Hyponatremia, a risk factor for osteoporosis and fractures in women

Mild Hyponatremia Is Not Associated With Degradation of Trabecular Bone Microarchitecture Despite Bone Mass Loss

CONTEXT

Hyponatremia is associated with increased risk of osteoporosis and fractures. The impact of hyponatremia on noninvasive indices of bone quality, however, is unknown.

OBJECTIVE

To evaluate whether trabecular bone microarchitecture, assessed noninvasively by trabecular bone score (TBS), is altered in patients with hyponatremia.

METHODS

We conducted a cross-sectional analysis of the population-based 2005-2008 cycles of the National Health and Nutrition Examination Survey, in which TBS measurement was performed. The main outcome measures were TBS values and bone mineral density (BMD) T-scores at the lumbar spine, total hip and femoral neck.

RESULTS

A total of 4204 subjects aged 50 years or older were included (4041 normonatremic, 163 hyponatremic-90.8% with mild hyponatremia). Univariate analyses did not show any difference in TBS between patients with and without hyponatremia (1.308 ± 0.145 vs 1.311 ± 0.141, P = .806). Hyponatremic subjects had lower BMD T-score at total hip (-0.70 ± 1.46 vs -0.13 ± 1.32, P < .001) and femoral neck (-1.11 ± 1.26 vs -0.72 ± 1.14, P = .004), while no difference was observed at lumbar spine (-0.27 ± 1.63 vs -0.31 ± 1.51, P = .772). After adjustment for relevant confounders, hyponatremia was confirmed as an independent predictor of lower BMD T-score at the total hip (β = -0.20, 95% confidence interval [CI]: [-0.39, -0.02], P = .029), while the significance was lost at the femoral neck (P = .308). Again, no association between hyponatremia and lumbar spine BMD (P = .236) or TBS (P = .346) was observed.

CONCLUSION

Hyponatremia, at least in mild forms, is not associated with a degradation of trabecular microarchitecture, assessed noninvasively by TBS. An independent association between hyponatremia and loss of bone mass is confirmed, particularly at the total hip.

The nonpathogenic role of hyponatremia in the onset of osteoporosis: A Mendelian randomization study

The relationship between hyponatremia and osteoporosis is controversial, and it remains unclear if there is a causal link between the two. This study employed a 2-sample Mendelian randomization (MR) analysis to investigate the potential causal relationship between hyponatremia and osteoporosis. The instrumental variables were derived from genome-wide association studies conducted in European populations. These included hyponatremia (n = 465,348) as the exposure factor, with genetic summary data for bone mineral density (BMD) at the forearm (n = 8134), femoral neck (n = 32,735), lumbar spine (n = 28,498), and heel (n = 265,627) as outcomes. The inverse variance weighted method did not identify any causal effect of hyponatremia on BMD. Additionally, other methods, such as MR-Egger, weighted median, simple mode, and weighted mode, also did not show evidence of a causal relationship between hyponatremia and BMD. Pleiotropy and heterogeneity analyses indicated that the MR findings were robust. There is no significant causal relationship between hyponatremia and osteoporosis. The previously observed associations may be due to confounding factors. It is unlikely that hyponatremia is a causal factor for osteoporosis.

Regional disparities, age-related changes and sex-related differences in knee osteoarthritis

BACKGROUND

The objective of the study is to analyse the regions, age and sex differences in the incidence of knee osteoarthritis (KOA).

METHODS

Data were extracted from the global burden of diseases (GBD) 2019 study, including incidence, years lived with disability (YLD), disability-adjusted life-years (DALYs) and risk factors. Estimated annual percentage changes (EAPCs) were calculated to quantify the temporal trends in age standardized rate (ASR) of KOA. Paired t-test, paired Wilcoxon signed-rank test and spearman correlation were performed to analyze the association of sex disparity in KOA and socio-demographic index (SDI).

