Determinants of osteopenia in male renal-stone-disease patients with idiopathic hypercalciuria

Between a Rock and a Short Place-The Impact of Nephrolithiasis on Skeletal Growth and Development Across the Lifespan

PURPOSE OF REVIEW

The impact of nephrolithiasis on skeletal growth and bone health across the life span of kidney stone formers is reviewed.

MAIN FINDINGS

Bone disease is an early event among kidney stone formers (SF), with distinct phenotypes according to each age, sex, menopausal status, dietary, hormonal and genetic factors. Nephrolithiasis-associated bone disorder is characterized by reduced bone mineral density (BMD) and histologically discloses low bone formation, high bone resorption and abnormal mineralization. Although hypercalciuria has been presumed to be pathogenic for bone loss in SF, the association of BMD with urinary calcium is not uniform in all studies. Hypocitraturia, metabolic disturbances, cytokines and receptors, growth factors and acid-base status may all influence skeletal outcomes. The potential link of bone disease with vascular calcification and cardiovascular disease among SF is discussed. The unique vulnerability of the younger skeleton to the effects of nephrolithiasis on attainment of peak bone mass and strength is highlighted and the association of bone loss with kidney stone formation early in life indicate the opportunity for intervention to reduce the risk of future bone fractures.

2022 Recommendations of the AFU Lithiasis Committee: Medical management - from diagnosis to treatment

The morphological-compositional analysis of urinary stones allows distinguishing schematically several situations: dietary, digestive, metabolic/hormonal, infectious and genetic problems. Blood and urine testing are recommended in the first instance to identify risk factors of urinary stone disease in order to avoid recurrence or progression. The other objective is to detect a potential underlying pathology associated with high risk of urinary stone disease (e.g. primary hyperparathyroidism, primary or enteric hyperoxaluria, cystinuria, distal renal tubular acidosis) that may require specific management. Lifestyle-diet measures are the basis of the management of all stone types, but pharmacological treatments may be required. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU 2022] and their adaptability to the French context.

Risk factors for the comorbidity of osteoporosis/osteopenia and kidney stones: a cross-sectional study

Low femoral neck bone mineral density (BMD) was associated with the increased risk of kidney stones. Low dietary magnesium intake and increased serum alkaline phosphatase were associated with the increased risk of low femoral neck BMD in kidney stone formers.

PURPOSE

To evaluate whether low femoral neck bone mineral density (BMD) was associated with a higher risk of kidney stones, and identify risk factors for the comorbidity of osteoporosis/osteopenia and kidney stones.

METHODS

We analyzed individuals aged ≥ 20 years from National Health and Nutrition Examination Survey 2007-2020 data. Osteoporosis/osteopenia is defined as any T-score < -1.0 of femoral neck, total femoral, and mean lumbar spine (L1-L4) BMD. Dietary intakes (sodium, potassium, magnesium, calcium, phosphorus, calcium/phosphorus, vitamin D (25OHD2+25OHD3)) and serum parameters (sodium, potassium, calcium, phosphorus, bicarbonate, vitamin D, alkaline phosphatase (ALP)) were screened for identifying risk factors for the comorbidity.

RESULTS

The prevalence of comorbidity of osteoporosis/osteopenia and kidney stones was 4.82%. Femoral neck BMD T-score was negatively associated with the prevalence of kidney stones (n=11,864). Dietary magnesium intake, serum phosphorus, and bicarbonate were negatively associated with the comorbidity prevalence, and serum ALP was positively associated with the comorbidity prevalence (n=6978). Additionally, there remain significant associations of dietary magnesium intake, serum ALP, and bicarbonate with not only femoral neck BMD T-score (n=11331), but also the prevalence of kidney stones (n=23,111) in general population. Furthermore, dietary magnesium intake was positively correlated to femoral neck BMD T-score in stone formers (SFs), while serum ALP was negatively correlated to femoral neck BMD T-score in SFs (n=1163).

CONCLUSION

Low femoral neck BMD was closely associated with an increased risk of kidney stones. Low magnesium intake and increased serum ALP were associated with the increased risk of the comorbidity, as well as indicative of low femoral neck BMD T-score in SFs, which offered a clue to further clarify the mechanism leading to paradoxical calcification of bone resorption and kidney stones, and had the potential to perform personalized diagnostic workup for low BMD in SFs.

Prevalence of osteoporosis in patients with nephrolithiasis and vice versa: a cumulative analysis

Purpose

Nephrolithiasis is thought to be a risk factor for osteoporosis, but data assessing if osteoporosis predisposes to the risk of nephrolithiasis are lacking. The present study aims to investigate whether patients with nephrolithiasis have a prominently higher prevalence of osteoporosis than the controls and vice versa via a cumulative analysis.

Methods

Four databases were used to detect the eligible studies. We calculated the relative risk (RR) with a 95% confidence interval (CI) to assess the combined effect. The methodologies for conducting this study followed the PRISMA guidelines and were registered in the PROSPERO (ID: CRD42023395875).

Results

Nine case-control or cohort studies with a total of 454,464 participants were finally included. Combined results indicated that there was a significantly higher prevalence of osteoporosis in patients with nephrolithiasis as compared to the general population without nephrolithiasis (overall RR from six studies= 1.204, 95%CI: 1.133 to 1.28, P< 0.001; heterogeneity: I2 = 34.8%, P= 0.162). Conversely, osteoporosis was significantly correlated to an increased risk of nephrolithiasis as compared to the controls without osteoporosis (overall RR from four studies= 1.505, 95%CI: 1.309 to 1.731, P< 0.001; I2 = 89.8%, P< 0.001). Sensitivity analysis on the two categories validated the above findings. No significant publication bias was identified in this study.

Conclusions

The present study highlighted a significantly high prevalence of osteoporosis in patients with nephrolithiasis and vice versa. This reciprocal association reminded the clinicians to conduct a regular follow-up assessment when managing patients with nephrolithiasis or osteoporosis, especially for the elderly.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#searchadvanced, identifier CRD42023395875.

