Importance of citrate and the calcium : citrate ratio in patients with calcium renal lithiasis and severe lithogenesis
Miguel Angel Arrabal-Polo*, Miguel Arrabal-Martin*, Salvador Arias-Santiago**†, Juan Garrido-Gomez‡, Antonio PoyatosAndujar§ and Armando Zuluaga-Gomez**
Department of Urology, San Cecilio University Hospital, **Department of Medicine, Baza Hospital, †Department of Medicine, University of Granada, and ‡Departments of Traumatology and §Biochemistry, San Cecilio University Hospital, Granada, Spain
• 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.
MATERIAL AND METHODS
• 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.