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Saudi Journal of Kidney Diseases and Transplantation
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ORIGINAL ARTICLE  
Year : 2013  |  Volume : 24  |  Issue : 2  |  Page : 281-285
Prevalence of hyponatremia among patients who used indapamide and hydrochlorothiazide: A single center retrospective study


1 Department of Medicine, King Abdul Aziz Medical City, Riyadh, Saudi Arabia
2 Specialized Diabetes and Endocrine Center, King Fahad Medical City, Riyadh, Saudi Arabia

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Date of Web Publication26-Mar-2013
 

   Abstract 

Hyponatremia is the most frequently encountered electrolyte abnormality among hospitalized patients and thiazide users. In this large single-center retrospective study, we aim to determine the prevalence and risk factors of hyponatremia among patients at the King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia.To the best of our knowledge, this is the first such study in Saudi Arabia. A chart review was done for the years 2011-2012 of all admitted Saudi patients at KAMC who were treated with indapamide and hydrochlorothiazide. A total of 2000 patients were included [1237 females (629 indapamide and 608 hydrochlorothiazide) and 762 males (371 indapamide and 391 hydrochlorothiazide)]. Majority of the patients had type-2 diabetes mellitus (T2DM) with an overall prevalence of 72.2%. The overall prevalence of hyponatremia, regardless of severity, in the indapamide group was 37.3% versus 38.7% in the hydrochlorothiazide group. Stratification for age revealed that older patients had relatively higher levels of sodium (Na) as compared with younger patients, and this inverse association was significant (R = - 0.123; P <0.001). Increasing age, female gender and presence of T2DM were the significant risk factors for hyponatremia, explaining the 4.7% of the variance perceived (P <0.001). Our study suggests that the prevalence of hyponatremia among Saudi thiazide users is relatively high, and more so for the elderly and for those with T2DM. Early identification of this condition is important and caution should be exercised while prescribing thiazide drugs, particularly to those who are most at risk of developing hyponatremia to prevent related complications.

How to cite this article:
Al Qahtani M, Alshahrani A, Alskaini A, Abukhalid N, Al Johani N, Al Ammari M, Al Swaidan L, Binsalih S, Al Sayyari A, Theaby A. Prevalence of hyponatremia among patients who used indapamide and hydrochlorothiazide: A single center retrospective study. Saudi J Kidney Dis Transpl 2013;24:281-5

How to cite this URL:
Al Qahtani M, Alshahrani A, Alskaini A, Abukhalid N, Al Johani N, Al Ammari M, Al Swaidan L, Binsalih S, Al Sayyari A, Theaby A. Prevalence of hyponatremia among patients who used indapamide and hydrochlorothiazide: A single center retrospective study. Saudi J Kidney Dis Transpl [serial online] 2013 [cited 2019 Nov 22];24:281-5. Available from: http://www.sjkdt.org/text.asp?2013/24/2/281/109574

   Introduction Top


Hyponatremia (serum sodium <135 mmol/L) is the most commonly encountered electrolyte disorder in hospital settings, and is often associated with poor prognosis and increased duration of stay in the hospital. [1] In the United States (US), estimates of incidence of mild hyponatremia among hospital patients are as high as 30%. [2] The prevalence of hyponatremia in the US is much lower as compared with European hospitals, where the highest incidence was noted in geriatric wards (22.2%) and nursing homes (18.8%). [3] Although hyponatremia is the most common electrolyte abnormality in ward patients, it nevertheless remains underdiagnosed and, in some instances, mismanaged. [4] Hyponatremia has been significantly linked to mortality and is a predictor of adverse prognosis in patients with heart failure, [5] cirrhosis [6] and pneumonia, [7] to name a few. To date, there is scarcity of information with regard to the epidemiology of hyponatremia in the Kingdom of Saudi Arabia. In this retrospective study, therefore, we aim to determine the prevalence of hyponatremia among Saudi patients admitted at a military tertiary hospital in the Central Region of the Kingdom. Furthermore, we aim to determine the prevalence of hyponatremia among patients on indapamide and hydrochlorothiazide monotherapy and to identify significant predictors related to hyponatremia.