Correlation Between Renal Calculus Disease and Iliac Bone Thickness on a Single Non-contrast CT Scan

Background Renal calculi remain a major economic and health burden worldwide and are considered a systemic disorder associated with multiple other diseases. Several studies have observed that patients with idiopathic calcium renal stones show a reduction in bone mass. This study aimed to evaluate bone mass reduction on a non-contrast CT scan study in a group of idiopathic calcium-containing renal calculus disease patients in comparison with subjects without renal calculus disease. Methodology This non-interventional, cross-sectional study included a total of 300 patients with 150 cases (with renal calculi) and 150 controls (without renal calculi). Patients were divided according to age groups of 18-40, 40-60, and more than 60 years. The renal calculus size and the mean iliac bone thickness were calculated, and Spearman's correlation test was used to determine the correlation between them. Results The mean iliac bone thickness was significantly lower in the cases (3.29 mm) compared to the controls (9.73 mm with a standard deviation of 1.341 mm). There was a statistically significant negative correlation between the size of the renal calculus and the mean iliac bone thickness. Conclusions Renal calculus disease associated with hypercalciuria caused by increased bone resorption is reflected by the decreased iliac bone thickness on CT scans. Our study used the iliac bone (cancellous bone) in predicting bone mass reduction which shows changes early in the course of the disease compared to the neck of the femur and lumbar vertebrae (compact bones). It helps in predicting osteoporosis early and prevents the progression of the disease through early and appropriate clinical and urological intervention.

Vitamin D and Calcium Supplementation and Urolithiasis: A Controversial and Multifaceted Relationship

Patients with urolithiasis, and particularly those with hypercalciuria, frequently have a marked reduction of bone mineral content up to the levels of osteoporosis, with a significant increase in bone fracture risk. For these reasons, the indication to prescribe vitamin D and/or calcium supplementations is very frequent in such patients. On the other hand, both calcium supplementation, and even more vitamin D therapy, can worsen the risk of developing urolithiasis by increasing calcium, phosphate, and oxalate urinary excretion. Despite the clinical and practical relevance of this issue, the evidence on this topic is scarce and contradictory. Therefore, some concerns exist about how and whether to prescribe such supplements to a patient with a history of kidney stones. In this narrative review, we resume some pivotal pathophysiological concepts strictly related to the dealt topic, and we draw some considerations and personal opinions on the pros and cons of such prescriptions. Finally, we share with the reader our pragmatic algorithm for handling the urolithiasis risk in patients who have strong indications to be prescribed vitamin D and calcium supplementations.

Pediatric Nephrolithiasis

The prevalence of pediatric nephrolithiasis has increased dramatically in the past two decades for reasons that have yet to be fully elucidated. Workup of pediatric kidney stones should include metabolic assessment to identify and address any risk factors predisposing patients to recurrent stone formation, and treatment should aim to facilitate stone clearance while minimizing complications, radiation and anesthetic exposure, and other risks. Treatment methods include observation and supportive therapy, medical expulsive therapy, and surgical intervention, with choice of treatment method determined by clinicians' assessments of stone size, location, anatomic factors, comorbidities, other risk factors, and preferences and goals of patients and their families. Much of the current research into nephrolithiasis is restricted to adult populations, and more data are needed to better understand many aspects of the epidemiology and treatment of pediatric kidney stones.

The Reciprocal Relationship between Osteoporosis and Renal Stones

Previous studies have proposed an association between osteoporosis and renal stones. The current analyses intended to investigate the bidirectional relationship between osteoporosis and renal stones. The ≥40-year-old population in the National Health Insurance Service-Health Screening cohort (2002-2015) was analyzed. In study I, 67,811 patients with osteoporosis and 67,811 control I participants were matched. The hazard ratio (HR) of osteoporosis for renal stones was calculated using stratified Cox proportional hazard models. In study II, 25,261 patients with renal stones and 101,044 control II participants were matched. The HR of renal stones for osteoporosis was estimated using stratified Cox proportional hazard models. In study I, 3.4% (2276/67,811) of osteoporosis patients and 2.5% (1696/67,811) of control I participants had renal stones. Osteoporosis patients had a 1.36 times higher HR for renal stones than control I participants (95% confidence intervals [CI] = 1.28-1.45). In study II, 9.2% (2319/25,261) of renal stone patients and 7.6% (7658/101,044) of control II participants had osteoporosis. Renal stone patients had a 1.26 times higher HR for osteoporosis than control II participants (95% CI = 1.21-1.32). Adults with osteoporosis had a higher risk of renal stones. Moreover, adults with renal stones had a higher risk of osteoporosis.

How useful is an oral calcium load test for diagnosing recurrent calcium stone formers?

Hypercalciuria is the main risk factor for recurrent calcium urolithiasis. The goal of our study is to determinate how useful an oral calcium load test is for stone formers to classify different forms of hypercalciuria in pathogenetic categories defined as renal or absorptive according to the current knowledge. Between June 2013 and February 2016, a prospective study was carried out on 117 documented recurrent hypercalciuric stone formers undergoing an oral calcium load test modified from the original description by Pak. After 2 days of calcium-restricted diet, urine and blood were analyzed at baseline and 120 min after receiving orally 1 g of calcium. Total and ionized calcium, parathyroid hormone from serum and urine calcium and creatinine were assessed in order to divide patients in three groups as previously described: resorptive, absorptive, and renal hypercalciuria. This allowed the identification of 19, 39, 34 and 33 patients with normocalcemic primary hyperparathyroidism (NPHPT), renal hypercalciuria aka renal calcium leak (RCL), absorptive hypercalciuria (AH) and unidentified cause, respectively. Patients with NPHPT (who required parathyroidectomy) experienced a lower PTH decrease (41.41 ± 12.82 vs. 54.06 ± 13.84% p < 0.01), higher beta-crosslaps, as well as lower TmP/GFR and distal third radius bone mineral density. RCL resulted in increased fasting urine calcium-to-creatinine ratio (Uca/Cr), i.e., > 0.37 mmol/mmol), without hyperparathyroidism. AH was diagnosed by the presence of ΔUCa/Cr > 0.60 mmol/mmol between baseline and 120 min without any other anomaly. For all remaining patients, results were inconclusive due to the lack of sufficient increase in serum calcium or because the cause of lithogenesis could not be clearly identified. The oral calcium load test is useful in nearly 80% of patients by identifying the different forms of hypercalciuria causing urolithiasis and by guiding treatment, including parathyroid surgery.

