Age and gender as risk factors for hyponatremia and hypernatremia.
BACKGROUND
This study assesses gender and age as independent risk factors for hypo- and hypernatremia and describes the prevalence of hypo- and hypernatremia in different population groups.


METHODS
Details of all serum Na results with accompanying patient demographics for 2 years were downloaded from the laboratory database into Microsoft Access for multiple logistic regression analysis using SPSS. Female gender and age <30 years were the reference groups.


RESULTS
Data from 303577 samples on 120137 patients were available for analysis. Prevalence at initial presentation to a health care provider of Na<136, <116, >145, and >165 mmol/l were for acute hospital care patients: 28.2%, 0.49%, 1.43%, and 0.06%; ambulatory hospital care: 21%, 0.17%, 0.53%, and 0.01%; community care: 7.2%, 0.03%, 0.72%, and <0.01%. Age odds ratios rose with increasing age to 1.89 and 8.70 (Na<136 and <116 mmol/l) and 7.09 and 24.39 (Na>145 and >165 mmol/l, respectively) for age >81 years. Male gender was a mild risk factor for Na<136 mmol/l and was otherwise unimportant.


CONCLUSIONS
Hyponatremia is a common but generally mild condition while hypernatremia is uncommon. Increasing age is a strong independent risk factor for both hypo- and hypernatremia. Gender is not an important risk factor for disturbances of serum Na concentration.
Department of Pathology and Laboratory Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore. Robert_Hawkins@ttsh.com.sg
Robert C
RC
Hawkins
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D006955:Hypernatremia / Q000453:epidemiology*; D007010:Hyponatremia / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D012846:Singapore / Q000453:epidemiology; D012964:Sodium / Q000097:blood
D012964:Sodium