Renal Function and Bone Loss in a Cohort of Afro-Caribbean Men

Osteoporosis management in patients with chronic kidney disease (ERCOS Study): A challenge in nephrological care

Fracture risk assessment in patients with chronic kidney disease (CKD) has been included in the CKD-MBD ("Chronic Kidney Disease-Mineral and Bone Disorders") complex in international and national nephrology guidelines, suggesting for the first time the assessment of bone mineral density (BMD) if the results can influence therapeutic decision-making. However, there is very little information on actual clinical practice in this population. The main objective of the ERCOS (ERC-Osteoporosis) study is to describe the profile of patients with CKD G3-5D with osteoporosis (OP) and/or fragility fractures treated in specialized nephrology, rheumatology and internal medicine clinics in Spain. Fifteen centers participated and 162 patients (mostly women [71.2%] postmenopausal [98.3%]) with a median age of 77 years were included. Mean estimated glomerular filtration rate (eGFR) was 36 mL/min/1.73 m2 and 38% of the included patients were on dialysis. We highlight the high frequency of prevalent fragility fractures [37.7%), mainly vertebral (52.5%) and hip (24.6%)], the disproportionate history of patients with glomerular disease compared to purely nephrological series (corticosteroids) and undertreatment for fracture prevention, especially in nephrology consultations. This study is an immediate call to action with the dissemination of the new, more proactive, clinical guidelines, and underlines the need to standardize a coordinated and multidisciplinary care/therapeutic approach to these patients in an efficient way to avoid current discrepancies and therapeutic nihilism.

Meta-analyses of the quantitative computed tomography data in dialysis patients show differential impacts of renal failure on the trabecular and cortical bones

Dialysis patients have compromised bone health that increases their fracture risk due to low bone mass and deterioration in bone microarchitecture. Through meta-analyses of published studies, we conclude that dialysis patients suffer from impaired compartmental bone parameters compared with healthy controls.

INTRODUCTION

We performed meta-analyses to determine the effect of chronic kidney disease (CKD) patients under dialysis on the trabecular and cortical parameters of radius and tibia.

METHODS

This is a meta-analysis of cross-sectional and prospective clinical studies. PubMed, Web of Science, Google Scholar, and Scopus were searched using various permutation combinations. Dialysis patients were compared with non-CKD healthy controls using quantitative computed tomography. High-resolution peripheral quantitative computed tomography (HR-pQCT) and pQCT data of dialysis patients were dissected from eligible studies for pooled analysis of each parameter.

RESULTS

Ten studies met the inclusion criteria that included data from 457 dialysis patients and 2134 controls. Pooled analysis showed a significant decrease (a) in total vBMD at distal radius [standard deviation of the mean (SDM) = -0.842, p = 0.000] and tibia (SMD = -0.705, p = 0.000) and (b) in cortical vBMD (SDM = -1.037, p = 0.000) at radius of dialysis patients compared with control. There were strong correlations between total vBMD and microarchitecture parameters at tibia in dialysis patients.

CONCLUSIONS

At radius and tibia, bone mass, microarchitecture, and geometry at trabecular and cortical envelopes displayed impairments in dialysis patients compared with control. Tibial vBMD may have diagnostic value in dialysis. HR-pQCT and pQCT may be used to further understand the compartmental bones response to CKD-induced loss at different stages of CKD.

Replacing sedentary time for physical activity on bone density in patients with chronic kidney disease

INTRODUCTION

This study aimed to examine the cross-sectional associations of sedentary time and physical activity time with bone density in patients with chronic kidney disease (CKD). The isotemporal substitution (IS) modeling was used to estimate the beneficial effects of behavioral changes (e.g., replacing sedentary time with physical activity time) on bone density in these patients.

MATERIALS AND METHODS

A total of 92 patients with CKD (age: 65 ± 9 years; estimated glomerular filtration rate: 57 ± 22 mL/min/1.73 m²) were included in this cross-sectional study. The times spent in sedentary behavior (SB), light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) were assessed using a triaxial accelerometer. Through quantitative ultrasound measurements, the stiffness index, as a measure of bone density, was calculated using the speed of sound and broadband ultrasound attenuation.

RESULTS

In multivariate analyses, the stiffness index was beneficially associated with the MVPA time (β = 0.748), but was not significantly associated with the SB and LPA times. The IS models showed that replacing 10 min/day of SB with the equivalent LPA time was not significantly associated with the stiffness index; however, replacing 10 min/day of SB with the equivalent MVPA time was beneficially associated with the stiffness index (β = 0.804).

CONCLUSION

These results suggest that a small increase in MVPA time (e.g., 10 min/day) may attenuate the decline in bone density in patients with CKD. Our findings may provide insight for the development of novel strategies for improving bone health in patients with CKD.