Predictors of Bone Mineral Density in Kidney Stone Formers

Introduction

Nephrolithiasis is associated with an increased fracture risk, but predictors of bone mineral density (BMD) in stone formers (SFs) remain poorly defined.

Methods

We conducted a retrospective analysis in the Bern Kidney Stone Registry (BKSR), an observational cohort of kidney SFs. Inclusion criteria were age ≥18 years and ≥1 past stone episode. Participants with non–calcium (Ca)-containing kidney stones, a history of primary hyperparathyroidism or antiresorptive or anabolic bone treatment were excluded. Multivariable linear regression analyses were used to assess the association of blood and 24-hours urine parameters and stone composition with BMD at the lumbar spine and femoral neck.

Results

In the analysis, 504 participants were included, mean age was 46 years, and 76% were male. In multivariable analyses, fasting (β: −0.031; P = 0.042), postload (β: −0.059; P = 0.0028) and Δ postload − fasting (β: −0.053; P = 0.0029) urine Ca-to-creatinine ratios after 1 week of a sodium- and Ca- restricted diet and Ca oxalate dihydrate stone content (β: −0.042; P = 0.011) were negatively associated with z scores at the lumbar spine. At the femoral neck, alkaline phosphatase (β: −0.035; P = 0.0034) and parathyroid hormone (PTH) (β: −0.035; P = 0.0026) were negatively associated with z scores, whereas 24-hours urine Ca (β: 0.033; P = 0.0085), magnesium (β: 0.043; P = 3.5 × 10⁻⁴), and potassium (β: 0.032; P = 0.012) correlated positively with z scores at the femoral neck.

Conclusion

Our study reveals distinct predictors of BMD in SFs. Commonly available clinical parameters, such as kidney stone composition results, can be used to identify SFs at risk for low BMD.

Metabolic Evaluation: Place of the Calcium Load Test: How, When, For Whom, and Why?

Most human urinary stones are calcium-based and are often associated with hypercalciuria. A simple test described in 1975 by Pak et al allows for pathogenic classification of hypercalciuria: the calcium load test (CLT). The CLT explores calcium homeostasis after a low-calcium diet and then a calcium load (typically oral administration of 1 g of elemental calcium). Only simple laboratory equipment is required. Inadequate calcium excretion after a calcium-free diet or a calcium load is suggestive of resorptive or absorptive hypercalciuria, respectively. The CLT is particularly valuable in diagnosing primary hyperparathyroidism, even in most early stages of this disease. PATIENT SUMMARY: Kidney stone formation can be linked to calcium metabolism. When high calcium levels are found in urine despite adequate diet changes, a calcium load test may help to understand the underlying mechanisms. Urine and blood levels are explored during a low-calcium diet phase, and after a calcium load phase in the test. The calcium load test is particularly advantageous for revealing abnormally high function of the parathyroid gland, which is called hyperparathyroidism.

The effect of an oral sodium phosphate load on parathyroid hormone and fibroblast growth factor 23 secretion in normo- and hypercalciuric stone-forming patients

BACKGROUND & AIMS

Abnormalities of parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) secretion may cause calcium-phosphate (Ca-P) metabolism disorders in nephrolithiasis. Post-phosphate-load alterations in serum Ca, P and PTH, phosphaturia and calciuria enable monitoring hormonal regulation of Ca-P homeostasis. Our study aimed to determine differences in: 1.selected Ca-P metabolism parameters between healthy and kidney-stone-forming individuals, 2.PTH and FGF23 secretion induced by sodium-phosphate-load(NaP-load) in patients with/without hypercalciuria, 3.secretion of Ca-P related hormones in patients with low and normal/high serum concentrations of 25-hydroxyvitamin D₃ (25OHD₃).

METHODS

Sodium phosphates NaH₂PO₄/Na₂HPO₄-100mmol were administered orally for five days in 19 hypercalciuric [urinary Ca(U-Ca) 6.5 ± 1.7 mmol/d]-HSF, 35 normocalciuric (2.5±1 mmol/d)-NSF stone-forming patients and 19 controls (U-Ca 2.5 ± 1.4 mmol/d)-CG. On days 1 and 5 PTH-,FGF23-,Ca-,P were determined before and after NaP-load. The areas under PTH, FGF23 curves (AUC) were calculated. U-Ca, urinary phosphate (U-P) and sodium (U-Na) were also determined.

RESULTS

Following NaP-load, patients and controls exhibited expected alterations in Ca-P homeostasis. Despite changes in phosphate and PTH, no differences in FGF23 concentrations were observed. Patients differed from controls in having higher AUCPTH, calciuria and natriuresis, taking longer for PTH and P to normalize and lack of correlation between AUCPTH and phosphaturia. Post-NaP-load hypocalciuric effect of PTH secretion in NSF was less pronounced than in CG. In the HSFs, the hypocalciuric effect was more pronounced than in NSFs, but insufficient to correct hypercalciuria. In all stone-formers with low 25OHD₃ concentrations, the AUCFGF23 was significantly increased on first (1215 ± 605vs766 ± 315 p = 0.0457) and fifth days (1211 ± 641vs777 ± 299 p = 0.041) of NaP-load, compared to normal/high 25OHD₃-patients. Hypercalciuric patients with low 25OHD₃ concentrations had greater AUCPTH5 than those with normal/high 25OHD₃ (1005 ± 401vs835 ± 220 p = 0.0341).