RESULTS

There were significant regional differences in the incidence of knee osteoarthritis. In 2019, South Korea had the highest incidence of knee osteoarthritis (474.85,95%UI:413.34-539.64) and Thailand had the highest increase in incidence of knee osteoarthritis (EAPC = 0.56, 95%CI = 0.54-0.58). Notably, higher incidence, YLD and DALYs of knee osteoarthritis were associated with areas with a high socio-demographic index (r = 0.336, p < 0.001; r = 0.324, p < 0.001; r = 0.324, p < 0.001). In terms of age differences, the greatest increase in the incidence of knee osteoarthritis was between the 35-39 and 40-44 age groups. (EAPC = 0.52, 95%CI = 0.40-0.63; 0.47, 95%CI = 0.36-0.58). In addition, there were significant sex differences in the disease burden of knee osteoarthritis (P < 0.001).

CONCLUSIONS

The incidence of knee osteoarthritis is significantly different with regions, age and sex.

Application of neural network and nomogram for the prediction of risk factors for bone mineral density abnormalities: A cross-sectional NHANES-based survey

Background

The risk of bone mineral density abnormalities is inconsistent between eastern and western regions owing to differences in ethnicity and dietary habits. A diet comprising carbohydrates and dietary fiber is not the common daily diet of the American population. Thus far, no studies have assessed the risk of bone mineral density abnormalities in the American population, and no predictive model has considered the intake of carbohydrates, dietary fiber, and coffee, as well as levels of various electrolytes for assessing bone mineral density abnormalities, especially in the elderly. This study conducted a neural network analysis and established a predictive nomogram considering an unusual diet to determine risk factors for bone mineral density abnormalities in the American population, mainly to provide a reference for the prevention and treatment of related bone mineral density abnormalities.

Methods

Overall, 9871 patients who had complete data were selected from the National Health and Nutrition Examination Survey database during 2017-2020 as the research object, and patients' general clinical characteristics were compared. Neural networks and nomograms were analyzed to screen for and quantify risk factors for bone mineral density abnormalities. Finally, the receiver operating characteristic (ROC) curve, calibration curve, decision curve analysis (DCA), and community indifference curve (CIC) were constructed to comprehensively verify the accuracy, differential ability, and clinical practicability of the neural network and nomogram.

Results

The important risk factors for bone mineral density abnormalities were caffeine intake, carbohydrate consumption, body mass index (BMI), height, blood sodium, blood calcium, blood phosphorus, blood potassium, dietary fiber, vitamin D, participant age, weight, race, family history, and sex. The nomogram revealed that caffeine intake, carbohydrate consumption, blood potassium, and age were positively correlated with bone mineral density abnormalities, whereas BMI, height, blood phosphate, dietary fiber, and blood sodium were negatively correlated with bone mineral density abnormalities. Women were more prone to these abnormalities than men. The area under the ROC curve values of the neural network and nomogram were 85.8 % and 77.7 %, respectively. The Youden index was 58.04 % and 41.87 %, respectively. The detection sensitivity was 75.73 % and 65.06 %, respectively, and the specificity was 82.31 % and 76.81 %, respectively. Calibration curves of the neural network and nomogram showed better discrimination ability from the standard curve (P > 0.05). DCA and CIC analyses showed that the application of the neural network and nomogram to explore risk factors for bone mineral density abnormalities had certain clinical practicability, and the overall predictive effect of the model was good.

Conclusion

The outcomes of the neural network and nomogram analyses suggested that diet structure and electrolyte changes are important significant risk factors for bone mineral density abnormalities, especially with increasing carbohydrate and caffeine intake and decreasing dietary fiber intake. The established model can also provide a reference for future risk prediction.

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.

Hyponatremia and aging-related diseases: key player or innocent bystander? A systematic review

BACKGROUND

Hyponatremia is frequent in older age; whether it is a key player, a surrogate marker, or an innocent bystander in age-related diseases is still unclear.

OBJECTIVE

To understand the role of hyponatremia in falls, osteoporosis, fractures, and cognitive impairment in old patients.

METHOD

Eligibility criteria for study inclusions were: written in English, peer-reviewed observational and intervention studies, clinical trial, prospective and retrospective controlled cohort studies, and case-controlled studies without limitations regarding the date of publication.

