THE EFFECTS OF HYPONATREMIA ON BONE DENSITY AND FRACTURES: A SYSTEMATIC REVIEW AND META-ANALYSIS

The Influence of Hyponatremia and Hypokalemia on the Risk of Fractures in Various Anatomical Regions among Adult Trauma Patients: A Propensity Score-Matched Analysis

BACKGROUND

Hyponatremia and hypokalemia are common electrolyte imbalances in trauma patients and have been identified to be risk factors for a fall. In addition, hyponatremia was reported to be related to osteoporosis and fragility fractures, while the association between hypokalemia and osteoporosis has only been reported in rare case reports. This study investigated the impact of hyponatremia and hypokalemia on the incidence of fractures in various body regions of adult trauma patients, using the propensity score-matched patient cohort to reduce the influence of patients' baseline characteristics.

METHODS

The study analyzed data from 11,173 hospitalized adult trauma patients treated from 1 January 1998, to 31 December 2022. The study included 1968 patients with hyponatremia and 9205 without, and 1986 with hypokalemia and 9187 without. Different 1:1 propensity score-matched cohorts were generated to create the 1903 pairings of patients with or without hyponatremia, 1977 pairings of patients with or without hypokalemia, and 380 pairing of patients with both hyponatremia and hypokalemia vs. normal control patients. Analysis was conducted on the incidence of fracture in various anatomic regions.

RESULTS

Hyponatremic patients had increased odds of thoracic vertebral fracture [odds ratio (95% confidence interval) 1.63 (1.10-2.42), p = 0.014], pelvic fracture [2.29 (1.12-4.67), p = 0.019], and femoral fracture [1.28 (1.13-1.45), p < 0.001] but decreased odds of radial and patella fractures. Hypokalemic patients showed no significant differences in fracture risk except for a decreased likelihood of radial fractures. The patients with both hyponatremia and hypokalemia showed a decreased likelihood of radial fractures and patella fractures.

CONCLUSION

Hyponatremia may have a greater impact on the occurrence of bone fractures than hypokalemia in trauma patients who have suffered a fall. Electrolyte abnormalities should be taken into account while assessing the risk of fractures in trauma patients.

Pituitary crosstalk with bone, adipose tissue and brain

Traditional textbook physiology has ascribed unitary functions to hormones from the anterior and posterior pituitary gland, mainly in the regulation of effector hormone secretion from endocrine organs. However, the evolutionary biology of pituitary hormones and their receptors provides evidence for a broad range of functions in vertebrate physiology. Over the past decade, we and others have discovered that thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone, prolactin, oxytocin and arginine vasopressin act directly on somatic organs, including bone, adipose tissue and liver. New evidence also indicates that pituitary hormone receptors are expressed in brain regions, nuclei and subnuclei. These studies have prompted us to attribute the pathophysiology of certain human diseases, including osteoporosis, obesity and neurodegeneration, at least in part, to changes in pituitary hormone levels. This new information has identified actionable therapeutic targets for drug discovery.

Prevalence of hyponatremia and associated factors in patients with chronic kidney disease: the Fukuoka Kidney Disease Registry (FKR) study

BACKGROUND

Hyponatremia is a common and important electrolyte disorder. However, the prevalence and factors associated with hyponatremia in patients with chronic kidney disease (CKD) are unknown.

METHODS

We studied the factors associated with hyponatremia (< 135 mEq/L) in CKD patients registered in the Fukuoka Kidney Disease Registry (FKR) study using a logistic regression model variable selected using the variable reduction method.

RESULTS

We analyzed the baseline characteristics of 4367 participants with CKD (age, 64 ± 16 years; male, 56.1%). Hyponatremia was detected in 2.0% of the patients at baseline, and multivariate logistic analysis showed that the independent factors for hyponatremia were body mass index (odds ratio [OR] 0.91; 95% confidence interval [CI] 0.85-0.97), prescription of benzodiazepine (OR 2.31; 95% CI 1.39-3.86), blood hemoglobin level (OR 0.76; 95% CI 0.65-0.88), and serum C-reactive protein level (OR 1.27; 95% CI 1.04-1.54).

CONCLUSION

The cross-sectional analysis using baseline data from the FKR study revealed independent factors associated with hyponatremia in patients with decreased kidney function. Longitudinal analyses of the FKR cohort are needed to evaluate the effects of these factors on the prognosis of hyponatremia in patients with CKD.