CONCLUSIONS

Compared to controls, kidney-stone-forming patients exhibited enhanced PTH secretion after NaP-load. The HSFs showed a more pronounced hypocalciuric effect than NSFs, but insufficient to correct hypercalciuria. In hypercalciuric stone-formers with low 25OHD₃, FGF23 engagement in hyperphosphatemia reduction increased.

Metabolic effects of cholecalciferol supplementation in patients with calcium nephrolithiasis and vitamin D deficiency

INTRODUCTION

In this paper, we investigated whether cholecalciferol supplementation may increase the risk of stone recurrence in patients with calcium nephrolithiasis and Vitamin D deficiency.

METHODS

Thirty-three stone formers (56 ± 17 years old, 12 males) with 25(OH)D < 20 ng/mL were considered. Calcium excretion and urine supersaturation with calcium oxalate (ßCaOx) and brushite (ßbsh) were evaluated, both before and after cholecalciferol supplementation. Values of ß > 1 mean supersaturation. Cholecalciferol was prescribed as oral bolus of 100,000-200,000 IU, followed by weekly (5000-10,000 IU) or monthly (25,000-50,000 IU) doses. Calcium intake varied between 800 and 1000 mg/day. In urine, total nitrogen (TNE) was taken as an index of protein intake, sodium as a marker of dietary intake, and net acid excretion (NAE) as an index of acid-base balance.

RESULTS

TNE, sodium, and NAE did not change during the study (p = ns). Compared to baseline values, after cholecalciferol, both serum calcium and phosphate did not vary (p = ns); 25(OH)D increased from 11.8 ± 5.5 to 40.2 ± 12.2 ng/mL (p < 0.01); 1.25(OH)₂D increased from 41.6 ± 17.6 to 54 ± 16 pg/mL (p < 0.01); PTH decreased from 75 ± 27.2 to 56.7 ± 21.1 pg/mL (p < 0.01); urinary calcium increased from 2.7 ± 1.5 to 3.6 ± 1.6 mg/Kg b.w. (p < 0.01); ßbsh increased from 0.9 ± 0.7 to 1.3 ± 1.3 (p = 0.02); whereas ßCaOx varied but not significantly. Before cholecalciferol supplementation, 6/33 patients were hypercalciuric (i.e., urine Ca ≥ 4 mg/Kg b.w.) and increased to 13/33 after cholecalciferol supplementation (pX² = 0.03).

CONCLUSIONS

Cholecalciferol supplementation may increase calcium excretion, or reveal an underlying condition of absorptive hypercalciuria. This may increase both urine supersaturation with calcium salts and stone-forming risk.

Prevalence of idiopathic hypercalciuria in children with urinary system related symptoms attending a pediatric hospital in Bandar Abbas in 2014

Background

Idiopathic hypercalciuria is a group of diseases which can be manifested with urinary symptoms. Its importance is due to high prevalence, recurrent infections, and stone formations which are often asymptomatic.

Objective

The objective of this study was to determine the prevalence of idiopathic hypercalciuria in children with urinary system related symptoms in Bandar Abbas in 2014.

Methods

This descriptive cross-sectional study was done in 2014 in a children’s hospital in Bandar Abbas (southern Iran) on 321 children who were between 2 months to 14 years old. Random morning urine sample was obtained from all the patients, and calcium to creatinine ratio was assessed for all the patients for two times. Hypercalciuria is defined as urinary calcium excretion rate that is greater than 4 mg/kg per 24 hours in a child older than two years of age. Data was analyzed using IBM SPSS statistics 23.0 software and Chi-square and independent-samples t-test.

Results

Among the 321 children assessed, 153 (47.7%) had idiopathic hypercalciuria. The mean age of the children with idiopathic hypercalciuria was 55.20±43.71. Prevalence of idiopathic hypercalciuria was 48.3% in children with urinary tract infection, 54.9% and 53.6% in children with microscopic and macroscopic hematuria respectively, In children with dysuria, there were 52.1%, and 51.8% in children with frequency, 49.1% in children with kidney stone which was confirmed with sonography, 28.6% and 37.5% in children with nocturnal and daily urinary incontinency respectively. Results of this study showed no significant relationship between urinary system symptoms and idiopathic hypercalciuria (p>0.05).

Conclusion

Hypercalciuria can be presented with different symptoms associated with urinary symptoms. Therefore, it is recommended to check the urinary calcium level in children with urinary symptoms with no definite etiology.

The variation in urinary calcium levels in adult patients with fracture and surgical intervention

Background

Generally, a higher calcium diet is fed to fracture patients after surgery. However, recent studies have indicated that higher dietary calcium intakes increase the risk of urinary stones for fracture patients. Therefore, this study aimed to observe the variation in urinary calcium levels among fracture patients who underwent surgery, based on fracture type, fracture location, age and gender.

Methods

A total of 768 subjects were enrolled in this study from 2012 to 2015 and were divided into 2 groups: group A (fracture patients who underwent surgery) and group B (normal patients without fracture). Urine samples were collected for a 24-h period (24-h urine), at multiple specific time points before and after surgery for group A, or after hospitalisation for group B. Subsequently, urine calcium was detected and the changes were evaluated according to fracture location, fracture type, age and gender, as well as the distribution of hypercalciuria.

Results

Compared with group B, the level of urine calcium in group A significantly increased at different time points during the study period (P < 0.05). There were significant differences in the changes in urine calcium levels according to fracture location, fracture type and age, but not gender. Further, there were more patients with hypercalciuria in group A at the different time points, compared with group B.

Conclusion

Variation in urinary calcium among fracture patients that underwent surgery was of a regular pattern and hypercalciuria was also found in these patients. Therefore, a high-calcium diet and calcium supplements should be used with caution in this patient population.

Relationship between Urinary Calcium and Bone Mineral Density in Patients with Calcium Nephrolithiasis

PURPOSE

Calcium nephrolithiasis is associated with an increased risk of osteoporosis and fracture. Hypercalciuria has been assumed to be pathogenic for bone loss in kidney stone formers, although this association was shown in small cross-sectional studies. We explored the association of urine calcium with bone mineral density in kidney stone formers.