INFORMATION SOURCES

Protocol available on the International Prospective Register of Systematic Reviews (PROSPERO, CRD42021218389). MEDLINE, Embase, and PsycINFO were searched. Final search done on August 8, 2021. Risk-of-bias assessment: Risk-of-Bias Assessment tool for Non-randomized Studies (RoBANS) and the Bradford Hill's criteria for causality.

RESULTS

Includes studies: One-hundred thirty-five articles retained for the revision. Synthesis of results - Falls: Eleven studies were included. Strong association between hyponatremia and falls in all the studies was found. Osteoporosis and fractures: nineteen articles were included. The association between hyponatremia and osteoporosis is unclear. Cognitive impairment: Five articles were included. No association between hyponatremia and cognitive impairment was found.

DISCUSSION

Interpretation: Falls, osteoporosis, and fractures are multifactorial. Hyponatremia is not temporally related with the outcomes; we suggest that hyponatremia may be regarded as a marker of unhealthy aging and a confounder instead of a causal factor or an innocent bystander for falls and fractures. Concerning cognitive impairment, there are no evidence supporting a real role of hyponatremia to be regarded as an innocent bystander in neurodegeneration.

Preoperative Malnutrition and Metabolic Markers May Predict Periprosthetic Fractures in Total Hip Arthroplasty

Background

Periprosthetic fractures are a devastating complication of total hip arthroplasty (THA) and are associated with significantly higher mortality rates in the postoperative period. Given the strain that periprosthetic fractures place on the patient as well as the healthcare system, identifying and optimizing medical comorbidities is essential in reducing complications and improving outcomes.

Methods

All THA with primary indications of osteoarthritis from 2007 to 2020 were queried from the National Surgical Quality Improvement Program database. Demographic data, preoperative laboratory values, medical comorbidities, hospital course, and acute complications were collected and compared between patients with and without readmission for a periprosthetic fracture. A multivariate logistic regression analysis was performed to determine associated independent risk factors for periprosthetic fractures after index THA.

Results

The analysis included 275,107 patients, of which 2539 patients were readmitted for periprosthetic fractures. Patients with postoperative fractures were more likely to be older (>65 years), females, BMI >40, and increased medical comorbidities. Preoperative hypoalbuminemia, hyponatremia, and abnormal estimated glomerular filtration rates were independent risk factors for sustaining a periprosthetic fracture and readmission within 30 days. Modifiable patient-related factors of concurrent smoking and chronic steroid use at the time of index THA were also independent risk factors for periprosthetic fractures. Inpatient metrics of longer length of stay, operative time, and discharge to rehab predicted postarthroplasty fracture risk. Readmitted fracture patients subsequently had increased risks of developing a surgical site infection, urinary tract infection, and requiring blood transfusions.

Conclusions

Patients with hypoalbuminemia, hyponatremia, and abnormal estimated glomerular filtration rate are at increased risk for sustaining periprosthetic fractures after THA. Preoperative optimization with close monitoring of metabolic markers and modifiable risk factors may help not only prevent acute periprosthetic fractures but also associated infection and bleeding risk with fracture readmission.

A Survey Study on the Status of Somatic Symptoms in Young and Middle-Aged Patients with Mental Illness during Long-Term Hospitalization

