Osteoporotic fractures in patients with systemic lupus erythematosus and end stage renal disease

Ten tips on how to assess bone health in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) experience a several-fold increased risk of fracture. Despite the high incidence and the associated excess morbidity and premature mortality, bone fragility in CKD, or CKD-associated osteoporosis, remains a blind spot in nephrology with an immense treatment gap. Defining the bone phenotype is a prerequisite for the appropriate therapy of CKD-associated osteoporosis at the patient level. In the present review, we suggest 10 practical 'tips and tricks' for the assessment of bone health in patients with CKD. We describe the clinical, biochemical, and radiological evaluation of bone health, alongside the benefits and limitations of the available diagnostics. A bone biopsy, the gold standard for diagnosing renal bone disease, is invasive and not widely available; although useful in complex cases, we do not consider it an essential component of bone assessment in patients with CKD-associated osteoporosis. Furthermore, we advocate for the deployment of multidisciplinary expert teams at local, national, and potentially international level. Finally, we address the knowledge gaps in the diagnosis, particularly early detection, appropriate "real-time" monitoring of bone health in this highly vulnerable population, and emerging diagnostic tools, currently primarily used in research, that may be on the horizon of clinical practice.

Secondary Osteoporosis and Metabolic Bone Diseases

Fragility fracture is a worldwide problem and a main cause of disability and impaired quality of life. It is primarily caused by osteoporosis, characterized by impaired bone quantity and or quality. Proper diagnosis of osteoporosis is essential for prevention of fragility fractures. Osteoporosis can be primary in postmenopausal women because of estrogen deficiency. Secondary forms of osteoporosis are not uncommon in both men and women. Most systemic illnesses and organ dysfunction can lead to osteoporosis. The kidney plays a crucial role in maintaining physiological bone homeostasis by controlling minerals, electrolytes, acid-base, vitamin D and parathyroid function. Chronic kidney disease with its uremic milieu disturbs this balance, leading to renal osteodystrophy. Diabetes mellitus represents the most common secondary cause of osteoporosis. Thyroid and parathyroid disorders can dysregulate the osteoblast/osteoclast functions. Gastrointestinal disorders, malnutrition and malabsorption can result in mineral and vitamin D deficiencies and bone loss. Patients with chronic liver disease have a higher risk of fracture due to hepatic osteodystrophy. Proinflammatory cytokines in infectious, autoimmune, and hematological disorders can stimulate osteoclastogenesis, leading to osteoporosis. Moreover, drug-induced osteoporosis is not uncommon. In this review, we focus on causes, pathogenesis, and management of secondary osteoporosis.

Traditional and Non-traditional Risk Factors for Osteoporosis in CKD

Osteoporosis is a state of bone fragility with reduced skeletal resistance to trauma, and consequently increased risk of fracture. A wide range of conditions, including traditional risk factors, lifestyle choices, diseases and their treatments may contribute to bone fragility. It is therefore not surprising that the multi-morbid patient with chronic kidney disease (CKD) is at a particularly high risk. CKD is associated with reduced bone quantity, as well as impaired bone quality. Bone fragility in CKD is a composite of primary osteoporosis, accumulation of traditional and uremia-related risk factors, assaults brought on by systemic disease, and detrimental effects of drugs. Some risk factors are modifiable and represent potential targets for intervention. This review provides an overview of the heterogeneity of bone fragility in CKD.

Fractures in patients with rheumatoid arthritis and end-stage renal disease

Having rheumatoid arthritis (RA) or end-stage renal disease (ESRD) can lead to fractures. RA independently increases the risk of hip or other femur fracture in dialysis patients. Use of corticosteroids is a potentially modifiable risk factor for fractures among persons with RA and ESRD on dialysis.

PURPOSE

Rheumatoid arthritis (RA) and end-stage renal disease (ESRD) both independently increase fracture risk; however, how RA and ESRD interplay to affect fracture risk is unknown. We aim to determine the association of RA with fracture in ESRD and identify risk factors for fracture in patients with RA and ESRD.

METHODS

A retrospective cohort study was conducted using the United States Renal Data System (USRDS) to identify ESRD adults with and without a history of RA who initiated dialysis in 2005-2008. International Classification of Diseases, 9th Revision (ICD-9) codes were used to identify fractures following start of dialysis. Risk for incident fracture was compared between those with and without RA. Potential risk factors for fracture among persons with RA and ESRD were analyzed.