Association of hyponatremia with bone mineral density and fractures: a narrative review

Recent studies suggest a possible association of hyponatremia with osteoporosis, falls and bone fractures. The objectives of this narrative review were to further explore this association and the related pathophysiological mechanisms and to suggest a practical approach to patients with osteoporosis or chronic hyponatremia in clinical practice. We conducted an extensive PubMed search until October 2022 with the combination of the following keywords: 'hyponatremia' or 'sodium' or 'SIADH' and 'fractures' or 'bone' or 'osteoporosis', as MeSH Terms. Review of numerous observational studies confirms a significant independent association of, even mild, hyponatremia with two- to three-fold increase in the occurrence of bone fractures. Hyponatremia is a risk factor for osteoporosis with a predilection to affect the hip, while the magnitude of association depends on the severity and chronicity of hyponatremia. Chronic hyponatremia also increases the risk for falls by inducing gait instability and neurocognitive deficits. Besides the detrimental impact of hyponatremia on bone mineral density and risk of falls, it also induces changes in bone quality. Emerging evidence suggests that acute hyponatremia shifts bone turnover dynamics towards less bone formation, while hyponatremia correction increases bone formation. The key unanswered question whether treatment of hyponatremia could improve osteoporosis and lower fracture risk highlights the need for prospective studies, evaluating the impact of sodium normalization on bone metabolism and occurrence of fractures. Recommendations for clinical approach should include measurement of serum sodium in all individuals with fracture or osteoporosis. Also, hyponatremia, as an independent risk factor for fracture, should be taken into consideration when estimating the likelihood for future fragility fracture and in clinical decision-making about pharmacological therapy of osteoporosis. Until it is proven that normalization of sodium can lower fracture occurrence, correcting hyponatremia cannot be universally recommended on this basis, but should be decided on a case-by-case basis.

Recent advances in the identification of related factors and preventive strategies of hip fracture

Hip fracture is the most devastating type of osteoporosis-related fracture, and is a major worldwide public health problem with a high socioeconomic burden, morbidity rate, and mortality rate. Thus, it is crucial to uncover the risk factors and protective factors to create a hip fracture prevention strategy. In addition to a briefly review of some well accepted risk and protective factors of hip fracture, this review mainly summarized the recent advances in the identification of emerging risk or protective factors for hip fracture, in terms of regional differences in medical services, diseases, drugs, mechanical load, neuromuscular mass, genes, blood types, cultural differences. This review provides a comprehensive review of the associated factors and effective prevention measures for hip fracture, and discusses issues that need further investigation. These issues include the determination of the influencing mechanism of risk factors triggering hip fracture and their interlinked correlation with other factors, as well as the confirmation or correction of emerging factors associated with hip fracture, particularly those that are still controversial. These recent findings will aid in optimizing the strategy for preventing hip fracture.

Development and Internal Validation of a Nomogram to Predict Mortality During the ICU Stay of Thoracic Fracture Patients Without Neurological Compromise: An Analysis of the MIMIC-III Clinical Database

Background: This study aimed to develop and validate a nomogram for predicting mortality in patients with thoracic fractures without neurological compromise and hospitalized in the intensive care unit. Methods: A total of 298 patients from the Medical Information Mart for Intensive Care III (MIMIC-III) database were included in the study, and 35 clinical indicators were collected within 24 h of patient admission. Risk factors were identified using the least absolute shrinkage and selection operator (LASSO) regression. A multivariate logistic regression model was established, and a nomogram was constructed. Internal validation was performed by the 1,000 bootstrap samples; a receiver operating curve (ROC) was plotted, and the area under the curve (AUC), sensitivity, and specificity were calculated. In addition, the calibration of our model was evaluated by the calibration curve and Hosmer-Lemeshow goodness-of-fit test (HL test). A decision curve analysis (DCA) was performed, and the nomogram was compared with scoring systems commonly used during clinical practice to assess the net clinical benefit. Results: Indicators included in the nomogram were age, OASIS score, SAPS II score, respiratory rate, partial thromboplastin time (PTT), cardiac arrhythmias, and fluid-electrolyte disorders. The results showed that our model yielded satisfied diagnostic performance with an AUC value of 0.902 and 0.883 using the training set and on internal validation. The calibration curve and the Hosmer-Lemeshow goodness-of-fit (HL). The HL tests exhibited satisfactory concordance between predicted and actual outcomes (P = 0.648). The DCA showed a superior net clinical benefit of our model over previously reported scoring systems. Conclusion: In summary, we explored the incidence of mortality during the ICU stay of thoracic fracture patients without neurological compromise and developed a prediction model that facilitates clinical decision making. However, external validation will be needed in the future.

Lower Oxytocin Levels Are Associated with Lower Bone Mineral Density and Less Favorable Hip Geometry in Hypopituitary Men

INTRODUCTION

Hypopituitary patients are at risk for bone loss. Hypothalamic-posterior pituitary hormones oxytocin and vasopressin are anabolic and catabolic, respectively, to the skeleton. Patients with hypopituitarism may be at risk for oxytocin deficiency. Whether oxytocin and/or vasopressin contribute to impaired bone homeostasis in hypopituitarism is unknown.

OBJECTIVES

To determine the relationship between plasma oxytocin and vasopressin levels and bone characteristics (bone mineral density [BMD] and hip structural analysis [HSA]) in patients who have anterior pituitary deficiencies only (APD group) or with central diabetes insipidus (CDI group).

METHODS

This is a cross-sectional study. Subjects included 37 men (17 CDI and 20 APD), aged 20-60 years. Main outcome measures were fasting plasma oxytocin and vasopressin levels, and BMD and HSA using dual X-ray absorptiometry.