Psychiatric disorders include severe psychiatric disorders and those in general with some psychiatric disorders having a clear etiology or in which a significant psychiatric predisposing factor is present. Whereas, psychiatric disorders precisely refer to those characterized by mild depression and mild anxiety and appear to affect a large number of people in any community. It has been reported that the disease is highly prevalent and has a huge impact on the individual, family, and community levels, resulting in a heavy burden on the healthcare system of a country. To explore the status of somatic symptoms in young and middle-aged psychiatric patients during long-term hospitalization, a total of 114 young and middle-aged psychiatric patients with prolonged hospitalization (more than 5 years) were included. Data information of the hospitalized patients was recorded, including preadmission somatic symptoms, electrocardiogram (ECG), echocardiogram, abdominal ultrasound, and blood tests. In addition, a homemade questionnaire was administered, and general information about the patients was also collected, including gender, age, current medication use, and duration of medication use. Correlations between cardiometabolic disease, osteoporosis, and long-term oral antipsychotic medication were analyzed in these young and middle-aged patients. The prevalence of comorbid somatic symptoms was 77.2%, and concomitant disorders included mainly cardiometabolic disorders, osteoporosis, pulmonary infections, cerebrovascular disorders, digestive disorders, fractures, and skin conditions. The incidence of somatic symptoms caused by long-term use of antipsychotic drugs was about 88.6%, and the incidence of concomitant somatic symptoms was higher in young and middle-aged psychiatric patients who were hospitalized for a long time. The current study observed a high prevalence of somatic symptoms in young and middle-aged patients with long-term inpatient psychiatric illness. Endocrine and metabolic disorders, particularly dyslipidemia, may trigger a range of deleterious effects. In addition to this, there is a high incidence of osteoporosis. Special attention should be paid to the side effects of antipsychotic drugs, and appropriate measures are needed to make early diagnosis and provide early treatment to reduce the occurrence of cardiometabolic diseases and osteoporosis.

Spine Surgery and Preoperative Hemoglobin, Hematocrit, and Hemoglobin A1c: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Synthesize previous studies evaluating clinical utility of preoperative Hb/Hct and HbA1c in patients undergoing common spinal procedures: anterior cervical discectomy and fusion (ACDF), posterior cervical fusion (PCF), posterior lumbar fusion (PLF), and lumbar decompression (LD).

METHODS

We queried PubMed, Embase, Cochrane Library, and Web of Science for literature on preoperative Hb/Hct and HbA1c and post-operative outcomes in adult patients undergoing ACDF, PCF, PLF, or LD surgeries.

RESULTS

Total of 4,307 publications were assessed. Twenty-one articles met inclusion criteria.

PCF AND ACDF

Decreased preoperative Hb/Hct were significant predictors of increased postoperative morbidity, including return to operating room, pulmonary complications, transfusions, and increased length of stay (LOS). For increased HbA1c, there was significant increase in risk of postoperative infection and cost of hospital stay.

PLF

Decreased Hb/Hct was reported to be associated with increased risk of postoperative cardiac events, blood transfusion, and increased LOS. Elevated HbA1c was associated with increased risk of infection as well as higher visual analogue scores (VAS) and Oswestry disability index (ODI) scores.

LD

LOS and total episode of care cost were increased in patients with preoperative HbA1c elevation.

CONCLUSION

In adult patients undergoing spine surgery, preoperative Hb/Hct are clinically useful predictors for postoperative complications, transfusion rates, and LOS, and HbA1c is predictive for postoperative infection and functional outcomes. Using Hct values <35-38% and HbA1c >6.5%-6.9% for identifying patients at higher risk of postoperative complications is most supported by the literature. We recommend obtaining these labs as part of routine pre-operative risk stratification.

LEVEL OF EVIDENCE

III.

Urine and Serum Electrolytes and Biochemical Values Associated with Osteoporosis in Premenopausal and Postmenopausal Women: A Longitudinal and Cross-Sectional Study Using Korean Genome and Epidemiology Study (KoGES) Cohort

