Evaluations of hospitalizations associated with thiazide-associated hyponatremia

Development of a hyponatremia screening tool (ABCDF-S score) for patients with hypertension using thiazide diuretic agents

WHAT IS KNOWN AND OBJECTIVE

Hyponatremia is a common side effect of thiazide diuretics that can lead to increased mortality and hospitalization. A rapid and accurate screening tool is needed for rapid and appropriate management. In this study, we report on the development of a simple clinical screening tool for hyponatremia using thiazide diuretics.

METHODS

This nested case-control study was performed by collecting data from 1 January 2015 to 30 June 2017. Univariable and multivariable logistic regressions were used to identify potential risk factors. The regression coefficients were converted into item scores by dividing each regression coefficient with the minimum coefficient in the model and rounding to the nearest integer. This value was then summed to the total score. The prediction power of the model was determined by the area under the receiver operating characteristic curve (AuROC).

RESULTS AND DISCUSSION

Six clinical risk factors, namely age ≥65 years, benzodiazepine use, history of a cerebrovascular accident, dose of hydrochlorothiazide ≥25 mg, female sex and statin use, were included in our ABCDF-S score. The model showed good power of prediction (AuROC 81.53%, 95% confidence interval [CI]: 78%-84%) and good calibration (Hosmer-Lemeshow X²  = 23.20; P = .39). The positive likelihood ratios of hyponatremia in patients with low risk (score ≤ 6) and high risk (score ≥ 8) were 0.26 (95% CI: 0.21-0.32) and 3.89 (95% CI: 3.11-4.86), respectively.

WHAT IS NEW AND CONCLUSION

The screening tool with six risk predictors provided a useful prediction index for thiazide-associated hyponatremia. However, further validation of the tool is warranted prior to its utilization in routine clinical practice.

A retrospective case-control study evaluating thiazide-induced hyponatraemia-related hospitalisation among older Singaporeans

Introduction:

Thiazide diuretics are recommended as first-line therapy for hypertension in older adults. However, thiazides are also associated with hyponatraemia-related hospitalisations in older patients. This study aims to determine the predictors of hospitalisation due to thiazides usage in older adults.

Methods:

This is a retrospective matched case-control study. Patients aged ⩾65 admitted due to adverse drug reactions based on International Classification of Diseases, Ninth Revision (ICD9) codes from the period of 1 June to 31 December 2011 in Singapore General Hospital were extracted. Patients with the ICD9 code E944.3 Saluretics causing adverse effects in therapeutic use and who experienced thiazide-induced hyponatraemia were identified. Controls were identified from a pool of patients from outpatient clinics who were prescribed thiazide during the study period. Each case was matched to four controls based on gender and race. Patients’ demographics, length of stay, and cost of hospital admission were obtained.

Results:

In total, 19 cases with thiazide-induced hyponatraemia were matched with 76 controls. Cases were older than control (78.8±6.1 vs. 75.6±7.0, p=0.052), with the majority being females (84.2%) and Chinese (94.7%). The mean length of stay was 4 (±3) days; the mean cost of stay was SGD 1118 (±898). Serum potassium levels and concurrent use of beta-blockers were identified as unadjusted possible predictors for hospitalisation due to thiazide-induced hyponatraemia.

Conclusion:

Potential predictors of hospitalisation due to thiazide-induced hyponatraemia include low potassium levels and concurrent use of beta-blockers. Identification of predictors is crucial to guide safe and effective prescribing of thiazides in older patients.

The Economic Burden of Hyponatremia: Systematic Review and Meta-Analysis

BACKGROUND

Hyponatremia is the most common electrolyte abnormality observed in clinical practice. Several studies have demonstrated that hyponatremia is associated with an increased length of hospital stay and of hospital resource utilization. To clarify the impact of hyponatremia on the length of hospitalization and costs, we performed a meta-analysis based on published studies that compared hospital length of stay and cost between patients with and without hyponatremia.

