Baseline hematuria in autosomal dominant polycystic kidney disease.

BACKGROUND: Hematuria is common in autosomal dominant polycystic kidney disease (ADPKD), but whether baseline hematuria predicts long-term kidney outcomes is unknown. We tested its association with kidney function decline, renal survival, and volume growth. METHODS: In a single-center ADPKD cohort, 175 patients had standardized urinary sediment assessment in a baseline period (2006-11); 173 (99%) were linked to a registry (follow-up up to 20 years). Microscopic hematuria was >5 erythrocytes per high-power field; macroscopic was from clinical history. Outcomes were the estimated glomerular filtration rate (eGFR) slope, a composite of end-stage kidney disease or eGFR halving, and total kidney volume (TKV) growth, adjusted for baseline eGFR, age, and sex. RESULTS: Baseline hematuria was present in 45 patients (26%; microscopic 15%, macroscopic 17%) and was associated with faster adjusted eGFR decline [mixed-model differential slope: any -1.46 ml/min/1.73 m²/year (95% confidence interval {CI}, -2.12 to -0.80); macroscopic -1.73 (-2.53 to -0.93); microscopic -1.53 (-2.34 to -0.73); P < .001 for all]. The composite end point was more frequent with hematuria (15-year event-free survival 33% vs. 58%; P = .002); macroscopic hematuria was independently associated [adjusted hazard ratio 1.97 (1.08-3.58); P = .03]. Hematuria was not associated with TKV growth (all P > .3). Associations persisted after adjustment for baseline kidney volume and albuminuria and in never-treated patients, were dose-dependent for macroscopic hematuria, and strengthened for microscopic hematuria when infection-associated episodes were excluded. CONCLUSIONS: Baseline hematuria-particularly macroscopic and non-infection-associated microscopic-independently predicts accelerated functional decline and worse renal survival. Because this prognostic signal is functional rather than volume-driven, this simple, routinely available finding may complement imaging-based risk markers.