Association between osteoporosis and urinary calculus: evidence from a population-based study

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.

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.

Bisphosphonates and management of kidney stones and bone disease

PURPOSE OF REVIEW

Kidney stones are strongly associated with low bone density and bone fracture. Clinical management focuses on prevention of kidney stones and bone fracture. We reviewed literature of kidney stones and bone disease with a special focus on updates in therapeutic strategies. We will review the literature regarding dietary management, supplements, and medications and emphasize the recent studies on bisphosphonates and kidney stone management.

RECENT FINDINGS

Bisphosphonate medications are commonly used in management of low bone density. Previous studies showed that they reduce urinary calcium. A recent large prospective study found that bisphosphonates may reduce the risk of kidney stones in individuals who have low bone density. In addition to lowering urinary calcium, a recent study found that bisphosphonates may act as an inhibitor in the urinary space.

SUMMARY

There are multiple dietary and pharmacologic strategies that can be considered for kidney stones and bone disease, such as low salt and normal calcium diet, as well as thiazides, alkali, and bisphosphonate medications. Bisphosphonates may have an important role in reducing bone resorption and reducing overall risk of kidney stone and bone disease.

Oxalates, urinary stones and risk of cardiovascular diseases

Increased level of oxalates in urine and plasma can be attributed to endogenous overproduction, increased ingestion or excessive intestinal absorption. When a supersaturation status is reached, oxalates combine with calcium and crystallize to form 80% of the urinary stones. Several cardiovascular diseases such as coronary heart disease and stroke are thought to be associated with the formation of urinary stones via sharing the same pathogenesis and/or risk factors. This review investigated the evidence linking oxalates/urinary stones to cardiovascular diseases. Eventually, two theories can explain the possible association between urinary stones and cardiovascular diseases: the theory of common origin and the theory of common risk factors. While the first theory is based on the common vascular pathophysiology of urinary stones and cardiac events, the later suggests that metabolic syndrome traits increase the risk of urinary stones and cardiovascular diseases independently. A few cohort studies showed a higher risk of coronary heart disease and stroke among people with history of urinary stones than people without it while other cohort studies did not. These studies had different definitions for cardiovascular diseases, used various methods to assess urinary stones, and some of them did not control for potential confounders. When they were pooled together in meta-analyses, a significant heterogeneity across studies was observed. In conclusion, although there is some evidence indicating that urinary stones could increase the risk of cardiovascular diseases, a substantial causal relationship cannot be settled.

Low Bone Density and Bisphosphonate Use and the Risk of Kidney Stones

BACKGROUND AND OBJECTIVES

Previous studies have demonstrated lower bone density in patients with kidney stones, but no longitudinal studies have evaluated kidney stone risk in individuals with low bone density. Small studies with short follow-up reported reduced 24-hour urine calcium excretion with bisphosphonate use. We examined history of low bone density and bisphosphonate use and the risk of incident kidney stone as well as the association with 24-hour calcium excretion.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a prospective analysis of 96,092 women in the Nurses' Health Study II. We used Cox proportional hazards models to adjust for age, body mass index, thiazide use, fluid intake, supplemental calcium use, and dietary factors. We also conducted a cross-sectional analysis of 2294 participants using multivariable linear regression to compare 24-hour urinary calcium excretion between participants with and without a history of low bone density, and among 458 participants with low bone density, with and without bisphosphonate use.

RESULTS

We identified 2564 incident stones during 1,179,860 person-years of follow-up. The multivariable adjusted relative risk for an incident kidney stone for participants with history of low bone density compared with participants without was 1.39 (95% confidence interval [95% CI], 1.20 to 1.62). Among participants with low bone density, the multivariable adjusted relative risk for an incident kidney stone for bisphosphonate users was 0.68 (95% CI, 0.48 to 0.98). In the cross-sectional analysis of 24-hour urine calcium excretion, the multivariable adjusted mean difference in 24-hour calcium was 10 mg/d (95% CI, 1 to 19) higher for participants with history of low bone density. However, among participants with history of low bone density, there was no association between bisphosphonate use and 24-hour calcium with multivariable adjusted mean difference in 24-hour calcium of -2 mg/d (95% CI, -25 to 20).

