Hyponatremia is the most common fluid and electrolyte balance disorder1. Hyponatremia is defined as a serum sodium concentration <135 mmol/L2, and is the most common electrolyte imbalance encountered in clinical practice. It is associated with multiple poor clinical outcomes including falls, fractures, increased length of hospital stay, and mortality3. Hyponatremia itself may be responsible for the fracture4. Patients with asymptomatic hyponatremia are at higher risk of falling on account of gait disorders5. Hyponatremia occurs due to disruption of sodium and water homeostasis, normally maintained by complex multi-system physiological mechanisms3. Elderly patients with fragility fractures are particularly susceptible to hyponatremia because of their impaired physiology, multiple co-morbidities (such as hypocortisolism, hypothyroidism, hepatic cirrhosis, renal disease, and congestive heart failure), polypharmacy (e.g., antihypertensives, antidepressants and antiepileptics), hospitalization, perioperative fluid restrictions, and homeostatic stress from the fracture itself and the subsequent surgery3. These patients are also at a higher risk of the complications of hyponatremia such as brain injury, the main result of acute symptomatic hyponatremia and associated with significant morbidity and mortality6,7. Mild hyponatremia is frequently considered asymptomatic despite being strongly associated with major geriatric conditions and pathological changes. These include abnormal gait patterns, falls, fractures, cognitive impairment, bone demineralization and increased mortality8,9,10,11,12,13,14,15. Severe hyponatremia (i.e., a serum sodium concentration <125mmol/L), if unrecognized in its first stages and left untreated, has a high rate of mortality; for this reason, an accurate clinical assessment must be made, focusing on fluid status, examining the potential etiology, and conducting the appropriate investigations18. In approximately 50% of patients, chronic hyponatremia results from inappropriate antidiuretic hormone secretion19. Chronic mild hyponatremia is usually asymptomatic and is regarded as benign20. However, it is associated with a lower bone mineral content and density in nearly all regions of the hip, with more pronounced losses in the trochanteric and femoral neck regions21.Hip fractures are a most serious consequence of falls in the elderly, leading to a significant risk of morbidity and mortality22. Therefore, the aim of this study was to investigate the proportion of hyponatremia in elderly patients with hip fractures, focusing on the differences between female and male patients with extracapsular or intracapsular proximal femoral fractures. Purpose of the study It was to investigate the proportion of hyponatremia in elderly patients with hip fractures, focusing on the differences between female and male patients with extracapsular or intracapsular proximal femoral fractures

All records containing clinical and laboratory information about patients admitted to orthopaedic department of BVVS S. Nijalingappa Medical College and HSK Hospital and Research Centre, Bagalkot from 1st December 2022 – 31st November 2023 were retrieved from the hospital database. Inclusion criteria:Patients age of ≥60 years with hip fractures (extracapsular or intracapsular proximal femoral fractures). A total of 100 patients were determined from the hospital database. They were divided into 4 groups based on sex and type of fracture (extracapsular or intracapsular). This division was made to evaluate the link between hyponatremia and different types of hip fractures. Serum sodium concentrations were retrieved from the records and proportion of hyponatremia on admission to hospital was determined

Of the 100 patients, there were more males ( n = 54, 54%) than females ( n = 46, 46%), with a ratio of 1.2: 1. In both male and female patients,there were more extracapsular proximal femoral fractures,30/54 (55%) and 32/46 (69%), respectively than intracapsular proximal femoral fractures, 24/54 (44%) and 14/46 (30%),respectively.Overall, the proportion of hyponatremia in the total population was 22% (22/100). The proportion of hyponatremia was 23% (7/30) for male patients with extracapsular proximal femoral fracture, 16% (4/24) for male patients with intracapsular proximal femoral, 15% (5/32) for female patients with extracapsular proximal femoral fracture and 42% (6/14) for female patients with intracapsular proximal femoral fracture. 13 out of the 22 patients were found to be diabetic.

In this study, the proportion of hyponatremia in patients with proximal femoral fractures was high. The proportion of hyponatremia was 23% for male patients with extracapsular proximal femoral fracture, 16% for male patients with intracapsular proximal femoral fracture, 15% for female patients with extracapsular proximal femoral fracture, and 42% for female patients with extracapsular proximal femoral fracture. The mean 22% prevalence of hyponatremia in the total population was lower than the 26% reported by Cumming et al23. This difference could be due to different study population. It is noteworthy that the study population in Cumming et al. was not restricted to femoral fractures, and included all fractures that are caused in the elderly due to fragility. Mild chronic hyponatremia should not be viewed as a benign condition20 because it is caused by multiple comorbidities or pharmacologic treatments (e.g., antihypertensives, antidepressants, and antiepileptics), and can lead to a majority of the pathologies and rarely cause mortality,both within and outside the hospital set up3,6,7,24,25,26. Even mild hyponatremia in the elderly should be considered a risk factor for falls11. The treatment of mild hyponatremia is still up for debate, especially in the elderly. Rapid correction of Chronic hyponatremia is not advised beacuse if corrected rapidly, it may be associated with severe complications, especially serious neurologic injury in patients undergoing fluid restriction27. The serial assessment of serum sodium concentration is a simple, inexpensive, and rapid biochemical test. It is easy and advisable for all clinicians to check for hyponatremia in all elderly patients with risk factors of hyponatremia and plan an effective clinical management28. Limitations : The limitations of this study were : 1. The lack of data on the etiology of hyponatremia in each patient. 2. Only diabetic status of the individuals was taken into account and other co-morbidties were not taken into considerations 3. Detailed history of long standing treatment or chronic drug usage not present 4. No data on presence or absence of other pre existing conditions or end stage diseases

There was high prevalence (22%) of hyponatremia in elderly patients with hip fractures. Serum sodium concentrations should be routinely assessed in elderly patients with hip fractures to prevent occurrence of Hyponatremia.

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