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-centre ADPKD cohort, 175 patients had standardized urinary sediment assessment in a baseline period (2006–2011); 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 < 0.001 for all). The composite end point was more frequent with hematuria (15-year event-free survival 33% versus 58%; P = 0.002); macroscopic hematuria was independently associated (adjusted hazard ratio 1.97 [1.08–3.58]; P = 0.03). Hematuria was not associated with TKV growth (all P > 0.3). 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.