Predictive value of quantitative ultrasound parameters in individuals with chronic kidney disease: A population-based analysis of CARTaGENE

BACKGROUND

The use of calcaneal quantitative ultrasound (QUS) to predict fractures has not been well studied in early CKD populations. We compared the association of QUS with incidental fractures and its predictive properties in non-CKD and CKD individuals.

METHODS

Analysis of a prospective population-based survey of 40- to 69-year-old individuals recruited between 2009 and 2010. QUS parameters (stiffness index [SI], speed of sound [SOS], broadband attenuation [BUA]) were measured at baseline. Renal function was measured using baseline creatinine and was classified into CKD stages (non-CKD, stage 2, stage 3). Fracture incidence at any site or at major osteoporotic fracture sites for up to 7 years of follow-up was identified in administrative databases using a validated algorithm. The association (age-adjusted hazard ratio per standard deviation decrease in Cox models), discrimination (c-statistic) and calibration (standardized incidence ratio [SIR]) of QUS parameters with fracture outcomes was computed in each CKD stratum.

RESULTS

We included 18,306 individuals (9,011 non-CKD; 8,595 CKD stage 2; 700 CKD stage 3). During a median follow-up of 70 months, we identified 782 fractures at any site and 326 major osteoporotic fractures. Although all QUS parameters (SI, SOS and BUA) were associated with any or major fracture incidence in non-CKD and CKD patients, the magnitude of these associations was lower for any fracture and for BUA. QUS parameters moderately discriminated incidental fractures across CKD strata but underestimated fracture incidence in CKD stage 3 even after adjustment for demographics and clinical risk factors. At a given QUS value, CKD stage 3 patients had higher fracture risk than non-CKD and CKD stage 2 patients.

CONCLUSIONS

QUS parameters are associated with fracture incidence in both non-CKD and CKD but underestimate fracture incidence in individuals with early CKD.

Association of renal function with bone mineral density and fracture risk in the Longitudinal Aging Study Amsterdam

Early renal dysfunction is associated with a 38% increased fracture risk in individuals aged 65 years and older. In men but not women, early renal dysfunction is associated with decreased femoral neck bone mineral density (BMD) which can be partially explained by increased parathyroid hormone (PTH) concentrations.

INTRODUCTION

It is uncertain whether early renal dysfunction is associated with osteoporosis and increased fracture risk. The aim of this study was to determine the relationship of decreased renal function with BMD and fracture risk and the role of PTH therein.

METHODS

We analyzed data of participants aged 65 years and older from the Longitudinal Aging Study Amsterdam. A 6-year fracture follow-up was obtained in 1477 participants. BMD was measured by dual-energy x-ray absorptiometry (n = 535) and vertebral fractures by lateral spinal radiograph (n = 527) in a subsample at baseline. Glomerular filtration rate (eGFR) was estimated according to the modification of diet in renal disease equation and assessed by the five stages of chronic kidney disease (CKD).

RESULTS

In men and women, eGFR < 57 ml/min/1.73 m2 (lowest quartile) compared to eGFR > 74 ml/min/1.73 m2 (highest quartile) was associated with a 38% increase in fracture risk after adjustment for relevant confounders [hazard ratio (95%CI): 1.38 (1.17 to 1.61)]. Also, CKD stages 3a and 3b were associated to a 28 and 46% increase in fracture risk, respectively, as compared to CKD stages 1 and 2 together (eGFR > 60 ml/min/1.73 m2) after adjustment for confounders. Renal function was not associated with prevalent vertebral fractures. In men, but not women, lowest quartile of eGFR was related to lower femoral neck BMD as compared to the highest quartile eGFR [unstandardized B (95%CI) - 0.052 g/cm2 (- 0.098 to - 0.006)], after adjustment for relevant confounders. Further adjustment for PTH attenuated this relationship by 27%.

CONCLUSIONS

In men and women, early decreased renal function (eGFR < 60 ml/min/1.73 m2) was related to increased incident any fracture risk but not with increased prevalence of vertebral fractures. In men, but not women, early renal dysfunction was related to lower femoral neck BMD which could statistically be partially explained by increased PTH concentrations.

Osteoporosis, bone mineral density and CKD-MBD complex (I): Diagnostic considerations

Osteoporosis (OP) and chronic kidney disease (CKD) independently influence bone and cardiovascular health. A considerable number of patients with CKD, especially those with stages 3a to 5D, have a significantly reduced bone mineral density leading to a high risk of fracture and a significant increase in associated morbidity and mortality. Independently of classic OP related to age and/or gender, the mechanical properties of bone are also affected by inherent risk factors for CKD ("uraemic OP"). In the first part of this review, we will analyse the general concepts regarding bone mineral density, OP and fractures, which have been largely undervalued until now by nephrologists due to the lack of evidence and diagnostic difficulties in the context of CKD. It has now been proven that a reduced bone mineral density is highly predictive of fracture risk in CKD patients, although it does not allow a distinction to be made between the causes which generate it (hyperparathyroidism, adynamic bone disease and/or senile osteoporosis, etc.). Therefore, in the second part, we will analyse the therapeutic indications in different CKD stages. In any case, the individual assessment of factors which represent a higher or lower risk of fracture, the quantification of this risk (i.e. using tools such as FRAX^®) and the potential indications for densitometry in patients with CKD could represent an important first step pending new clinical guidelines based on randomised studies which do not exclude CKD patients, all the while avoiding therapeutic nihilism in an area of growing importance.

