Calcium renal lithiasis and bone mineral density. Importance of bone metabolism in urinary lithiasis.

CONTEXT Calcium Nephrolithiasis is a multifactorial disease; in its pathophysiology is involved various minerals and metabolic factors that may be altered, including bone and phosphor-calcium metabolism. OBJECTIVE To establish the scientific evidence and demonstrate the relationship between calcium nephrolithiasis and bone mineral density loss, through the use of bone turnover markers, serum and urinary metabolites. EVIDENCE ACQUISITION We performed a PubMed literature review using different MeSH Terms like "Nephrolithiasis", "Bone mineral density", "Urinary stones", "Calcium", Bone resorption" and "Bone formation", with different combinations. We only selected articles with abstracts in English or Spanish and discarded clinical cases and articles with inappropriate statistical study. A total of 40 articles were selected. EVIDENCE SYNTHESIS In different studies reviewed have been observed that patients with hypercalciuria have a higher bone mineral density loss with respect to normocalciuric. Among patients with calcium stones (normocalciuric or hypercalciuric), there is loss of bone mineral density, being more evident in patients with stones and hypercalciuria. This mineral density loss is marked and important in patients with recurrent calcium stones. Increased markers like fasting calcium/creatinine and β-CrossLaps are determinant of nephrolithiasis and mineral density loss in these patients. CONCLUSION We recommend perform markers of bone turnover and fasting calcium/creatinine in patients with recurrent calcium stones by the significant presence of bone mineral density loss, with a level of evidence III.