METHODS

An extensive Medline, Embase, and Cochrane search was performed to retrieve all studies published up to April 1, 2015 using the following words: "hyponatremia" or "hyponatraemia" AND "hospitalization" or "hospitalisation." A meta-analysis was performed including all studies comparing duration of hospitalization and hospital readmission rate in subjects with and without hyponatremia.

RESULTS

Of 444 retrieved articles, 46 studies satisfied the inclusion criteria, encompassing a total of 3,940,042 patients; among these, 757,763 (19.2%) were hyponatremic. Across all studies, hyponatremia was associated with a significantly longer duration of hospitalization (3.30 [2.90-3.71; 95% CIs] mean days; P < .000). Similar results were obtained when patients with associated morbidities were analyzed separately. Furthermore, hyponatremic patients had a higher risk of readmission after the first hospitalization (odds ratio 1.32 [1.18-1.48; 95% CIs]; P < .000). A meta-regression analysis showed that the hyponatremia-related length of hospital stay was higher in males (Slope = 0.09 [0.05-0.12; 95% CIs]; P = .000 and Intercept = -1.36 [-3.03-0.32; 95% CIs]; P = .11) and in elderly patients (Slope = 0.002 [0.001-0.003; 95% CIs]; P < .000 and Intercept = 0.89 [0.83-0.97; 95% CIs]; P < .001). A negative association between serum [Na(+)] cutoff and duration of hospitalization was detected. No association between duration of hospitalization, serum [Na(+)], and associated morbidities was observed. Finally, when only US studies (n = 8) were considered, hyponatremia was associated with up to around $3000 higher hospital costs/patient when compared with the cost of normonatremic subjects.

CONCLUSIONS

This meta-analysis confirms that hyponatremia is associated with a prolonged hospital length of stay and higher risk of readmission. These observations suggest that hyponatremia may represent one important determinant of the hospitalization costs.

Association of Thiazide-Type Diuretics With Glycemic Changes in Hypertensive Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

Patients receiving thiazide diuretics have a higher risk of impaired glucose tolerance or even incident diabetes, but the change of blood glucose level varies across different trials. The aim of this study was to investigate the glycemic changes in hypertensive patients with thiazide-type diuretics. Twenty-six randomized trials involving 16,162 participants were included. Thiazide-type diuretics were found to increase fasting plasma glucose (FPG) compared with nonthiazide agents or placebo or nontreatment (mean difference [MD], 0.27 mmol/L [4.86 mg/dL]; 95% confidence interval [CI], 0.15-0.39). Patients receiving lower doses of thiazides (hydrochlorothiazide or chlorthalidone ≤25 mg daily) had less change in FPG (MD, 0.15 mmol/L [2.7 mg/dL]; 95% CI, 0.03-0.27) than those receiving higher doses (MD, 0.60 mmol/L [10.8 mg/dL]; 95% CI, 0.39-0.82), revealed by the subgroup analysis of thiazides vs calcium channel blockers. Thiazide-type diuretics are associated with significant but small adverse glycemic effects in hypertensive patients. Treatment with a lower dose might reduce or avoid glycemic changes.

Dose comparison of conivaptan (Vaprisol®) in patients with euvolemic or hypervolemic hyponatremia--efficacy, safety, and pharmacokinetics

PURPOSE

This study aimed to evaluate the efficacy, safety, and pharmacokinetics of 20 and 40 mg/day conivaptan (Vaprisol®) in patients with hypervolemic or euvolemic hyponatremia.

METHODS

Hyponatremic patients - serum sodium (sNa) ≤130 mEq/L - received either 20 or 40 mg/day of conivaptan for 4 days, following an initial 20 mg loading dose. Efficacy was evaluated by the magnitude and extent of change in sNa. Safety was evaluated by the incidence of adverse events, changes in vital signs and laboratory parameters, rate of sNa correction, and frequency of infusion-site reactions. Pharmacokinetic parameters were also measured.

