Litiasis renal cálcica y la relación con la enfermedad mineral ósea

Abstract

Calcium renal lithiasis and metabolic bone disease (osteopenia / osteoporosis) are two very prevalent diseases in Primary Care, which represent a significant health expense and also generate great morbidity in patients. Calcium renal lithiasis has a multifactorial origin in which alterations in phospho-calcium metabolism, deficiency of crystallization inhibitors or anatomical factors, among others, have been implicated. Recent studies show that there is a relationship between renal calcium lithiasis and loss of bone mineral density, although the relationship between both pathologies has not been clearly established. Knowing the physiopathogenic mechanisms that relate both diseases will be very important to be able to establish a preventive treatment and make an early diagnosis in those cases in which it is possible, for this reason more studies are required that analyse the lithogenic factors in those patients with osteopenia-osteoporosis without lithiasis to determine the presence of early biochemical alterations in serum or urine and that may favour the future risk of lithiasis. The main objective of this doctoral thesis is to analyse the prevalence of lithogenic risk factors in serum and urine, phospho-calcium metabolism and bone remodelling markers in patients with osteopenia-osteoporosis. Secondarily, vitamin D deficiency was analysed in patients with kidney stones. Material and methods Patients diagnosed with calcium kidney stones, osteopenia and osteoporosis and control subjects without relevant pathology have been included. Patients with kidney stones belong to the Lithiasis and Endourology Unit of the San Cecilio University Hospital in Granada, which is a reference center. The patients with osteopeniaosteoporosis have been recruited in the Endocrinology Service and the control subjects belong to the Urology and Dermatology Departments of the Hospitals of Granada, who consulted for trivial pathology and without a history of renal lithiasis or ostepeniaosteoporosis or pathologies associated. In all included patients, the lithogenic risk parameters were studied in blood, fasting urine and 24-hour urine. In addition, markers of bone resorption, phosphocalcic metabolism and vitamin D have been studied, as well as clinical studies of hyperparathyroidism. Results Patients with osteopenia/osteoporosis have a higher prevalence of hypocitraturia and hypercalciuria in relation to control subjects, but lower than individuals with severe lithiasis. Patients with osteopenia-osteoporosis without lithiasis present a higher prevalence of bone remodeling factors associated with lithogenic activity such as β- crosslaps> 0.311 ng / ml (92.5 vs. 59%), osteocalcin> 13.2 ng / ml (71.6 vs. 44.3%), β- crosslaps / osteocalcin> 0.024 (77.6 vs. 52.5% for patients and controls respectively) and a significant increase in the calcium/ creatinine ratio both in fasting urine and in 24h urine. A significant linear correlation was also observed between β-crosslaps and 24-hour calciuria and the 24-hour calcium/ creatinine ratio. In addition, those patients who have a bone mineral density below -1 (T score <-1) and who have kidney stones have significantly higher calciuria values. The risk of hypovitaminosis D was twice higher in those patients with kidney stones in relation to the control group and with significant differences in the mean values of vitamin D in both groups. Furthermore, those patients with a history of lithiasis and vitamin D deficiency had significantly higher levels of iPTH. Conclusions Patients with osteopenia-osteoporosis without lithiasis present metabolic lithogenic risk factors such as hypercalciuria and hypocitraturia. Furthermore, bone resorption markers are significantly higher in patients with osteopenia-osteoporosis in relation to the control group. Patients with calcium kidney stones have a higher prevalence of vitamin D deficiency, which was related to higher levels of iPTH. Osteopenia, osteoporosis and calcium renal lithiasis present common metabolic alterations, which is why a holistic comprehensive management of both processes is necessary in Primary and Specialized Care.