The Relationship between Renal Function and Bone Marrow Density in Healthy Korean Women

OBJECTIVES

The relationship between renal function and bone mineral density (BMD) is controversial. We evaluated the relationship between markers of renal function and BMD in healthy Korean women.

METHODS

A total of 1,093 women who visited the health promotion center at Pusan National University hospital were included in the cross-sectional study. We divided the study population into two groups by BMD: osteopenia-osteoporosis and normal in the lumbar and femur regions, respectively. We compared the relationship between renal function and BMD using a logistic regression model and used SAS 9.3 (SAS Institute, Inc., Cary, NC, USA) for all statistical analysis.

RESULTS

Blood urea nitrogen (BUN), creatinine, and cystatin C (Cys-C) were correlated with BMD in both the normal and osteopenia-osteoporosis groups, and in logistic regression analysis, BUN and Cys-C were correlated with lumbar and femur BMD. However, after we adjusted for age, menopause, and body mass index, only creatinine showed a negative correlation with lumbar BMD, and estimated glomerular filtration rate (eGFR) was related positively with femur BMD.

CONCLUSIONS

Serum creatinine could be a marker for lumbar BMD and eGFR for femur BMD in Korean women without overt nephropathy.

Association of Increased Urinary Albumin With Risk of Incident Clinical Fracture and Rate of Hip Bone Loss: the Osteoporotic Fractures in Men Study

Prior studies suggest that increased urine albumin is associated with a heightened fracture risk in women, but results in men are unclear. We used data from Osteoporotic Fractures in Men (MrOS), a prospective cohort study of community-dwelling men aged ≥65 years, to evaluate the association of increased urine albumin with subsequent fractures and annualized rate of hip bone loss. We calculated albumin/creatinine ratio (ACR) from urine collected at the 2003-2005 visit. Subsequent clinical fractures were ascertained from triannual questionnaires and centrally adjudicated by review of radiographic reports. Total hip BMD was measured by DXA at the 2003-2005 visit and again an average of 3.5 years later. We estimated risk of incident clinical fracture using Cox proportional hazards models, and annualized BMD change using ANCOVA. Of 2982 men with calculable ACR, 9.4% had ACR ≥30 mg/g (albuminuria) and 1.0% had ACR ≥300 mg/g (macroalbuminuria). During a mean of 8.7 years of follow-up, 20.0% of men had an incident clinical fracture. In multivariate-adjusted models, neither higher ACR quintile (p for trend 0.75) nor albuminuria (HR versus no albuminuria, 0.89; 95% CI, 0.65 to 1.20) was associated with increased risk of incident clinical fracture. Increased urine albumin had a borderline significant, multivariate-adjusted, positive association with rate of total hip bone loss when modeled in ACR quintiles (p = 0.06), but not when modeled as albuminuria versus no albuminuria. Macroalbuminuria was associated with a higher rate of annualized hip bone loss compared to no albuminuria (-1.8% more annualized loss than in men with ACR <30 mg/g; p < 0.001), but the limited prevalence of macroalbuminuria precluded reliable estimates of its fracture associations. In these community-dwelling older men, we found no association between urine albumin levels and risk of incident clinical fracture, but found a borderline significant, positive association with rate of hip bone loss. © 2016 American Society for Bone and Mineral Research.

Evaluation of fracture risk in chronic kidney disease

Chronic kidney disease (CKD) is associated with mineral and bone disorders (MBD) that are now considered as a syndrome. Bone fragility and a four to tenfold increased rate of skeletal fractures are often reported in CKD patients. The evaluation of the risk of these fractures in CKD patients should explore the same risk factors identified for the general population including low body weight, menopause, personal and familial history of osteoporosis, chronic inflammatory diseases, and corticosteroid therapy. The aim of this article is to provide a critical review of the tools used for the evaluation of bone loss and the risk of fracture in CKD patients, ranging from the measurement of bone mineral density (BMD), fracture risk assessment (Frax™), quantitative computed tomography (QCT), high-resolution peripheral quantitative computed tomography (HRpQTC), to circulating biomarkers of bone metabolism including vitamin D, parathyroid hormone (PTH), bone-specific alkaline phosphatase, osteocalcin, and some collagen type 1-related molecules indicators of bone remodeling.