   Methodology Top


This retrospective study was conducted at the Internal Medicine Department of the King Abdulaziz Medical City (KAMC), National Guard Hospital, Riyadh, Saudi Arabia, a tertiary governmental hospital. A total of 2000 adult Saudi patients (18-90 years old) who were admitted between 2011 and 2012 at the KAMC, and who were using either indapamide (n = 1000) or hydrochlorothiazide (n = 1000), were included. Patients who had severe end-stage organ failure (heart failure, renal failure and cirrhosis) and were on other diuretics (furosemide, metolazone, acetazolamide, etc) were excluded. Information gathered included age, gender, type of medication used and presence of diabetes mellitus. Patients' charts were collected using the Legacy Pharmacy Outpatient Program in indapamide and hydrochlorothiazide monotherapy and using the Quadermide Inpatient Program. Mild hyponatremia was defined as serum sodium (Na) of 125-135 mEq/L; moderate hyponatremia was defined as serum Na of 120-124 mEq/L; and severe hyponatremia was defined as serum Na <120 mEq/L.


   Statistical Analysis Top


Statistical Package for Social Sciences (SPSS) version 16.5 (Chicago, IL, USA) was used for the analysis of entered data. Frequencies were expressed as percentage (%) and continuous variables were presented as mean ± standard deviation. Comparison of categorical variables was done using the Chi-square test. Regression analysis was also performed to determine mine significant predictors of hyponatremia using the available variables as independent variables. Significance was set at P <0.05.


   Results Top


In this study involving 2000 reviewed charts of equally distributed patients taking either indapamide or hydrochlorothiazide, there were 1237 females (629 indapamide and 608 hydrochlorothiazide) and 762 males (371 indapamide and 391 hydrochlorothiazide). No signifcant difference was elicited in the age between the two groups studied (indapamide = 62.6 ± 11.6 versus hydrochlorothiazide 63.44 ± 11.8; P = 0.10). Majority of the patients had type-2 diabetes mellitus (T2DM), with an overall prevalence of 72.2%. The overall prevalence of hyponatremia, regardless of severity, in the indapamide group was 37.3% versus 38.7% in the hydrochlorothiazide group. [Figure 1] shows the prevalence of hyponatremia in the two groups based on severity, and it showed no significant difference between the two drugs.
Figure 1: Prevalence of various degrees of severity of hyponatremia among indapamide and hydrochlorothiazide users.

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Stratification for age revealed that older patients had relatively higher levels of Na as compared with younger patients, and this inverse association was significant (R = -0.123; P <0.001) [Figure 2]. [Figure 3] shows the significant difference in the prevalence of hyponatremia among patients with and without T2DM (P <0.001). Regression analysis revealed that increasing age, female gender and presence of T2DM are significant risk factors for hyponatremia, explaining 4.7% of the variance perceived (P <0.001). The type of medication used (indapamide or hydrochlorothiazide) was not a risk factor for hyponatremia.
Figure 2: Mean age of the patients with normal sodium and mild, moderate and severe hyponatremia, showing the significant inverse association between serum sodium and age (R = - 0.123; P <0.001).

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Figure 3: Increased prevalence of mild hyponatremia seen among patients with type-2 diabetes mellitus as compared with those without diabetes.

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   Discussion Top


The main finding of the present cross-sectional and retrospective study is the moderately high prevalence of hyponatremia among the study patients, regardless of the thiazide drug used, and that this is more pronounced among patients with pre-existing T2DM. The findings are comparable more to the reports from the US than from the reports from Europe in terms of prevalence, with the present findings being slightly higher than that of the US. While both medications (indapamide and hydrochlorothiazide) are anti-hypertensive agents known to be capable of inducing hyponatremia, [8],[9] the present study is one of the few to present the severity of thiazide-induced hyponatremia in the Saudi population. Further to this is the presence of T2DM, which, together with insulin use, was recently considered an important risk factor for hospital-acquired hyponatremia. [10] Two of the significant predictors for hyponatremia elicited in this study were non-modifiable: age and gender. Age is a well known risk factor for hyponatremia, probably secondary to age-related decline in renal function. The findings of the present study, indicating the female gender as a risk factor for hyponatremia, should be interpreted with caution as majority of the subjects in this study were females, and this could have affected the results.