RESULTS

There were 754 persons with ESRD and RA, of whom 126 (17%) had any incident fracture. In multivariable adjusted final models, among ESRD patients, RA was an independent risk factor for hip/femur fracture (RR 1.28, 95% CI 1.01-1.64). Among persons with RA and ESRD, in final models, only corticosteroid use was a significant risk factor for both any incident (RR 2.00, 95% CI 1.40-2.87) and hip/femur (RR 1.97, 95% CI 1.24-3.11) fracture. Those with higher body mass index had a lower relative risk of hip/femur fracture (RR 0.95, 95% CI 0.91-0.99).

CONCLUSION

Among ESRD patients, those with RA have a 28% increased risk for hip or other femur fracture. Use of corticosteroids is a potentially modifiable risk factor for fractures among persons with RA and ESRD.

A meta-analysis of secondary osteoporosis in systemic lupus erythematosus: prevalence and risk factors

PURPOSE

This study aimed to evaluate the prevalence and risk factors of secondary osteoporosis (OP) in patients with systemic lupus erythematosus (SLE) and provide a theoretical basis for clinical prevention and treatment of SLE.

METHODS

Take systematic review and meta-analysis of relevant studies. Data sources are CINAHL databases, PubMed, Embase, Wan Fang, Weipu, and CNKI databases. Eligibility criteria are cross-sectional or case-control studies which analyzed the prevalence and risk factors of OP in SLE. Two authors independently screened all studies; a third author verified and identify controversial studies. The quality of the included articles was evaluated. Stata 11 and Rev-Man 5.2 software were used for data processing.

RESULTS

Thirty-one articles were included, with a total sample size of 3089 SLE, including 529 OP cases and 2560 non-OP cases. Meta-analysis showed that the prevalence of OP among SLE was 16% (95% CI (0.12, 0.19)). The risk of OP in SLE cases compared with controls was significantly greater with OR of 2.03 (95% CI 1.33-3.10, P = 0.001). Age, disease duration, cumulative glucocorticoid dose, duration of glucocorticoid therapy, SLICC, and menopause had significant differences between two groups. No statistical differences of daily glucocorticoid dose, SLEDAI, and BMI were found between OP and non-OP cases.

CONCLUSIONS

Our study found a statistically significant increased risk of OP in SLE patients compared with controls. SLE patients should be actively screened for OP and its consequences. Larger longitudinal studies are needed to confirm this possible association. The prevalence of OP in SLE was 16%. Compared with controls, the risk of OP in SLE was 2.03. There were significant differences of age, disease duration, cumulative glucocorticoid dose, time of glucocorticoid, SLICC, and menopause, while daily glucocorticoid dose, SLEDAI, and BMI had no statistical differences between OP and non-OP cases.

Comparative Fracture Risks Among United States Medicaid Enrollees With and Those Without Systemic Lupus Erythematosus

OBJECTIVE

Poor bone health is common in systemic lupus erythematosus (SLE) patients. This study was undertaken to evaluate fracture risks among low-income SLE and lupus nephritis patients compared to those without SLE.

METHODS

We performed a cohort study among SLE patients for whom there were Medicaid claims in 2007-2010, and age- and sex-matched non-SLE comparators. SLE was defined by the presence of ≥3 International Classification of Diseases, Ninth Revision codes for SLE. Patients with lupus nephritis additionally had ≥2 codes for renal disease. The primary outcome measure was fracture of the pelvis, wrist, hip, or humerus. Demographics, prescriptions, and comorbidities were assessed during the 180-day baseline period. We calculated fracture incidence rates and 95% confidence intervals (95% CIs) in SLE, lupus nephritis, and non-SLE comparator cohorts, and estimated adjusted hazard ratios (HRs) for fractures. Sensitivity analyses evaluated the impact of glucocorticoids and comorbidities. We compared subsets of SLE patients with and those without lupus nephritis.

RESULTS

Among 47,709 SLE patients (19.8% with lupus nephritis) matched to 190,836 non-SLE comparators, the mean age was 41.4 years and 92.6% were female. The fracture incidence rate was highest among SLE patients with lupus nephritis (4.60 per 1,000 person-years). SLE patients had 2-fold higher fracture risks than matched comparators (HR 2.09 [95% CI 1.85-2.37]; P < 0.01). Lupus nephritis patients had the greatest fracture risks versus matched comparators (HR 3.06 [95% CI 2.24-4.17]; P < 0.01), and had a 1.6 times higher fracture risk than SLE patients without nephritis (HR 1.58 [95% CI 1.20-2.07]; P < 0.01). Adjustment for glucocorticoid use and comorbidities slightly attenuated risks.

CONCLUSION

Fracture risks were increased in SLE patients, particularly those with lupus nephritis, compared to matched non-SLE Medicaid recipients. Increased risks persisted after adjustment for baseline glucocorticoid treatment and comorbidities.