Relative Supersaturation of 24-Hour Urine and Likelihood of Kidney Stones

Abstract

Purpose Relative supersaturations of calcium oxalate, calcium phosphate, and uric acid are used clinically in kidney stone prevention. The magnitudes of association between relative supersaturation and stone risk require further quantification. Materials and Methods We performed a cross-sectional study using 24-hour urine collections from Nurses’ Health Study I (NHS I), Nurses’ Health Study II (NHS II), and Health Professional Follow-up Study (HPFS) cohorts to quantify the association between calcium oxalate, calcium phosphate, and uric acid relative supersaturations levels and likelihood of stone formation. Results: Odds ratio (OR) for being a stone former were 5.85 (3.40 to 10.04) in NHS I, 6.38 (3.72 to 11.0) in NHS II, and 6.95 (3.56 to 13.6) in HPFS for the highest category of calcium oxalate relative supersaturation compared with <1.0. The OR for being a stone former were 1.86 (0.94 to 3.71) in NHS I, 4.37 (2.68 to 7.10) in NHS II, and 3.59 (2.04 to 6.31) in HPFS for the highest category of calcium phosphate relative supersaturation compared with <1.0. For uric acid relative supersaturation, OR for being a stone former were 4.30 (2.34 to 7.90) in NHS I and 2.74 (1.71 to 4.40) in NHS II for the highest relative supersaturation category compared with <1.0. In HPFS, uric acid relative supersaturation was not significantly associated with likelihood of stone formation. Conclusion Likelihood of being a stone former increases with higher calcium oxalate and calcium phosphate relative supersaturation levels in men and women, and higher relative supersaturation levels of uric acid in women.

Risk Factors for Kidney Stone Formation following Bariatric Surgery

“…32 These findings are consistent with data in non-bariatric patients showing higher urine CaOx SS is associated with higher risk of being a kidney stone former. 45 For this reason, understanding post-surgical changes in urine CaOx SS and its major contributors can provide insight into why some individuals form kidney stones after surgery. The primary individual urine components that influence urine CaOx SS level include urine calcium, oxalate, citrate, and volume.…”

Contribution of Dietary Oxalate and Oxalate Precursors to Urinary Oxalate Excretion

“…Kidney stone disease affects approximately 10% of the population [ 1 ] and calcium oxalate (CaOx) is the most common stone composition [ 2 ]. Supersaturation of urine with CaOx markedly increases the risk of stone formation [ 3 ], and supersaturation is the driving force behind CaOx crystal precipitation [ 4 ]. The contribution of urinary oxalate to supersaturation of CaOx is significant.…”

Nephrolithiasis and Elevated Urinary Ammonium: A Matched Comparative Study

“…While several of these urinary analytes such as calcium, citrate, oxalate, pH, and calcium oxalate and calcium phosphate (CP) supersaturation are commonly used as indicators for medical or dietary intervention, 6,7 little is known about the clinical and prognostic significance of elevated urinary ammonium. Urine ammonium measurements reflect renal ammoniagenesis.…”