Osteoporosis is a major public health concern, especially in women. This study aims to identify early biomarkers from biochemical measurements of serum and urine for recognizing the development of osteoporosis and osteopenia in premenopausal and postmenopausal women. From the Korean Genome and Epidemiology Study (KoGES) cohort, longitudinal study participants with normal bone density were enrolled and assessed for the association of baseline clinical and biochemical factors with osteoporosis development over 4 years. In addition, a cross-sectional study between normal bone density and osteopenia/osteoporosis was conducted to validate the risk factors found in the longitudinal cohort. Of the 5272 female participants in the KoGES cohort, 813 women (501 premenopausal and 312 menopausal) who had normal bone density at baseline were included in the longitudinal study. During the 4 years of follow-up, 64 patients developed osteoporosis and 354 developed osteopenia. In a multivariate logistic regression analysis, serum calcium and urine uric acid levels were significantly associated with elevated osteoporosis risk in premenopausal and postmenopausal women, respectively (risk of osteoporosis by serum calcium levels in premenopausal women: 4.03 (1.09–14.93), p = 0.037; risk of osteoporosis by urine uric acid levels in postmenopausal women: 24.08 (1.79–323.69), p = 0.016). For the cross-sectional study, serum and urine parameters were compared between women with osteopenia or osteoporosis at baseline and those with normal bone density. Urine uric acid levels were found to be significantly higher in both premenopausal and postmenopausal women with bone loss than in women with normal bone density (p < 0.001 and p = 0.004, respectively). Uric acid level in urine may be an early marker for the development of osteoporosis in women, especially after menopause.

Chronic prolonged hyponatremia and risk of hip fracture in elderly patients with chronic kidney disease

BACKGROUND

Chronic prolonged hyponatremia (CPH) is a risk factor for hip fracture in the general population. Whether CPH increases hip fracture risk in chronic kidney disease (CKD) patients is unknown.

METHODS

Case-control study in patients over 60 years of age with stage 3 or greater CKD. Patients who had a hip fracture were referred to as cases (n = 1236) and controls had no hip fracture (n = 4515). Patients were classified as having CPH if serum sodium was <135 mEq/L on at least two occasions separated by a minimum of 90 days prior to the diagnosis of hip fracture (cases) or at any time during the study period (controls). Conditional logistic regression models were used to test the association between CPH and hip fracture. Analyses were conducted for patients with and without osteoporosis and falls and for patients with age >70 years versus ≤70 years.

RESULTS

CPH was present in 21% of cases and 10% of controls (p < 0.001; sodium level: 131-134 mEq/L). In univariate logistic regression analysis, CPH was associated with higher odds of hip fracture (odds ratio [OR] 2.44, (95% [CI] 2.07-2.89). In a multivariate model adjusted for comorbidities, medications and laboratory parameters CPH association with higher odds of Hip fracture was attenuated but remained significant (OR 1.36, 95% CI 1.04-1.78). The association between CPH and risk of hip fracture was consistent in patients with or without osteoporosis and falls and across the age strata.

CONCLUSION

Chronic prolonged hyponatremia is a risk factor for hip fracture in CKD patients older than 60 years of age.

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

Objective: Hyponatremia decreases bone mineral density and is a major risk factor for fragility fractures. Objectives of our systematic review and meta-analysis were to analyze the overall effects of hyponatremia on bone fractures, osteoporosis, and mortality. Methods: We extracted data from Medline, Cochrane Central, and EMBASE 1960-2017 and conference abstracts from 2007-2017. We included studies with data on serum sodium, fractures, bone density, or diagnoses of osteoporosis. Studies were independently reviewed by two authors and assessed for bias using the Newcastle-Ottawa scale. Random effect models meta-analysis was used when at least three studies reported the same outcome measures. We reported summary odds ratios (ORs) and 95% confidence intervals (CIs). Results: We included 26 studies for qualitative analysis. Fifteen studies were included in the meta-analysis to evaluate the effects of hyponatremia on fractures, four studies for bone mineral density changes, and six for mortality. Hyponatremia increased the odds of fractures at all sites (summary OR, 2.34 [95% CI, 1.86, 2.96]. There was an increase in the odds of osteoporosis (summary OR, 2.67 [95% CI, 2.07, 3.43]). Mortality risk among the included studies remained high (summary OR, 1.31 [95% CI, 1.16, 1.47]). Conclusion: Our meta-analysis confirms a statistically significant association of hyponatremia with bone fractures and osteoporosis along with higher mortality. Long-term prospective studies evaluating the impact of correcting hyponatremia on bone health, fractures, and mortality are required. Abbreviations: AVP = arginine vasopressin; CI = confidence interval; CKD = chronic kidney disease; OR = odds ratio; SIADH = syndrome of inappropriate antidiuretic hormone.