MATERIALS AND METHODS

We retrospectively studied bone mineral density in kidney stone formers. Excluded were subjects with hypercalcemia, chronic bowel disease, primary hyperparathyroidism, distal renal tubular acidosis or endogenous creatinine clearance less than 40 ml per minute. We included 250 males and 182 females subdivided into 145 who were estrogen treated and postmenopausal, and 37 who were nonestrogen treated and postmenopausal. We assessed the association of lumbar spine and femoral neck bone mineral density with 24-hour urine calcium on random and restricted diets, and while fasting using univariable and multivariable models adjusting for body mass index, urine sodium and sulfate.

RESULTS

On multivariable analysis no significant association was found between urine calcium on a random or a restricted diet, or during fasting conditions and femoral neck or lumbar spine bone mineral density in men and estrogen treated women. In estrogen untreated women lumbar spine bone mineral density inversely correlated with urine calcium on the restricted diet (r = -0.38, p = 0.04 and adjusted r = -0.45, p = 0.02) and in the fasting state (r = -0.42, p = 0.05).

CONCLUSIONS

Unlike in previous small cross-sectional studies we found no significant relationship between urine calcium and bone mineral density in a large group of calcium kidney stone formers. However, a significant inverse relationship was found in estrogen untreated kidney stone formers only. This study suggests that mechanism(s) other than hypercalciuria explain the lower bone mineral density and the higher fracture risk in patients who are kidney stone formers. It also highlights the role of estrogen on bone integrity.

Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement

BACKGROUND

Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research.

DESIGN

A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved.

RESULTS

Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients.

CONCLUSIONS

This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified.

Nephrolithiasis, bone mineral density, osteoporosis, and fractures: a systematic review and comparative meta-analysis

Our meta-analysis demonstrates that people with nephrolithiasis have decreased bone mineral density, an increased odds of osteoporosis, and potentially an elevated risk of fractures.

INTRODUCTION

People with nephrolithiasis might be at risk of reduced bone mineral density (BMD) and fractures, but the data is equivocal. We conducted a meta-analysis to investigate if patients with nephrolithiasis have worse bone health outcomes (BMD), osteoporosis, and fractures versus healthy controls (HCs).

METHODS

Two investigators searched major databases for articles reporting BMD (expressed as g/cm² or a T- or Z-score), osteoporosis or fractures in a sample of people with nephrolithiasis, and HCs. Standardized mean differences (SMDs), 95 % confidence intervals (CIs) were calculated for BMD parameters; in addition odds (ORs) for case-control and adjusted hazard ratios (HRs) in longitudinal studies for categorical variables were calculated.

RESULTS

From 1816 initial hits, 28 studies were included. A meta-analysis of case-control studies including 1595 patients with nephrolithiasis (mean age 41.1 years) versus 3402 HCs (mean age 40.2 years) was conducted. Patients with nephrolithiasis showed significant lower T-scores values for the spine (seven studies; SMD = -0.69; 95 % CI = -0.86 to -0.52; I ² = 0 %), total hip (seven studies; SMD = -0.82; 95 % CI = -1.11 to -0.52; I ² = 72 %), and femoral neck (six studies; SMD = -0.67; 95 % CI = --1.00 to -0.34; I ² = 69 %). A meta-analysis of the case-controlled studies suggests that people with nephrolithiasis are at increased risk of fractures (OR = 1.15, 95 % CI = 1.12-1.17, p < 0.0001, studies = 4), while the risk of fractures in two longitudinal studies demonstrated trend level significance (HR = 1.31, 95 % CI = 0.95-1.62). People with nephrolithiasis were four times more likely to have osteoporosis than HCs (OR = 4.12, p < 0.0001).

CONCLUSIONS

Nephrolithiasis is associated with lower BMD, an increased risk of osteoporosis, and possibly, fractures. Future screening/preventative interventions targeting bone health might be indicated.

The importance of urinary calcium in postmenopausal women with osteoporotic fracture

INTRODUCTION

Calcium stones are associated with osteoporosis and manifested mainly by elevated fasting urinary calcium/creatinine ratio. The objective of this study is to demonstrate the presence of abnormal metabolism of calcium and calciuria in women with osteoporotic fracture with no previously known renal lithiasis compared to women without osteoporosis and without renal lithiasis.

METHODS

In total, 87 women were included in the study. They were divided into two groups: Group 1 with 55 postmenopausal women with osteoporotic fracture and without renal lithiasis; and Group 2 with 32 postmenopausal women without osteoporosis and without history of renal lithiasis. The following parameters of phospho-calcium metabolism were analyzed: calciuria 24-hour, oxaluria 24-hour, uricosuria 24-hour, and citraturia 24-hour. The presence of hypercalciuria, hyperoxaluria, hyperuricosuria, and hypocitraturia was compared between groups. Statistical significance was set at p ≤ 0.05.

RESULTS

The mean age was 70.1 ± 13.8 in Group 1 and 56.7 ± 6.4 in Group 2 (p = 0.0001). Women in Group 1 had higher levels of serum alkaline phosphatase (p < 0.05) and fasting urinary calcium/creatinine ratio (p < 0.05). The percentage of patients with hypercalciuria in Group 1 (40%) was higher compared to Group 2 (18.8%) and statistically significant (p = 0.04). There were no statistically significant differences in the percentage of hyperoxaluria, hyperuricosuria, and hypocitraturia between groups. This study has its limitations including its cross-sectional nature at a unique centre and its low number of patients.

CONCLUSION

The determination of urinary calcium and fasting calcium/creatinine ratio in postmenopausal women with osteoporotic fracture without renal lithiasis may facilitate individualization of medical therapy and decreasing lithogenic risk.

Calcium nephrolithiasis and bone demineralization: pathophysiology, diagnosis, and medical management

PURPOSE OF REVIEW

To establish the relationship between calcium nephrolithiasis, bone densitometry scoring, and bone mineral density (BMD) loss according to bone turnover markers (BTMs) and urinary metabolites.

