and eGFR, but not proteinuria. High-grade hematuria was defined as ≥ 330 erythrocytes per μL of urine.
These findings are largely confirmatory and may not be generalizable as they were conducted in a single center in China.
Nevertheless, they support the notion that persistent hematuria is an often neglected aspect of prognostication in IgAN. It is not a part of the International IgAN risk tool, perhaps because it is correlated with the morphological aspects of IgAN as assessed by the Oxford-MEST scoring system. The findings indicate that hematuria’s response to intervention is an important finding that should be monitored along with proteinuria and perhaps that hematuria should be examined as an end-point of treatment independent of proteinuria.
This is not an easy task as quantitation of hematuria needs to be performed on-site and is often highly variable from examination to examination. But this, and other studies should heighten awareness concerning the significant prognostic implications of high-grade hematuria on the progression of IgAN.