Fracture risk in women with type II diabetes. Results from a historical cohort with fracture follow-up

PURPOSE

To examine the independent association between type II diabetes and fracture risk in a population of predominantly postmenopausal women referred to a specialist clinic for osteoporosis evaluation.

METHODS

Type II diabetes associated fracture risk were evaluated among to 229 patients with type II diabetes in a cohort of 6285 women followed on average (until major osteoporotic fracture (MOF), death or end of study) for 5.8 years. Information of fracture risk factors was obtained from a clinical database and from national registries.

RESULTS

An elevated fracture risk was present. Prevalent fractures (43.7 vs. 33.2%, p = 0.0010) and prevalent MOF (26.2 vs. 20.5% p = 0.038) were more common among patients with type II diabetes. The unadjusted incident fracture risk was increased with a higher relative risk of 42%. An elevated MOF hazard ratio was present (HR = 1.726, p = 0.0006). Adjustment for prevalent osteoporosis and other possible confounders did not change this finding (HR = 1.558, p = 0.0207).

CONCLUSIONS

An association between type II diabetes and an increased risk of MOF primarily driven by an increased hip fracture risk was documented. This finding was independent of the presence of osteoporosis. Clinicians need to be aware of and adjust for these findings when evaluating patients with diabetes. Additional research examining pathophysiological mechanisms are needed.

Hyponatremia and fractures: should hyponatremia be further studied as a potential biochemical risk factor to be included in FRAX algorithms?

The Fracture Risk Assessment Tool (FRAX®) was developed by the WHO Collaborating Centre for metabolic bone diseases to evaluate fracture risk of patients. It is based on patient models that integrate the risk associated with clinical variables and bone mineral density (BMD) at the femoral neck. The clinical risk factors included in FRAX were chosen to include only well-established and independent variables related to skeletal fracture risk. The FRAX tool has acquired worldwide acceptance despite having several limitations. FRAX models have not included biochemical derangements in estimation of fracture risk due to the lack of validation in large prospective studies. Recently, there has been an increasing number of studies showing a relationship between hyponatremia and the occurrence of fractures. Hyponatremia is the most frequent electrolyte abnormality measured in the clinic, and serum sodium concentration is a very reproducible, affordable, and readily obtainable measurement. Thus, we think that hyponatremia should be further studied as a biochemical risk factor for skeletal fractures prediction, particularly those at the hip which carries the greatest morbidity and mortality. To achieve this will require the collection of large patient cohorts from diverse geographical locations that include a measure of serum sodium in addition to the other FRAX variables in large numbers, in both sexes, over a wide age range and with wide geographical representation. It would also require the inclusion of data on duration and severity of hyponatremia. Information will be required both on the risk of fracture associated with the occurrence and length of exposure to hyponatremia and to the relationship with the other risk variables included in FRAX and also the independent effect on the occurrence of death which is increased by hyponatremia.

Hyponatremia and bone disease

Hip fractures represent a serious health risk in the elderly, causing substantial morbidity and mortality. There is now a considerable volume of literature suggesting that chronic hyponatremia increases the adjusted odds ratio (OR) for both falls and fractures in the elderly. Hyponatremia appears to contribute to falls and fractures by two mechanisms. First, it produces mild cognitive impairment, resulting in unsteady gait and falls; this is probably due to the loss of glutamate (a neurotransmitter involved in gait function) as an osmolyte during brain adaptation to chronic hyponatremia. Second, hyponatremia directly contributes to osteoporosis and increased bone fragility by inducing increased bone resorption to mobilize sodium stores in bone. Low extracellular sodium directly stimulates osteoclastogenesis and bone resorptive activity through decreased cellular uptake of ascorbic acid and the induction of oxidative stress; these effects occur in a sodium level-dependent manner. Hyponatremic patients have elevated circulating arginine-vasopressin (AVP) levels, and AVP acting on two receptors expressed in osteoblasts and osteoclasts, Avpr1α and Avpr2, can increase bone resorption and decrease osteoblastogenesis. Should we be screening for low serum sodium in patients with osteoporosis or assessing bone mineral density (BMD) in patients with hyponatremia? The answers to these questions have not been established. Definitive answers will require randomized controlled studies that allocate elderly individuals with mild hyponatremia to receive either active treatment or no treatment for hyponatremia, to determine whether correction of hyponatremia prevents gait disturbances and changes in BMD, thereby reducing the risk of fractures. Until such studies are conducted, physicians caring for elderly patients must be aware of the association between hyponatremia and bone disorders. As serum sodium is a readily available, simple, and affordable biochemical measurement, clinicians should look for hyponatremia in elderly patients, especially in those receiving medications that can cause hyponatremia. Furthermore, elderly patients with an unsteady gait and/or confusion should be evaluated for the presence of mild hyponatremia, and if present, treatment should be initiated. Finally, elderly patients presenting with an orthopedic injury should have serum sodium checked and hyponatremia corrected, if present.

