Department of Urology, San Cecilio University Hospital, Spain.
BJU Int. 2013 Apr;111(4):622-7. doi: 10.1111/j.1464-410X.2012.11292.x. Epub 2012 Jul 3.
Different studies have shown the importance of citrate in the formation of calcium stones. It has further been shown that the states of metabolic acidosis result in an increase in bone resorption and lower urinary citrate levels. Increasing the intake of citrate in these patients can reduce the lithogenic risk and improve bone mineral density (BMD), contributing to control of both diseases. The study shows the importance of citrate in patients with calcium stones and BMD loss. The deficit in citrate excretion is associated with a decrease in bone mineralization and increased β-crosslaps. A calcium : citrate ratio >0.25 in patients with calcium stones and loss of mineral density may predict severe lithogenic activity.
To analyse the importance of urinary citrate and the urinary calcium : citrate ratio in patients with calcium renal lithiasis and severe lithogenesis compared with a control group of patients without lithiasis.
A cross-sectional study of 115 patients in eastern Andalusia, Spain was conducted. The patients were divided into two groups: Group A: 56 patients aged 25-60 years without calcium renal lithiasis; Group B: 59 patients aged 25-60 years, presenting with calcium renal lithiasis and severe lithogenesis. The citrate levels and the calcium : citrate ratio in the patients' urine and the relationship of these two factors to lithiasic activity were analysed and compared.
In Group B, 32.2% of the patients presented with hypocitraturia, compared with 14.3% of the patients in Group A (P = 0.02). The urinary citrate levels were lower in Group B than in Group A (P = 0.001) and the calcium : citrate ratio was higher in Group B than in Group A (P = 0.005). The results suggest that a patient urinary calcium : citrate ratio > 0.25 indicates severe lithogenesis (with a sensitivity of 89% and a specificity of 57%). After linear regression analysis, we found that the urinary citrate level is an independent factor associated with the changes in bone densitometry T-score values of patients.
The patients with severe lithogenesis presented with hypocitraturia, which was associated with lower bone mineral density. The calcium : citrate ratio, which is linearly related to the bone resorption marker β-crosslaps, could be useful in evaluating the risk of severe lithogenesis when this ratio is >0.25.
分析尿枸橼酸和尿钙/枸橼酸比值在伴有和不伴有肾结石的钙肾石症患者中的重要性。
对西班牙东部安达卢西亚的 115 例患者进行了横断面研究。将患者分为两组：A 组：56 例年龄 25-60 岁、无钙肾石症；B 组：59 例年龄 25-60 岁、有钙肾石症且结石形成严重。分析和比较了患者尿液中的枸橼酸盐水平和钙/枸橼酸比值及其与结石活性的关系。
在 B 组中，32.2%的患者存在枸橼酸排泄减少，而 A 组中这一比例为 14.3%（P=0.02）。B 组患者的尿枸橼酸水平低于 A 组（P=0.001），钙/枸橼酸比值高于 A 组（P=0.005）。结果表明，患者尿钙/枸橼酸比值>0.25 提示严重结石形成（敏感性 89%，特异性 57%）。经线性回归分析，我们发现尿枸橼酸水平是与患者骨密度计 T 评分值变化相关的独立因素。
严重结石形成患者存在枸橼酸排泄减少，与骨密度降低有关。钙/枸橼酸比值与骨吸收标志物β-交联肽呈线性相关，当比值>0.25 时，可用于评估严重结石形成的风险。