RECENT FINDINGS

Patients with recurrent calcium nephrolithiasis and idiopathic fasting hypercalciuria (urinary calcium/creatinine ratio >0.11) are more likely to have BMD loss that may lead to osteopenia or osteoporosis. In these patients, BTMs may be used as a surrogate for both bone health and stone recurrence. Suspect higher lithogenic states when calcium stone formers have serum beta-crosslaps (resorptive marker) greater than 0.311 ng/ml, serum osteocalcin (formative marker) greater than 13.2 ng/ml, and beta-crosslaps/osteocalcin ratio greater than 0.024.

SUMMARY

Patients with recurrent calcium nephrolithiasis and fasting hypercalciuria have a higher incidence of osteopenia and osteoporosis, measured by the dual-energy X-ray absorptiometry. These patients present not only with hypercalciuria and increased BTMs (mainly resorptive), but also up to 30% have hypocitraturia and increased urinary calcium/citrate ratio (>0.25). On the basis of these results, a diagnostic algorithm was created, classifying hypercalciurics according to their fasting calcium/creatinine and calcium/citrate ratio. Medical therapy for these patients is aimed at improving the dietary habits (normocalcemic, low salt, low animal protein diet), prescribing combinations of potassium citrate, thiazides, and bisphosphonates, and correcting bone and urinary abnormalities that may lower future skeletal and kidney stone risk.

Calcium and phosphorus metabolism and lithogenic factors in patients with osteoporotic fracture

OBJECTIVES

To demonstrate the attendance of mineral metabolism disorders and lithogenic factors in patients' urine with osteoporotic fracture without previously known stones

MATERIAL AND METHODS

67 patients with osteoporotic fractures surgically treated in trauma service are included. The area of the fracture site, fracture mechanism and the presence of osteoporosis were the factors taken into account to diagnose osteoporotic fracture. Mineral metabolism, calciuria, oxaluria, uricosuria and citraturia in 24hours urine were analyzed. The presence of abnormal calcium and phosphorus metabolism was proved comparing hypercalciuria patients with normocalciuria ones.

RESULTS

12 men and 55 women with mean age 68.8±14.5 years old were included. Mean Body Mass Index (BMI) was 27.4±4.1kg/m2. 42% of patients showed hypercalciuria, 34% hyperoxaluria, 34% hypocitraturia and 7% hyperuricosuria. Statistically significant differences were observed only in fasting calcium/creatinine ratio (0.17 vs. 0.08; P<.0001) when comparing patients with hypercalciuria with those with normocalciuria.

CONCLUSIONS

Patients with osteoporotic fractures show different lithogenic factors in urine, mainly hypercalciuria, always in fasting conditions.

Retrospective review of serum and urinary lithogenic risk factors in patients with osteoporosis and osteopenia

OBJECTIVE

To analyze differences in bone remodeling markers, lithogenic factors and bone densitometry among the 3 groups of patients (controls, patients with relapsing calcium renal lithiasis, and patients with loss of bone mineral density without lithiasis).

MATERIAL AND METHODS

This is a cross-sectional study including 203 patients who were divided in 3 groups: group 1 (controls), group 2 (patients with relapsing calcium renal lithiasis), and group 3 (patients with osteopenia and/or osteoporosis in the lumbar spine or hip). Bone densitometry, calcium-phosphorous and bone metabolism analysis, and analysis of lithogenic risk factors in fasting urine samples and 24-hour urine samples were performed. Statistical analysis was performed with SPSS 17.0. A P ≤.05 was considered statistically significant.

RESULTS

Patients in group 2 presented greater calcium excretion and a lower citrate excretion in 24-hour urine samples as compared with the other 2 groups. The proportion of hypercalciuria and hypocitraturia was higher in group 2. In addition, patients in group 2 presented a lower loss of bone mineral density as well as altered bone remodeling markers as compared with those in group 1. Patients in group 3 also presented alterations in urine calcium and citrate excretion with respect to the control group, with elevated fasting calcium and citrate levels and calcium-to-citrateratio.

CONCLUSION

Lithogenic risk factors are altered in patients with osteopenia and/or osteoporosis without renal lithiasis although to a lesser extent than patients with calcium renal lithiasis.

Demographics and characterization of 10,282 Randall plaque-related kidney stones: a new epidemic?

Renal stone incidence has progressively increased in industrialized countries, but the implication of Randall plaque in this epidemic remains unknown. Our objectives were to determine whether the prevalence of Randall plaque-related stones increased during the past decades after having analyzed 30,149 intact stones containing mainly calcium oxalate since 1989 (cross-sectional study), and to identify determinants associated with Randall plaque-related stones in patients (case-control study). The proportion of Randall plaque-related stones was assessed over 3 time periods: 1989-1991, 1999-2001, and 2009-2011. Moreover, we analyzed clinical and biochemical parameters of 105 patients affected by calcium oxalate stones, with or without plaque. Of 30,149 calcium oxalate stones, 10,282 harbored Randall plaque residues (34.1%). The prevalence of Randall plaque-related stones increased dramatically during the past years. In young women, 17% of calcium oxalate stones were associated with Randall plaque during the 1989-1991 period, but the proportion rose to 59% 20 years later (P < 0.001). Patients with plaques experienced their first stone-related event earlier in life as compared with those without plaque (median age 26 vs 34 years, P = 0.02), had increased ionized serum calcium levels (P = 0.04), and increased serum osteocalcin (P = 0.001) but similar 25-hydroxyvitamin D levels. The logistic regression analysis showed that age (odds ratio [OR] 0.96, confidence interval [CI] 0.926-0.994, P = 0.02), weight (OR 0.97, CI 0.934-0.997, P = 0.03), and osteocalcin serum levels (OR 1.12, CI 1.020-1.234, P = 0.02) were independently associated with Randall plaque. The prevalence of the FokI f vitamin D receptor polymorphism was higher in patients with plaque (P = 0.047). In conclusion, these findings point to an epidemic of Randall plaque-associated renal stones in young patients, and suggest a possible implication of altered vitamin D response.

