Mild hyponatremia and risk of fracture in the ambulatory elderly.
BACKGROUND
Mild hyponatremia is the commonest electrolyte imbalance in the older population and has been shown to be associated with gait and attention deficits resulting in higher frequency of falls. The association of mild hyponatremia and bone fracture is still unknown.


OBJECTIVE
To determine if mild hyponatremia is associated with increased risk of bone fracture in ambulatory elderly.


METHODS
Case control study of 513 cases of bone fracture after incidental fall in ambulatory patients aged 65 or more in general university hospital. Controls were age and sex matched randomly selected ambulatory patients without history of bone fracture.


METHODS
Odds ratio (OR) of bone fracture after incidental fall associated with presence of hyponatremia.


RESULTS
Prevalence of hyponatremia (serum sodium <135 mEq/l,) in patients with bone fracture and in controls patient was, respectively, 13.06% and 3.90%. Hyponatremia was mild and asymptomatic in all patients (mean serum sodium 131 mEq/l) and was found to be associated with bone fracture after incidental fall in ambulatory elderly (unadjusted OR: 3.47, 95% CI: 2.09-5.79, and adjusted OR: 4.16 95% CI: 2.24-7.71). Hyponatremia was either drug induced (36% diuretics, 17% selective serotonin reuptake inhibitors) or resulted from idiopathic syndrome of inappropriate antidiuretic hormone secretion (37%). Hyponatremia was associated with 9.20% of all bone fractures.


CONCLUSIONS
Mild asymptomatic hyponatremia is associated with bone fracture in ambulatory elderly and avoiding iatrogenic hyponatremia or treating hyponatremia may decrease the number of bone fractures in this population.
Gankam Kengne
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F
Service de Médecine Interne Générale, Hôpital Erasme, 808 Route de Lennik, 1070 Bruxelles, Belgium. fgankamk@ulb.ac.be
Andres
C
C
Sattar
L
L
Melot
C
C
Decaux
G
G
D000058:Accidental Falls / Q000706:statistics & numerical data; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D050723:Fractures, Bone / Q000209:etiology* / Q000517:prevention & control; D006801:Humans; D007010:Hyponatremia / Q000150:complications / Q000453:epidemiology*; D007177:Inappropriate ADH Syndrome / Q000453:epidemiology*; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D012307:Risk Factors