CONCLUSIONS

Low bone density is an independent risk factor for incident kidney stone and is associated with higher 24-hour urine calcium excretion. Among participants with low bone density, bisphosphonate use was associated with lower risk of incident kidney stone but was not independently associated with 24-hour urine calcium excretion.

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.

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

PURPOSE

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

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Urinary Tract Stones and Osteoporosis: Findings From the Women's Health Initiative

Kidney and bladder stones (urinary tract stones) and osteoporosis are prevalent, serious conditions for postmenopausal women. Men with kidney stones are at increased risk of osteoporosis; however, the relationship of urinary tract stones to osteoporosis in postmenopausal women has not been established. The purpose of this study was to determine whether urinary tract stones are an independent risk factor for changes in bone mineral density (BMD) and incident fractures in women in the Women's Health Initiative (WHI). Data were obtained from 150,689 women in the Observational Study and Clinical Trials of the WHI with information on urinary tract stones status: 9856 of these women reported urinary tract stones at baseline and/or incident urinary tract stones during follow-up. Cox regression models were used to determine the association of urinary tract stones with incident fractures and linear mixed models were used to investigate the relationship of urinary tract stones with changes in BMD that occurred during WHI. Follow-up was over an average of 8 years. Models were adjusted for demographic and clinical factors, medication use, and dietary histories. In unadjusted models there was a significant association of urinary tract stones with incident total fractures (HR 1.10; 95% CI, 1.04 to 1.17). However, in covariate adjusted analyses, urinary tract stones were not significantly related to changes in BMD at any skeletal site or to incident fractures. In conclusion, urinary tract stones in postmenopausal women are not an independent risk factor for osteoporosis.

Leisure time physical activity, smoking and risk of recent symptomatic urolithiasis: Survey of stone clinic patients

INTRODUCTION

We explore relationships between selected lifestyle factors and recent (≤6 months) symptomatic urolithiasis (RSU).

METHODS

Surveys querying socio-demographic, medical history, physical activity, diet and smoking were administered to a convenience sample of stone clinic patients at a tertiary care hospital. Leisure time physical activity (LTPA) was assessed with the International Physical Activity Questionnaire (long form). Multivariate logistic regression was used to identify associations between risk factors and RSU.

RESULTS

Of the 163 participants, most were male (64%) and white (78%), with a mean (standard deviation) age of 56.3 (14.2) years. The mean body mass index (BMI) was 27.3 (5.4) kg/m(2) and 57 (35%) patients reported RSU. No significant (p < 0.05) differences were observed between participants with and without RSU in age, sex, ethnicity, BMI, or diet. Of the cohort, 52 (35%) participants met physical activity guidelines for walking (29%), moderate (27%) or vigorous activity (29%). LTPA did not differ significantly by RSU status. Compared to those without RSU, participants with RSU had higher rates of smoking (7% vs. 21%, p = 0.02 and had 8.5 (95% confidence interval 2.2-32.2) times the odds of being current smokers after controlling for sex, diet, and LTPA.

CONCLUSIONS

Physical inactivity and smoking are common among stone clinic patients, though LPTA was not associated with RSU. Study limitations include its small sample size, selection bias, and reliance on self-reported RSU (recall bias). In addition, participants may have already been following dietary recommendations to prevent urolithiasis recurrence. Nonetheless, current smoking was a potent predictor of RSU. When desired, smokers should be referred for smoking cessation.

Increased risk of bone fracture among patients with urinary calculi: a nationwide longitudinal population-based study

Urinary calculi were associated with higher risk of vertebral and upper limb fracture. Therefore, patients with urinary calculi should be evaluated carefully because they may have a higher risk of subsequent fracture later in life.

INTRODUCTION

The contribution of urinary calculi to reduced bone mineral density has been recognized. However, the association of urinary calculi with the risk of fracture remains inconclusive. The aim of the study was to determine the risk of overall fracture and fractures at different anatomic sites in patients with urinary calculi.