The importance of calciuria as lithogenic factors in patients with osteopenia/osteoporosis

PURPOSE

Recurrent kidney stones are associated with bone mineral density loss, altered bone remodeling markers, hypercalciuria and increased in fasting calcium/creatinine ratio. The objective was to determine biochemical alterations in urine in patients with osteopenia/osteoporosis without calcium kidney stones compared with patients with calcium kidney stones.

METHODS

This is a cross-sectional study including 142 patients who were divided in two groups: Group 1 (patients with recurrent calcium kidney stones) and Group 2 (patients with osteopenia/osteoporosis in the lumbar spine or hip). Analyses of bone mineral density, calcium-phosphorous and bone metabolism and lithogenic risk factors in fasting urine samples and 24-h urine samples were performed. Statistical analysis was carried out with SPSS 17.0. A p ≤ 0.05 was considered statistically significant.

RESULTS

Patients in Group 2 presented greater loss of bone mineral density and more elevated alkaline phosphatase, iPTH, phosphorous and β-crosslaps levels, as compared to patients in Group 1. However, Group 1 presented greater urine calcium, oxalate and uric acid and a higher proportion of hypocitraturia, hypercalciuria and hyperoxaluria, as compared to Group 2. Multivariate analysis revealed that advanced age and β-crosslaps levels are risk factors for bone mineral density loss, while low urinary calcium excretion was protective against bone demineralization.

CONCLUSION

Patients with osteopenia/osteoporosis without lithiasis present some urinary biochemical alterations. This would explain the lack of lithogenic activity, although low calcium excretion in 24-h urine samples is a protective factor against the loss of bone mineral density.

Vascular calcification and bone mineral density in recurrent kidney stone formers

BACKGROUND AND OBJECTIVES

Recent epidemiologic studies have provided evidence for an association between nephrolithiasis and cardiovascular disease, although the underlying mechanism is still unclear. Vascular calcification (VC) is a strong predictor of cardiovascular morbidity and the hypothesis explored in this study is that VC is more prevalent in calcium kidney stone formers (KSFs). The aims of this study were to determine (1) whether recurrent calcium KSFs have more VC and osteoporosis compared with controls and (2) whether hypercalciuria is related to VC in KSFs.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a retrospective, matched case-control study that included KSFs attending an outpatient nephrology clinic of the Royal Free Hospital (London, UK) from 2011 to 2014. Age- and sex-matched non-stone formers were drawn from a list of potential living kidney donors from the same hospital. A total of 111 patients were investigated, of which 57 were KSFs and 54 were healthy controls. Abdominal aortic calcification (AAC) and vertebral bone mineral density (BMD) were assessed using available computed tomography (CT) imaging. The prevalence, severity, and associations of AAC and CT BMD between KSFs and non-stone formers were compared.

RESULTS

Mean age was 47±14 years in KSFs and 47±13 in non-stone formers. Men represented 56% and 57% of KSFs and non-stone formers, respectively. The prevalence of AAC was similar in both groups (38% in KSFs versus 35% in controls, P=0.69). However, the AAC severity score (median [25th percentile, 75th percentile]) was significantly higher in KSFs compared with the control group (0 [0, 43] versus 0 [0, 10], P<0.001). In addition, the average CT BMD was significantly lower in KSFs (159±53 versus 194 ±48 Hounsfield units, P<0.001). A multivariate model adjusted for age, sex, high BP, diabetes, smoking status, and eGFR confirmed that KSFs have higher AAC scores and lower CT BMD compared with non-stone formers (P<0.001 for both). Among stone formers, the association between AAC score and hypercalciuria was not statistically significant (P=0.86).

CONCLUSIONS

This study demonstrates that patients with calcium kidney stones suffer from significantly higher degrees of aortic calcification than age- and sex-matched non-stone formers, suggesting that VC may be an underlying mechanism explaining reported associations between nephrolithiasis and cardiovascular disease. Moreover, bone demineralization is more prominent in KSFs. However, more data are needed to confirm the possibility of potentially common underlying mechanisms leading to extraosseous calcium deposition and osteoporosis in KSFs.

Osteoporosis and the risk of symptomatic nephrolithiasis: a population-based 5-year follow-up study in Taiwan

This study estimates the risk of symptomatic nephrolithiasis within 5 years of newly diagnosed osteoporosis in a Taiwan population. This cohort study consisted of patients with a diagnosis of osteoporosis between Jan. 2003 and Dec. 2005 (N = 1634). Four age- and gender- matched patients for every patient in the study cohort were selected using random sampling as the comparison cohort (N = 6536). All patients were tracked for 5 years from the date of cohort entry to identify whether they developed symptomatic nephrolithiasis. Cox proportional hazard regressions were performed to evaluate the 5-year nephrolithiasis-free survival rates. During the 5-year follow-up period, 60 osteoporosis patients (3.7%) and 165 non- osteoporosis patients (2.5%) developed symptomatic nephrolithiasis. The adjusted HR of symptomatic nephrolithiasis was 1.38 times greater risk for patients with osteoporosis than for the comparison cohort (95% confidence interval (CI) 1.03-1.86; P < .05). Osteoporosis is very likely to be an independent risk factor for subsequent diagnosis of symptomatic nephrolithiasis.

The relation between bone and stone formation

Hypercalciuria is the most common metabolic abnormality found in patients with calcium-containing kidney stones. Patients with hypercalciuria often excrete more calcium than they absorb, indicating a net loss of total-body calcium. The source of this additional urinary calcium is almost certainly the skeleton, the largest repository of calcium in the body. Hypercalciuric stone formers exhibit decreased bone mineral density (BMD), which is correlated with the increase in urine calcium excretion. The decreased BMD also correlates with an increase in markers of bone turnover as well as increased fractures. In humans, it is difficult to determine the cause of the decreased BMD in hypercalciuric stone formers. To study the effect of hypercalciuria on bone, we utilized our genetic hypercalciuric stone-forming (GHS) rats, which were developed through successive inbreeding of the most hypercalciuric Sprague-Dawley rats. GHS rats excrete significantly more urinary calcium than similarly fed controls, and all the GHS rats form kidney stones while control rats do not. The hypercalciuria is due to a systemic dysregulation of calcium homeostasis, with increased intestinal calcium absorption, enhanced bone mineral resorption, and decreased renal tubule calcium reabsorption associated with an increase in vitamin D receptors in all these target tissues. We recently found that GHS rats fed an ample calcium diet have reduced BMD and that their bones are more fracture-prone, indicating an intrinsic disorder of bone not secondary to diet. Using this model, we should better understand the pathogenesis of hypercalciuria and stone formation in humans to ultimately improve the bone health of patients with kidney stones.