RESULTS

Mean BMD and HSA variables did not differ between the CDI and APD groups. Mean BMD Z-scores at most sites were lower in those participants who had fasting oxytocin levels below, rather than above, the median. There were positive associations between fasting oxytocin levels and (1) BMD Z-scores at the spine, femoral neck, total hip, and subtotal body and (2) favorable hip geometry and strength variables at the intertrochanteric region in CDI, but not APD, participants. No associations between vasopressin levels and bone variables were observed in the CDI or ADP groups.

CONCLUSIONS

This study provides evidence for a relationship between oxytocin levels and BMD and estimated hip geometry and strength in hypopituitarism with CDI. Future studies will be important to determine whether oxytocin could be used therapeutically to optimize bone health in patients with hypopituitarism.

Effects of androgen excess and glucocorticoid exposure on bone health in adult patients with 21-hydroxylase deficiency

CONTEXT

This study aimed to determine the role of modifiable predictors on bone health in congenital adrenal hyperplasia (CAH).

DESIGN

Cross-sectional, single center study, including 97 patients (N = 42 men) with classic CAH due to 21-hydroxylase deficiency (N = 65 salt wasting, N = 32 simple virilizing).

MAIN OUTCOME MEASURES

Treatment-related predictors of bone health.

RESULTS

Average T scores (-0.9 ± 1.4 vs. -0.4 ± 1.4; p = 0.036) as well as Z scores (-1.0 ± 1.3 vs. -0.1 ± 1.4; p = 0.012) at the spine in patients with CAH were significantly lower in men than women. While osteoporosis was rare in women, it was documented in 9.1% of men with CAH. There was a significant positive correlation of Z scores at the spine with advancing age in women with CAH (R² = 0.178; p = 0.003). In multivariate analysis, the intake of conventional hydrocortisone (HC) instead of synthetic glucocorticoids was independently associated with a higher bone mineral density (BMD) at the hip region in both sexes. In women, there was a positive association with vitamin D concentrations. Interestingly, higher sodium levels were associated with a lower BMD independent of renin levels and fludrocortisone dosage. Neither in men nor in women, markers of androgen control were predictive for BMD at any site. Markers of bone turnover indicated low bone turnover. No pathological fractures were documented.

CONCLUSIONS

Men with CAH are particularly prone to low bone density, while women seem to be relatively protected by androgen excess compared to the general female population. The use of HC instead of synthetic GCs for hormone replacement may translate into better bone health.

Characteristics of very elderly patients in the emergency department - A retrospective analysis

INTRODUCTION

Elderly people, defined by age 65 years and older, made up 18.45% of the Swiss Population in 2018 and their number is projected to rise continuously. Data investigating specific characteristics of this patient subgroup, especially in the emergency setting, is scarce.

METHODS

Demographic data of admission records from all patients aged 65 years or older admitted to our emergency department (ED) between January 1st 2015 and December 31st 2018 were investigated. Retrospective chart reviews of patients admitted in 2018 were conducted. Comorbidity burden was assessed by Charlson Comorbidity Index. Risk factors for death, longer hospitalization and placement in a nursing facility were identified by multivariate regression.

RESULTS

The prevalence of elderly patients (≥65 years) admitted to the ED between 2015 and 2018 was rising from 33% in 2015 to 37.8% in 2018. In 2018 709 patients were 90 years and older (3.6%). Age above 90 years and high comorbidity burden were identified as independent risk factors for death. Polypharmacy, hyponatremia and high comorbidity burden were independent risk factors for longer hospitalizations. Advanced age and high comorbidity burden were independent risk factors for placement in a nursing facility.

CONCLUSION

The number of elderly patients admitted to our ED is continuously rising. There was no difference in overall disease burden, number of medications and hospital length of stay between octogenarians and nonagenarians. We identified risk factors for mortality, long hospitalizations and need of placement in a nursing facility.

Fragility fractures and reversible osteopaenia due to chronic hyponatraemia in an adolescent male

Fragility fractures are common in older adults and rare in children. Recent studies have demonstrated that hyponatraemia is a novel risk factor for the development of osteoporosis and hip fractures in older people. Animal studies suggest that hyponatraemia can lead to decreased bone mineral density by stimulating osteoclastic activity in order to mobilise sodium from the bone. Reported is a 16-year-old man with intractable epilepsy and an 11-year history of chronic hyponatraemia (126-135 mEq/L) due to valproic acid induced syndrome of inappropriate antidiuresis who sustained low-impact fragility fractures and had evidence of osteopaenia on both X-ray and dual energy X-ray absorptiometry (DEXA). Hyponatraemia resolved following the discontinuation of valproic acid and bone mineral density normalised on a repeat DEXA 19 months later. This case provides evidence supporting the contention that chronic hyponatraemia contributes to osteopaenia and fragility fractures and that the bone abnormalities are potentially reversible following the correction of hyponatraemia.