Endoscopically visible Randall's plaques are an independent predictor of future stone events.

Randall’s plaques have been long thought to be precursors for kidney stone formation, but how their presence impacts future stone recurrence is not known. The aim of this study was to determine whether patients with endoscopically visible plaques were more likely to have subsequent stone events compared to those without. The presence of Randall’s plaque in adult patients was prospectively assessed during endoscopic cases as part of the Registry for Stones of the Kidney and Ureter (ReSKU). In each case, the visible Randall’s plaque burden was scored by the attending surgeon as “none,” “minimal,” or “many.” Data regarding stone composition, 24-hour urine tests, and subsequent stone events on follow up were collected. Stone events were defined as patient-reported stone passage or any primary operation for kidney stones; second-look or staged operations were not counted as separate stone events. We identified 673 subjects with a Randall’s plaque assessment, of which 78 had “none,” 306 had “minimal,” and 289 had “many.” Despite having no significant differences in initial stone burden, subjects with visible Randall’s plaque (“minimal” or “many”) had a higher relative risk of stone recurrences after surgery compared to those without (RRR 1.711 (1.121–2.611), p = 0.01). Interestingly, no significant differences in 24-hour urine analytes were observed. Subjects with visible plaque were more likely to have calcium-based stones (84% vs. 58%, p < 0.001). The presence of endoscopically visible Randall’s plaque is associated with an increased risk of stone recurrence independent of urine composition.