Prevalence of hyponatremia among patients who used indapamide and hydrochlorothiazide: A single center retrospective study

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.

Tolerability of Antihypertensive Medications in Older Adults

“…In summary, data regarding the etiology of hyponatremia are inconsistent. Predisposition appears clearly higher with chlorthalidone than with hydrochlorothiazide [31,42], while it is similar between hydrochlorothiazide and indapamide [45]. Hyponatremia and hospitalization due to osteoporotic fractures may result from loop diuretics but not thiazides [54]; this observation may relate to the fact that thiazides induce positive calcium balance, unlike the loop diuretics.…”

“…Hyponatremia, which results from a multitude of causes besides medications, can manifest as delirium, falls, lethargy, stupor, and even seizures, based on the severity and acuity of development. Predisposing factors include increasing age, female sex, larger dose of thiazide or thiazide-like diuretics, presence of hypokalemia, and lower body mass index; different studies suggest the influence of ACEIs to be a predisposition and otherwise [28,[42][43][44][45][46][47][48][49]. In a given individual, besides diuretics, there may well exist other causes for hyponatremia, such as water retention caused by excessive water intake, psychogenic polydipsia, heavy beer intake, and impaired water-excreting ability [50].…”

Hyponatraemia in primary care

“…In older people, up to 75% of those with hyponatraemia are associated with thiazides 12. Thiazide-like drugs indapamide and hydrochorothiazide are also implicated in hyponatraemia 13. Low cost and familiarity make them frequent choices for the treatment of essential hypertension and oedematous states, but they are often implicated in hospital admissions for severe hyponatraemia, which should be factored into clinical decision making and guideline drafting.…”

Hyponatraemia – presentations and management

“…Solute loss can be classified as renal and non-renal. Thiazide diuretic-induced hyponatraemia is the leading cause 28 Other causes of hypovolaemic hyponatraemia include gastrointestinal losses, skin losses (burns and perspiration) and renal salt loss due to salt wasting nephropathy or mineralocorticoid deficiency (eg Addison's disease).…”

“…28 However, treatment with normal saline is reserved for patients in whom the differentiation between hypovolaemia and euvolaemia is difficult. In this situation, intravenous saline is a safer firstline treatment than fluid restriction, but careful monitoring is required in order to ensure improvement in sodium concentrations while on saline.…”