Clinical Features of Hyponatremia: Changes Related to Increasing Use of Thiazide-Combination Diuretics

Cha, In Hye; Cho, Eun Jung; Yoon, Ki Chul; Noh, Hye Jin; Choi, Hye Min; Lee, Jae Won; Jo, Sang Kyung; Kim, Hyoung Kyu; Cho, Won Yong

Abstract

PURPOSE
In this study, the etiology and the change of clinical characteristics of hyponatremia, in relation to the increased used of thiazide diuretics, have been assessed.
METHODS
To perform a retrospective cohort study, a total sum of 322 patients who have been admitted in a single tertiary referral hospital between 2004 and 2009, were included.
RESULTS
The most common cause of hyponatremia was due to thiazide diuretics (37.6%). Among the 121 patients who suffered from thiazide induced hyponatremia, 60 (48.0%) patients took combination thiazide. The incidence of hyponatremia has shown a tendency to increase from 2004 to 2009 (trend test, p<0.001). The incidence of hyponatremia due to the use of combination types has also increased (trend test, p<0.001). Thiazide induced hyponatremia showed no difference when compared to hyponatremia due the other causes, except the fact that the portion of female patients was higher (73.6% vs 64.6%, p<0.001), mean age was older (74.7 vs 69.9 years-old, p<0.001), and incidence of cerebrovascular accident was also higher (19.8% vs 6.5%, p<0.001).
CONCLUSION
The use of thiazide is increasing and hence thiazide-induced hyponatremia is also increasing. This is thought to be particularly related to the increase of thiazide-combined drugs. Thiazideinduced hyponatremia shows a higher incidence in old age, female sex and those who have a history of a cerebrovascular event. Hence more caution is needed when using thiazide diuretics as antihypertensives, and plasma sodium levels should be monitored carefully.