Falls and fractures with hyponatremia in the elderly
Hyponatremia may be an independent risk factor for falls and fractures in the elderly population.1
Bone fractures occur more often in elderly patients with hyponatremia than in elderly patients without hyponatremia2,3
The reported prevalence of hyponatremia varies, but tends to be significantly higher in the patients with bone fractures compared to those without bone fractures, suggesting that bone fractures in patients with hyponatremia may be attributed to hyponatremia.2,3
Reported prevalences of hyponatremia in patients with bone fractures versus those without fractures:
Secondary analysis of a retrospective study that involved elderly females (mean age: 61 years; N=1,408) who had a bone mineral density measurement done at a university hospital2:
- Analyzed the prevalence of hyponatremia (serum [Na+] <135 mEq/L) in females with and without bone fractures
- The prevalence of hyponatremia in females with fractures (n=254) was significantly greater (P<0.001) than females without fractures (n=1,154)
- Females with fractures: 8.7%
- Females without fractures: 3.2%
Retrospective case-control analysis of serum sodium concentration in hospitalized elderly patients aged ≥65 years3:
- The prevalence of hyponatremia (serum [Na+] <135 mEq/L) was analyzed in patients with a diagnosis of bone fracture secondary to a fall, and in randomly selected sex- and age-matched control patients with no history of bone fractures
- The prevalence of hyponatremia was significantly (P<0.0001) greater in patients with bone fractures (n=513) compared to controls with no history of bone fracture (n=513)
- Bone fracture patients: 13.1%
- Controls: 3.9%
- Bone fracture was attributed to hyponatremia alone in as much as 72.5% of the cases of hyponatremia (95% CI: 57.82-87.21)
Hyponatremia is associated with increased falls in the elderly population4
One study has found that a significantly greater number of falls occur in elderly patients with hyponatremia compared to elderly patients without hyponatremia. This may be due to gait and attention disorders, which have been found in elderly patients with hyponatremia.4
Prevalence of falls in elderly patients with hyponatremia versus those with normonatremia
Case-control study of hospitalized patients4:
- Compared the prevalence of falls in patients with chronic hyponatremia (serum [Na+] 115-132 mEq/L, n=122) to age- and sex-matched controls (n=244)
- The prevalence of falls was significantly (P<0.001) greater in the patients with hyponatremia compared to the patients without hyponatremia
- Hyponatremia: 21.3%
- Normonatremia: 5.3%
- Patients with hyponatremia had gait disturbances and attention deficits despite being considered clinically asymptomatic
Hyponatremia may contribute to osteoporosis and increased bone frangibility1,5
The increased risk of bone fracture in elderly patients with hyponatremia may not only be due to the increased risk of falls, but also due to the effects hyponatremia has on bone mineral density and the increased risks for osteoporosis.1,5
Analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III)5:
- Analyzed association of serum sodium concentration and femoral neck bone mineral density in adults aged ≥50 years with and without hyponatremia
- Significant positive linear association between serum sodium concentration and femoral neck bone mineral density participants with hyponatremia (P<0.01) that was not seen in the normonatremic participants (P=0.99)
- The risk for developing osteoporosis in the femoral neck was 2.87 times greater (95% CI –1.41 to –5.81; P=0.003) in participants with mild hyponatremia (mean serum [Na+]: 133.0±0.2 mEq/L) compared to those participants without hyponatremia (mean serum [Na+]: 141.4±0.1 mEq/L)
- Ayus JC, Negri AL, Kalantar-Zadeh Kamyar, Moritz ML. Is chronic hyponatremia a novel risk factor for hip fracture in the elderly? Nephrol Dial Transplant. 2012;27:3725-3731. doi:10.1093/ndt/gfs412.
- Kinsella S, Moran S, Sullivan MO, Molloy MG, Eustace JA. Hyponatremia independent of osteoporosis is associated with fracture occurrence. Clin J Am Soc Nephrol. 2010;5(2):275-280. doi:10.2215/CJN.06120809.
- Gankam Kengne F, Andres C, Sattar L, Melot S, Decaux G. Mild hyponatremia and risk of fracture in the ambulatory elderly. QJM. 2008;101(7):583-588. doi:10:1093/qjmed/hcn061.
- Renneboog B, Musch W, Vandemergel X, Manto MU, Decaux G. Mild chronic hyponatremia is associated with falls, unsteadiness, and attention deficits. Am J Med. 2006;119(1):71.e1-71.e8.
- Verbalis JG, Barsony J, Sugimura Y, et al. Hyponatremia-induced osteoporosis. J Bone Miner Res. 2010;25(3):554-563. doi:10.1359/jbmr.090827.