RESULTS

A total of 37 patients received 20 mg/day and 214 patients received 40 mg/day conivaptan. Baseline-adjusted sNa-area under the concentration-time curve increased by an average of 753.8±499.9 mEq·hr/L (20 mg/day) and 689.2±417.3 mEq·hr/L (40 mg/day) over the course of the 4-day treatment period. The majority of patients in both treatment groups achieved a 4 mEq/L increase in sNa over baseline in ~24 hours (82.5%). Average increase in sNa after 4 days was ~10 mEq/L, varying with dosage level and baseline volume status. Treatment success (normal sNa or increase of ≥6 mEq/L) was attained by 70.3% of patients in the 20 mg/day group and 72.0% in the 40 mg/day group.

CONCLUSION

Both 20 and 40 mg/day doses of conivaptan are efficacious in increasing sNa over 4 days of treatment with no observed increase in the frequency of adverse events or specific infusion-site reactions using the higher dose. The pharmacokinetic parameters of both doses were similar to what has been reported previously, exhibiting greater-than-dose-proportional plasma concentrations.

Clinical and Genetic Factors Associated With Thiazide-Induced Hyponatremia

Thiazide diuretics are associated with an increased risk of hyponatremia. The aim of this study was to investigate possible predictors of thiazide-induced hyponatremia.A total of 48 patients admitted to the ward or to the emergency department due to severe thiazide-induced hyponatremia (Na < 125 mmol/L) were enrolled in our study as the case group. Another 211 hypertensive patients with normal sodium levels after treatment with thiazide diuretics were selected as the control group. Twelve tag single nucleotide polymorphism markers were selected from the Potassium Channel, Inwardly Rectifying Subfamily J, Member 1 (KCNJ1) gene: rs1231254, rs2238009, rs1148058, rs675482, rs673614, rs12795437, rs2855800, rs2509585, rs3016774, rs881333, rs4529890, and rs7116606. Clinical and genetic parameters between patients with thiazide-induced hyponatremia and the control group were compared. Logistic regression was used to analyze data.The patients with thiazide-induced hyponatremia were older (P < 0.001), predominantly female (P = 0.008), had a lower mean body mass index (BMI) (P < 0.001), and more commonly used angiotensin II receptor antagonist (P < 0.001) and spironolactone (P = 0.007) compared with the control groups. Analysis with multivariate logistic regression revealed that age (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.08-1.19, P < 0.001), female gender (OR, 4.49; 95% CI, 1.54-13.11, P = 0.006), BMI (OR, 0.80; 95% CI, 0.69-0.93, P = 0.003), and KCNJ1 rs2509585 C/T or T/T polymorphisms (OR, 5.75; 95% CI, 1.25-26.45, P = 0.03) were independent predictors for thiazide-induced hyponatremia.Older female patients with lower BMIs and KCNJ1 rs2509585 C/T or T/T polymorphisms were more likely to develop thiazide-induced hyponatremia.

A systematic review and meta-analysis of thiazide-induced hyponatraemia: time to reconsider electrolyte monitoring regimens after thiazide initiation?

AIMS

Hyponatraemia is one of the major adverse effects of thiazide and thiazide-like diuretics and the leading cause of drug-induced hyponatraemia requiring hospital admission. We sought to review and analyze all published cases of this important condition.

METHODS

Ovid Medline, Embase, Web of Science and PubMed electronic databases were searched to identify all relevant articles published before October 2013. A proportions meta-analysis was undertaken.

