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Novel risk factors for hospital‐acquired hyponatraemia: a matched case–control study
Author(s) -
Beukhof Carolien M.,
Hoorn Ewout J.,
Lindemans Jan,
Zietse Robert
Publication year - 2007
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2007.02741.x
Subject(s) - medicine , odds ratio , confidence interval , diabetes mellitus , gastroenterology , logistic regression , insulin , case control study , antibiotics , c reactive protein , endocrinology , microbiology and biotechnology , inflammation , biology
Summary Background Hospital‐acquired hyponatraemia is a common and potentially serious condition. Risk factors for hospital‐acquired hyponatraemia have not been studied in a controlled fashion. Methods From 1501 patients in whom serum sodium (S Na ) was determined, 50 cases with hospital‐acquired hyponatraemia (in‐hospital decrease in S Na ≥ 7 mmol/l to < 136 mmol/l) were identified. They were matched by age, gender and department to 69 normonatraemic controls. Results In the 50 cases, S Na fell from 141 ± 2 to 130 ± 4 mmol/l, while controls remained normonatraemic. During the development of hyponatraemia, C‐reactive protein (CRP) increased in cases (median from 23 to 146 mg/l), whereas it decreased in controls (median from 31 to 24 mg/l, P = 0·008). Additional factors associated with hospital‐acquired hyponatraemia included diabetes mellitus (16/50 vs. 10/69, P = 0·009) and the use of insulin (12/50 vs. 4/69, P = 0·007), antibiotics (41/50 vs. 38/69, P = 0·006) and opioids (32/50 vs. 27/69, P = 0·005). Multivariate conditional logistic regression showed that the use of insulin [odds ratio (OR) 10·5, 95% confidence interval (CI) 1·5–72·4], antibiotics (OR 4·5, 95% CI 1·4–14·6) and opioids (OR 2·9, 95% CI 1·1–7·8) was also independently associated with hospital‐acquired hyponatraemia. Mortality (6/50 vs. 1/69, P = 0·04) and intensive care admission (15/50 vs. 7/69, P = 0·008) were higher in cases. Conclusions An increase in CRP and the use of insulin, antibiotics and opioids are novel risk factors for hospital‐acquired hyponatraemia. These factors represent interesting new clues regarding the pathophysiology of hospital‐acquired hyponatraemia, suggesting that the acute‐phase response, pain and/or direct drug effects could be involved in the release of antidiuretic hormone.