Joel Iff, Ankit Shah, Rajeshwari Nair, Mirko Fillbrunn, Ogo Egbuna, Manish Maski, Rui Huang, Dumingu Aparna Gomes, Edward Tuttle, Whitney Longstaff, Janice Stricker-Shaver, Beth Barber
Forty-three studies were included in the systematic literature review, of which 15 study entries from 13 publications were included in meta-analyses. Across studies, persistent microhematuria was consistently associated with worse long-term kidney outcomes. In pooled analyses, microhematuria (both persistent and single-timepoint measurements) was associated with an increased risk of end-stage kidney disease or related outcomes (hazard ratio [HR] 2.33, 95% confidence interval [CI] 1.94-2.80), with a stronger and consistent association observed for persistent microhematuria (HR 2.57, 95% CI 1.94-3.41). Single-timepoint measurement of microhematuria showed a nonsignificant directional association with substantial variability across studies, whereas macrohematuria (predominantly measured at a single timepoint) was associated with improved kidney outcomes (HR 0.56, 95% CI 0.37-0.83).
INTRODUCTION: Hematuria is the most common clinical manifestation of Immunoglobulin A nephropathy (IgAN) and has been associated with adverse long-term kidney outcomes, although its prognostic significance has not been clearly established. This systematic literature review and meta-analysis aimed to evaluate whether hematuria is a prognostic marker of long-term kidney outcomes.
METHODS: A search of PubMed/MEDLINE and Embase (January 2005 to June 2025) identified studies assessing persistent or single-timepoint measurement of microhematuria or macrohematuria in relation to kidney outcomes. Studies meeting predefined criteria were qualitatively synthesized, and those with comparable outcome definitions were included in meta-analyses using random-effects models.
RESULTS: Forty-three studies were included in the systematic literature review, of which 15 study entries from 13 publications were included in meta-analyses. Across studies, persistent microhematuria was consistently associated with worse long-term kidney outcomes. In pooled analyses, microhematuria (both persistent and single-timepoint measurements) was associated with an increased risk of end-stage kidney disease or related outcomes (hazard ratio [HR] 2.33, 95% confidence interval [CI] 1.94-2.80), with a stronger and consistent association observed for persistent microhematuria (HR 2.57, 95% CI 1.94-3.41). Single-timepoint measurement of microhematuria showed a nonsignificant directional association with substantial variability across studies, whereas macrohematuria (predominantly measured at a single timepoint) was associated with improved kidney outcomes (HR 0.56, 95% CI 0.37-0.83).
DISCUSSION: These findings support persistent microhematuria as a strong and consistent predictor of kidney failure in IgAN, substantiating its role as a clinically relevant prognostic marker.