RESULTS

One hundred and two articles were identified of which 49 were single patient case reports. Meta-analysis showed that mean age was 75 (95% CI 73, 77) years, 79% were women (95% CI 74, 82) and mean body mass index was 25 (95% CI 20, 30) kg m(-2) . Presentation with thiazide-induced hyponatraemia occurred a mean of 19 (95% CI 8, 30) days after starting treatment, with mean trough serum sodium concentration of 116 (95% CI 113, 120) mm and serum potassium of 3.3 (95% CI 3.0, 3.5) mm. Mean urinary sodium concentration was 64 mm (95% CI 47, 81). The most frequently reported drugs were hydrochlorothiazide, indapamide and bendroflumethiazide.

CONCLUSIONS

Patients with thiazide-induced hyponatraemia were characterized by advanced age, female gender, inappropriate saliuresis and mild hypokalaemia. Low BMI was not found to be a significant risk factor, despite previous suggestions. The time from thiazide initiation to presentation with hyponatraemia suggests that the recommended practice of performing a single investigation of serum biochemistry 7-14 days after thiazide initiation may be insufficient or suboptimal. Further larger and more systematic studies of thiazide-induced hyponatraemia are required.

A large cohort study evaluating risk factors associated with uncontrolled hypertension

Hypertension is the most common primary diagnosis in the United States. Risks for long-term consequences such as myocardial infarction, heart failure, stroke, and kidney disease continue to significantly increase as long as hypertension remains uncontrolled. This retrospective cohort study of 661,075 patients identified with uncontrolled hypertension, defined as systolic blood pressure (SBP) ≥ 140 mm Hg and/or diastolic blood pressure (DBP) ≥ 90 mm Hg, from a large integrated healthcare organization was conducted to examine multiple patient characteristics to determine their association with uncontrolled hypertension. Multivariate analysis revealed that compared with Caucasians, African Americans (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.16-1.20) were significantly associated with uncontrolled hypertension, as were unpartnered populations (OR, 1.15; 95% CI, 1.14-1.17), number of antihypertensive medications prescribed (OR, 1.37; 95% CI, 1.33-1.41), and adherence to most antihypertensive medications. A secondary analysis found an association between uncontrolled blood pressure and Patient Health Questionnaire-9 (PHQ-9) score (OR, 1.21; 95% CI, 1.16-1.26). Our findings suggest that the presence of these identified risk factors recommends a commitment to a more aggressive hypertension management program to prevent cardiovascular disease caused by uncontrolled hypertension.

Risk of hyponatremia with diuretics: chlorthalidone versus hydrochlorothiazide

BACKGROUND

Chlorthalidone and hydrochlorothiazide are often considered as interchangeable. However, greater (nighttime) blood pressure reduction, and alleged pleiotropic effects have renewed the interest in chlorthalidone. A recent study showed an increased risk of adverse events with chlorthalidone, including hyponatremia.

METHODS

To investigate differences in risk of hyponatremia between chlorthalidone and hydrochlorothiazide, adjusted for daily dose, we conducted a population-based case-control study within the Dutch IPCI (Integrated Primary Care Information) database. The study population included all subjects ≥18 years without diabetes mellitus, heart failure, liver failure, and malignancy, who were registered in the IPCI database from 1996 to 2011. Cases were subjects with a serum sodium <130 millimoles per liter or hospitalization due to hyponatremia. Controls were matched on practice, age within 5 years, sex, and date of onset.

RESULTS

A total of 1033 cases of hyponatremia were identified. Hyponatremia was more common with chlorthalidone than with hydrochlorothiazide at equal dose per day: adjusted odds ratio was 2.09 (95% confidence interval [CI], 1.13-3.88) for 12.5 milligrams per day and 1.72 (95% CI, 1.15-2.57) for 25 milligrams per day. Risks were not significantly increased with chlorthalidone compared with twice the dose per day of hydrochlorothiazide.

CONCLUSIONS

This is the first study that shows an increased risk of hyponatremia with chlorthalidone relative to hydrochlorothiazide at equal milligram-to-milligram dose per day. The need for a lower dose of chlorthalidone than hydrochlorothiazide to achieve similar blood pressure reduction likely compensates for the increased risk of hyponatremia at equal dose.

