Lithogenic factors in postmenopausal women with osteoporotic fracture

The aim of this study was to show the presence of phosphorus and calcium metabolism disorders and the presence of urine lithogenic factors in women with osteoporotic fracture without previous urinary lithiasis.

We conducted a cross-sectional study including 55 women with osteoporotic fracture surgically treated in the Trauma Department. We included women with osteoporotic fracture demonstrated by the fracture area, fracture mechanism and the presence of osteoporosis by bone densitometry. We analyzed phospho-calcium metabolism as well as the calciuria, oxaluria, citraturia and uricosuria levels with fasting and 24-hour urine study. The presence of abnormal calcium and phosphorus metabolism was compared between women with hypercalciuria and normocalciuria.

The 55 women had a mean age of 70.1±13.8 years and a mean body mass index of 27.9±3.8 kg/m2. Forty-percent of the patients showed hypercalciuria, 36.4% hyperoxaluria, 36.4% hypocitraturia, and 5.3% hyperuricosuria. When comparing patients with hypercalciuria and normocalciuria, the only statistically significant difference was fasting urinary calcium/creatinine levels (0.16 versus 0.08, respectively; P<0.0001).

Women with osteoporotic fracture showed several lithogenic factors in the urine studies, mainly fasting hypercalciuria. Although in this study hypercalciuria did not involve the presence of lithiasis, it can favor the appearance of lithiasis with other predisposing conditions. Therefore, an accurate assessment of urine calcium levels with other lithogenic factors, such as citrate and oxalate levels, may facilitate individualized management and treatment of osteoporosis without increasing the risk of nephrolithiasis.