The authors acknowledge several limitations. Several confounders were not accounted for, including body mass index (BMI) and other medications that could potentially interfere with sodium regulation. Furthermore, the duration of indapamide or hydrochlorothiazide intake was not taken into account. Nevertheless, the study has several strengths, including the large sample size, and this can be generalizable within the Central Region of Riyadh, KSA, as well as the relatively novel findings with respect to this specific population.

In summary, the prevalence of hyponatremia among Saudi thiazide users is relatively high. Old age and the presence of T2DM are considered major risk factor for the presence of hyponatremia. Early identification and correction of this condition should be implemented and caution should be exercised in prescribing thiazide drugs to those who are already at risk of developing hyponatremia.

 
   References Top

1.Thomspson C, Hoorn EJ. Hyponatremia: An overview of frequency, clinical presentation and complications. Best Pract Res Clin Endocrinol Metab 2012;26 Suppl:S1-6.  Back to cited text no. 1
    
2.Upadhyay A, Jaber BL, Madias NE. Epidemiology of hyponatremia. Semin Nephrol 2009;29:227-38.  Back to cited text no. 2
[PUBMED]    
3.Mannesse CK, Vondeling AM, Van Marum RJ, Van Solinge WW, Egberts TC, Jansen PA. Prevalence of hyponatremia on geriatric wards compared to other settings over four decades: A review. Ageing Res Rev 2013;12:165-73.  Back to cited text no. 3
[PUBMED]    
4.Johannsson G. More focus on hyponatremia-a neglected problem. Lakartidningen 2012; 109:871.  Back to cited text no. 4
[PUBMED]    
5.Rusinaru D, Tribouilloy C, Berry C, et al; on behalf of the MAGGIC Investigators. Relationship of serum sodium concentration to mortality in a wide spectrum of heart failure patients with preserved and with reduced ejection fraction: an individual patient data meta-analysis (dagger): Meta-analysis Global Group in Chronic heart failure (MAGGIC). Eur J Heart Fail 2012;14:1139-46.  Back to cited text no. 5
    
6.Bengus A, Babiuc R. Hyponatremia - a predictor of adverse prognosis in cirrhosis. J Med Life 2012;5:176-8.  Back to cited text no. 6
    
7.Miyashita J, Shimada T, Hunter AJ, Kamiya T. Impact of hyponatremia and the sybndrome of inapparopriate antidiuresis on mortality in elderly patients with aspiration pneumonia. J Hosp Med 2012;7:464-9.  Back to cited text no. 7
[PUBMED]    
8.Glover M, Clayton J. Thiazide-induced hyponatraemia: Epidemiology and clues to pathogenesis. Cardiovasc Ther 2012;30:e219-26.  Back to cited text no. 8
[PUBMED]    
9.Egom EE, Chirico D, Clark AL. A review of thiazide-induced hyponatremia. Clin Med 2011;11:448-51.  Back to cited text no. 9
[PUBMED]    
10.Beukhof CM, Hoorn EJ, Lindermans J, Zietse R. Novel risk factors for hospital acquired hyponatremia: A matched case-control study. Clin Endocrinol (Oxf) 2007;66:367-72.  Back to cited text no. 10
    

Top
Correspondence Address:
M Al Qahtani
Consultant Internal Medicine and Heart Failure Specialist, Assistant Professor and Co-Director of Medicine Block - KSAU-HS, Head Internal Medicine, Department of Medicine, King Abdullaziz Medical City, P. O. Box 22490, Riyadh 11426
Saudi Arabia
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DOI: 10.4103/1319-2442.109574

PMID: 23538350

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    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

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    Abstract
   Introduction
   Methodology
   Statistical Analysis
   Results
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    References
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