Combination therapy of angiotensin II receptor blocker and thiazide produces severe hyponatremia in elderly hypertensive subjects

Thiazide diuretics are known to produce severe hyponatremia as well as hypokalemia. The present study demonstrated severe hyponatremia in three hypertensive patients who had received combination therapy consisting of an angiotensin II receptor blocker (ARB) and thiazide. The serum sodium (Na) levels in all three cases were markedly reduced to below 116 mmol/L, and the patients exhibited augmented urinary excretion of Na with a reduced circulatory blood volume. After withdrawing the ARB and thiazide treatment, the serum Na levels normalized within one to two weeks. Combination therapy with ARBs and thiazide may cause hyponatremia in elderly patients.

Adverse drug events as a cause of hospitalization in older adults

Older adults are about four to seven times more likely than younger persons to experience adverse drug events (ADEs) that cause hospitalization, especially if they are women and take multiple medications. The prevalence of drug-related hospitalizations has been reported to be as high as 31%, with large heterogeneity between different studies, depending on study setting (all hospital admissions or only acute hospital admissions), study population (entire hospital, specific wards, selected population and/or age groups), type of drug-related problem measured (adverse drug reaction or ADE), method of data collection (chart review, spontaneous reporting or database research) and method and definition used to detect ADEs. The higher risk of drug-related hospitalizations in older adults is mainly caused by age-related pharmacokinetic and pharmacodynamic changes, a higher number of chronic conditions and polypharmacy, which is often associated with the use of potentially inappropriate drugs. Other factors that have been involved are errors related to prescription or administration of drugs, medication non-adherence and inadequate monitoring of pharmacological therapies. A few commonly used drugs are responsible for the majority of emergency hospitalizations in older subjects, i.e. warfarin, oral antiplatelet agents, insulin and oral hypoglycaemic agents, central nervous system agents. The aims of the present review are to summarize recent evidence concerning drug-related hospitalization in older adults, to assess the contribution of specific medications, and to identify potential interventions able to reduce the occurrence of these drug-related events, as they are, at least partly, potentially preventable.

Laxative use and incident falls, fractures and change in bone mineral density in postmenopausal women: results from the Women's Health Initiative

Background

Laxatives are among the most widely used over-the-counter medications in the United States but studies examining their potential hazardous side effects are sparse. Associations between laxative use and risk for fractures and change in bone mineral density [BMD] have not previously been investigated.

Methods

This prospective analysis included 161,808 postmenopausal women (8907 users and 151,497 nonusers of laxatives) enrolled in the WHI Observational Study and Clinical Trials. Women were recruited from October 1, 1993, to December 31, 1998, at 40 clinical centers in the United States and were eligible if they were 50 to 79 years old and were postmenopausal at the time of enrollment. Medication inventories were obtained during in-person interviews at baseline and at the 3-year follow-up visit on everyone. Data on self-reported falls (≥2), fractures (hip and total fractures) were used. BMD was determined at baseline and year 3 at 3 of the 40 clinical centers of the WHI.

Results

Age-adjusted rates of hip fractures and total fractures, but not for falls were similar between laxative users and non-users regardless of duration of laxative use. The multivariate-adjusted hazard ratios for any laxative use were 1.06 (95% confidence interval [CI], 1.03-1.10) for falls, 1.02 (95% CI, 0.85-1.22) for hip fractures and 1.01 (95% CI, 0.96-1.07) for total fractures. The BMD levels did not statistically differ between laxative users and nonusers at any skeletal site after 3-years intake.

Conclusion

These findings support a modest association between laxative use and increase in the risk of falls but not for fractures. Its use did not decrease bone mineral density levels in postmenopausal women. Maintaining physical functioning, and providing adequate treatment of comorbidities that predispose individuals for falls should be considered as first measures to avoid potential negative consequences associated with laxative use.