Bone remodeling markers as lithogenic risk factors in patients with osteopenia-osteoporosis

To analyze the presence of phosphocalcic metabolism disorders in patients with osteopenia-osteoporosis without nephrolithiasis with respect to a control group.

A cross-sectional study was conducted in patients with osteopenia-osteoporosis without nephrolithiasis (n = 67) in lumbar spine or femur and in a control group (n = 61) with no lithiasis or bone disorders. Blood bone markers, phosphocalcic metabolism, fasting urine, 24-h urine lithogenic risk factors, and densitometry were recorded in both groups. SPSS 20.0 was used for statistical analysis.

In comparison with the controls, significantly higher blood calcium (9.27 ± 0.36 vs. 9.57 ± 0.38, p = 0.0001), intact parathormone (45.6 ± 14.9 vs. 53.8 ± 18.9, p = 0.008), and alkaline phosphatase (61.9 ± 20.9 vs. 70.74 ± 18.9, p = 0.014) levels were found in patients with osteopenia-osteoporosis. In the 24-h urine test, citrate (1010.7 ± 647.8 vs. 617.6 ± 315.8, p = 0.0001) and oxalate (28.21 ± 17.65 vs. 22.11 ± 16.49, p = 0.045) levels were significantly lower in osteopenia-osteoporosis patients than in controls, with no significant difference in calcium (187.3 ± 106.9 vs. 207.06 ± 98.12, p = 0.27) or uric acid (540.7 ± 186.2 vs. 511.9 ± 167.06, p = 0.35) levels. Patients with osteopenia-osteoporosis had significantly higher levels of lithogenic risk factors associated with bone remodeling, including significantly increased β-crosslaps and osteocalcin values and higher β-crosslaps/osteocalcin ratios.

Patients with osteopenia-osteoporosis without nephrolithiasis showed phosphocalcic metabolism disorders as well as lower urinary citrate and higher β-crosslaps/osteocalcin and fasting calcium/creatinine ratios, which would increase the risk of nephrolithiasis. Hence, prospective studies are warranted to evaluate the long-term risks.