METHODS

The records of inpatients and outpatients with urinary calculi were retrieved from the Taiwan National Health Insurance Database from 2000 to 2010. Among patients with urinary calculi at the cohort entry, controls were matched using propensity scores on a 1:1 ratio. All subjects were followed up from the date of enrollment until fracture occurrence, death, or December 31, 2010. There were 46,243 Medicare beneficiaries with a diagnosis of urinary calculi and 46,243 controls without calculi enrolled.

RESULTS

Among these patients, 6005 patients with a diagnosis of urinary calculi and 5339 controls developed fractures during a median follow-up period of 5.3 years. Patients with urinary calculi had a higher incidence of fracture compared with controls (23.9 versus 22.1 per 1000 person-years) and a greater risk of overall fractures (adjusted hazard ratio [aHR] 1.08, 95 % confidence interval [CI], 1.04-1.12), mainly located at the vertebrae (aHR 1.15, 95 % CI, 1.06-1.25) and upper limb (aHR 1.07, 95 % CI, 1.01-1.14), but the risk for hip fracture was not increased (aHR 1.09, 95 % CI, 0.96-1.22).

CONCLUSIONS

Urinary calculus is independently associated with higher risk of subsequent fracture. Patients with urinary calculi should pay attention to the future vertebral and upper limb fractures.

Bone mineral density status in urolithiasis patients with vitamin D inadequacy followed at a tertiary stone centre

INTRODUCTION

We assessed abnormalities in bone mineral density (BMD) and the risk of hip and major osteoporotic fractures in urolithiasis patients with vitamin D inadequacy (VDI) followed at a tertiary stone centre.

METHODS

Stone-free patients with VDI were invited to undergo dual-energy x-ray absorptiometry (DXA) scans to assess for BMD abnormalities at the femoral neck and lumbar spine. The World Health Organization's validated Fracture Risk Assessment Tool (FRAX) was used to calculate the risk of hip and major osteoporotic fractures within 10 years. Patients with primary hyperparathyroidism or hypercalcemia were excluded.

RESULTS

In total, 50 consecutive patients were included between June 2011 and August 2012, including 26 (52%) males. The median age was 51 years and the median 25-hydroxyl vitamin D (25[OH] D) was 18.8 ng/mL. Thirty patients (60%) had abnormal T-scores on DXA studies. This decreased to 22 (44%) when age-matched Z-scores were used; 36% had osteopenia and 8% had osteoporosis. Femoral neck and lumbar spines were affected in 24% and 32% of patients, respectively. Recurrent stone-formers had significantly lower BMD when compared with first-time stone formers. Median serum 25(OH)D was comparable between patients with normal and abnormal DXA scans (18.6 vs. 18.8 ng/mL; p = 0.91). Five patients (10%) were at high risk (≥3%) of hip fractures within 10 years.

CONCLUSION

A high prevalence of abnormal DXA scans was found in urolithiasis patients with VDI, including 5 patients (10%) at high risk of hip fractures. Future studies need to assess the economic impact of obtaining DXA scans on urolithiasis patients with VDI, especially in recurrent stone-formers.

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.

Pediatric nephrolithiasis and the link to bone metabolism

PURPOSE OF REVIEW

To review the recent publications describing the link between pediatric nephrolithiasis and bone metabolism.

RECENT FINDINGS

Nephrolithiasis incidence is increasing in children and is associated with low bone mineral density (BMD). Affected children are conceptually at risk for fractures and osteoporosis. In addition to abnormal calcium metabolism, inflammation, genetic makeup and dietary habits are being recognized as important factors in the pathophysiology of nephrolithiasis and low bone density. Findings from retrospective reviews suggest that low BMD in children may be improved with citrate or thiazide treatment.

SUMMARY

The healthcare burden from low BMD with subsequent osteoporosis and fracture risk is immense with potential far-reaching effects in patient quality of life and healthcare expense. Bone mass is acquired in the pediatric age range, thus it is important to identify and treat at-risk children. Retrospective reviews in pediatric patients indicate that citrate or thiazide diuretic treatment may improve BMD. We now understand that a relationship exists between nephrolithiasis and low BMD. To improve healthcare for our current patients as well as protect their future health it is important to identify low BMD and initiate strategies to improve BMD in 'at-risk' children.