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.

Association of severe calcium lithogenic activity and bone remodeling markers

OBJECTIVE

To establish cutoff points for markers of bone remodeling that allow for screening of patients at risk for serious lithogenic activity.

MATERIALS AND METHODS

We conducted a cross-sectional study with 182 patients (aged between 25 and 60 years) divided into 3 groups: group 1, 56 patients without lithiasis; group 2, 67 patients with light calcium lithiasis; and group 3, 59 patients with severe calcium lithiasis. The criteria for inclusion in and exclusion from the study were established, and light and severe lithogenic activity were defined. Metabolic variables in blood and urine, along with bone densitometry, were studied for the groups. Statistical analysis of the results and preparation of receiver operating characteristic curves to establish optimal cutoff points were performed.

RESULTS

The patients in group 3 showed the greatest bone mineral density loss and the highest values for markers of bone remodeling, together with increased 24-hour calciuria. Using the receiver operating characteristic curves developed and based on statistical significance (P = .0001), the following cutoff points for severe lithogenic activity, with a sensitivity between 75% and 85%, were established: β-crosslaps >0.331 ng/mL; osteocalcin >13.2 ng/mL; β-crosslaps/osteocalcin >0.024; 24-hour calciuria >306.6 mg; and fasting urine calcium/creatinine >0.105.

CONCLUSION

Patients with calcium lithiasis and elevated values for osteocalcin, β-crosslaps, β-crosslaps/osteocalcin, 24-hour calciuria, and fasting urine calcium/creatinine may present a high risk of severe lithogenic activity.

Idiopathic hypercalciuria and bone health

Calcium is an important participant in many physiologic processes including coagulation, cell membrane transfer, hormone release, neuromuscular activation, and myocardial contraction. The body cooperates in a sophisticated web of hormonally mediated interactions to maintain stable extracellular calcium levels. Calcium is vital for skeletal mineralization, and perturbations in extracellular calcium may be corrected at the expense of bone strength and integrity. The aim of this review is to delineate our current understanding of idiopathic hypercalciuria in the context of bone health, specifically its definition, etiology, epidemiology, laboratory evaluation, and potential therapeutic management.

Association of bone mineral density with incidental renal stone in long-term survivors of childhood acute lymphoblastic leukemia

PURPOSE

Our objective was to evaluate the association between low bone mineral density (BMD) and incidental renal stones among long-term survivors of childhood acute lymphoblastic leukemia (ALL).

METHODS

Adult participants who were 10+ years from their childhood ALL diagnosis and members of the St. Jude Lifetime Cohort study were recruited between December 2007 and March 2011. During their risk-based medical evaluations, they underwent quantitative computed tomography (QCT) to evaluate BMD. Incidental renal stones were identified by radiologists' review of axial QCT source images. Demographic and dietary information were abstracted from health surveys and the Block Food Frequency questionnaire, respectively. The multivariable logistic regression model was used for analysis.

RESULTS

At a median of 26.1 years from diagnosis, BMD Z scores were ≤-2 in 34 of 662 (5.2 %) and renal stones detected in 73 of 662 (11 %) participants. Adjusted for age, renal radiation, dietary vitamin D, gender, and body mass index, when compared to those with BMD Z scores ≥0, the risk of renal stones was increased among those with BMD Z scores ≤-2 (odds ratio [OR], 2.92; 95 % confidence interval [CI] 1.14-7.48). Risk of renal stones significantly increased for older age (45-54 vs.18-24 years; OR, 3.70; 95 % CI 1.11-12.35) whereas the risk was higher but nonsignificant for >141.5 IU (sample median) daily intake of vitamin D (OR, 1.64; 95 % CI 0.98-2.75).

CONCLUSIONS AND IMPLICATIONS FOR CANCER SURVIVORS

Older ALL survivors with BMD Z scores ≤-2 are at risk for renal stones and should be counseled so that appropriate follow-up care can be provided for those among whom renal stones are detected.

Osteopenia/osteoporosis in patients with calcium nephrolithiasis

The objective of this study is to analyze the alterations in bone mineral density and bone and calcium-phosphorus metabolism in patients with calcium nephrolithiasis. We designed a study with 182 patients who were distributed among three groups: group O, 56 patients without nephrolithiasis; group A, 67 patients with calcium nephrolithiasis and mild lithogenic activity; and group B, 59 patients with calcium nephrolithiasis and severe lithogenic activity. Metabolic parameters of blood and urine that were related to calcium-phosphorous and bone metabolism and bone densitometry were assessed in all patients. A comparative study was performed on the variables of bone and calcium-phosphorus metabolism and bone densitometry as well as the presence or absence of osteopenia/osteoporosis. The patients in group B had a greater loss of bone mineral density, measured by the T-score, than the patients in groups O and A. Moreover, the proportion of patients in group B with osteopenia/osteoporosis was statistically significantly higher than the proportion of patients in groups O and A. We observed higher values of calciuria, fasting calcium/creatinine ratio, and 24-h calcium/creatinine among the patients in group B compared to the other two groups. Calciuria, citraturia, and fasting calcium/creatinine were independent factors that showed a relationship with severe lithogenic activity compared to the control group, and β-crosslaps is an independent factor that has a relationship with severe lithogenic activity as compared to mild lithogenic activity. Patients with calcium lithiasis and severe lithogenic activity have a greater loss in bone mineral density and therefore a greater risk of osteopenia/osteoporosis.