Table 1.

Serum sodium concentration in patients with femoral neck fracture and in a control population of unselected outpatients.

Total population	Controls	Patients	P
n	700	543
Age (years)	66 (52–77)	84 (77–89)	<0.001
M/F	407/293	387/156	<0.001
Sodium (mmol/L)	139 (137–141)	138 (136–140)	<0.001
(i) Hyponatremia	73/700 (10.4%)	106/543 (19.5%)	<0.001
(ii) Severe hyponatremia	0/700 (0%)	6/543 (1.1%)	0.009
>65 years	Controls	Patients	P
n	380	491
Age (years)	76 (71–83)	85 (80–90)	<0.001
M/F	223/157	360/131	<0.001
Sodium (mmol/L)	139 (137–141)	138 (136–140)	<0.001
(i) Hyponatremia	45/380 (11.8%)	102/491 (20.8%)	<0.001
(ii) Severe hyponatremia	0/380 (0%)	6/491 (1.2%)	0.040