Physiopathology, clinical diagnosis, and treatment of hyponatremia

Hyponatremia is the commonest electrolyte disorder encountered in clinical practice. It develops when the mechanisms regulating water and electrolyte handling are impaired, which in many instances occur in the setting of concurrent diseases such as heart failure, liver failure, renal failure etc… Hyponatremia as an electrolyte disorder has several specificities: when profound it can be quickly fatal and when moderate it carries a high risk of mortality and morbidity, but at the same time incorrect treatment of profound hyponatremia can lead to debilitating neurological disease and it remains unclear if treatment of moderate hyponatremia is associated with a decrease in mortality and morbidity. A proper diagnosis is the keystone for an adequate treatment for hyponatremia and in the last few years many diagnosis algorithms have been developed to aid in the evaluation of the hyponatremic patient. Also because of the availability of vasopressin receptor antagonists and the advances made in the research regarding complications associated with hyponatremia treatment, new treatment recommendations have been published recently by several panels. This review will discuss the physiopathology, epidemiology, and clinical manifestations of hyponatremia and also the diagnosis and the treatment of this disorder with special emphasis on the complication from overly rapid correction of hyponatremia.

Time trends in osteoporosis risk factor profiles: a comparative analysis of risk factors, comorbidities, and medications over twelve years

The aim of this article was to identify prevalent osteoporosis risk factors, medications and comorbidities associated with bone mineral density (BMD). Furthermore to evaluate changes in risk factor profiles over 12 years. 6285 women consecutively referred to an osteoporosis specialist clinic were included. Information of potential risk factors was obtained by questionnaire and clinical examination. Additional information on medication use, comorbidities and fractures were obtained from national registries. An association (<0.05) between well-known risk factors negatively influencing bone health was established in a real-life setting. The prevalence of osteoporosis and proportion of patient's having comorbidity's associated with osteoporosis were increasing during the inclusion period (start 23.8 %, end 29.7 %). Increasing age (OR = 1.05), current smoking (OR = 1.18), estrogen deficiency (OR = 1.7), hyperthyroidism (OR = 1.5), previous major osteoporotic fracture (OR = 1.7), former osteoporosis treatment (OR = 3.5), higher BMI (OR = 0.87), use of calcium supplementation (OR = 1.2), high exercise level (OR = 0.7), and use of thiazide diuretics (OR = 0.7) were identified as predictors of osteoporosis by DXA. Rheumatoid arthritis (OR = 2.4) and chronic pulmonary disease (OR = 1.5) was associated with site-specific osteoporosis by DXA at the total hip. Current use of loop diuretics (OR = 1.7) and glucocorticoid use (OR = 1.04-1.06) were associated with both total hip and femoral neck T-score <-2.5. Our data confirms an independent negative association with BMD of many established risk factors, certain comorbidities, and medications. Exercise level, use of loop diuretics, and prevalent chronic pulmonary disease, risk factors not included in fracture risk calculators were associated with osteoporosis by DXA. Time trends indicate risk profile is dynamic, with increasing focus on secondary osteoporosis.