Thiazide-associated hyponatremia in arterial hypertension patients: A nationwide population-based cohort study

OBJECTIVE

Thiazides are the first-line treatment for hypertension, however, they have been associated with hospitalizations for thiazide-associated hyponatremia (TAH). The aim of this study was to evaluate the risk of TAH and other drug-associated hyponatremia in a Korean population.

METHODS

The study used big data from the National Health Insurance Sharing Service of 1,943,345 adults treated for hypertension from January 2014 to December 2016. The participants were divided into two groups based on the use of thiazides. Cox proportional hazard models were used to identify independent risk factors for the occurrence of hyponatremia.

RESULTS

The study found that hyponatremia-related hospitalizations were significantly higher in the thiazide group than the control group (2.19% vs. 1.45%). The risk increased further with concurrent use of other diuretics or desmopressin, and thiazide+spironolactone+desmopressin and hospitalization risk further increased (4.0 and 6.9 times). Multivariate analysis showed that hyponatremia occurrence increased with age, diabetes mellitus, depression, and thiazide use (hazard ratio = 1.436, p < 0.001). The thiazide group had better 6-year overall survival than the control group but had more fractures and hyponatremia.

CONCLUSIONS

Thiazide use is associated with an increased risk of hyponatremia and related complications. However, the mortality rate decreased in those who received thiazides, suggesting that thiazide use itself is not harmful and may help decrease complications and improve prognosis with proper, cautious use in high-risk patients.

Machine Learning Insights Into Uric Acid Elevation With Thiazide Therapy Commencement and Intensification

Background Elevated serum uric acid, associated with cardiovascular conditions such as atherosclerotic heart disease, hypertension, and heart failure, can be elevated by thiazide or thiazide-like drugs (THZ), essential in hypertension management. Identifying clinical determinants affecting THZ-related uric acid elevation is critical. Methods In this retrospective cross-sectional study, we explored the clinical determinants influencing uric acid elevation related to THZ, focusing on patients where THZ was initiated or the dose escalated. A cohort of 143 patients was analyzed, collecting baseline and control uric acid levels, alongside basic biochemical studies and clinical data. Feature selection was conducted utilizing criteria based on mean squared error increase and enhancement in node purity. Four machine learning algorithms - Random Forest, Neural Network, Support Vector Machine, and Gradient Boosting regressions - were applied to pinpoint clinical influencers. Results Significant features include uncontrolled diabetes, index estimated Glomerular Filtration Rate (eGFR) level, absence of insulin, action of indapamide, and absence of statin treatment, with absence of Sodium-glucose cotransporter 2 inhibitors (SGLT2i), low dose aspirin exposure, and older age also being noteworthy. Among the applied models, the Gradient Boosting regression model outperformed the others, exhibiting the lowest Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE) values, and the highest R2 value (0.779). While Random Forest and Neural Network regression models were able to fit the data adequately, the Support Vector Machine demonstrated inferior metrics. Conclusions Machine learning algorithms are adept at accurately identifying the factors linked to uric acid fluctuations caused by THZ. This proficiency aids in customizing treatments more effectively, reducing the need to unnecessarily avoid THZ, and providing guidance on its use to prevent instances where uric acid levels could become problematic.

How to optimize the use of diuretics in patients with heart failure?

Considering the pathophysiology and clinical presentation of heart failure, using diuretics or drugs with diuretic properties is indispensable for adequate management of heart failure patients. However, in clinical practice, fluid expansion is often undiagnosed, and diuretic therapy is not always adequately titrated. Today, several drug classes with diuretic properties are available in addition to classical thiazides, thiazide-like, and loop diuretics. The purpose of this short review is to discuss different ways to optimize diuretic therapy using currently available drugs. Several approaches are considered, including a combination of diuretics to obtain a sequential nephron blockade, use of a drug combining a blocker of the renin-angiotensin system (RAS) and an inhibitor of the metabolism of natriuretic peptides (ARNI), prescription of potassium binders to maintain and up-titrate RAS blockers and mineralocorticoid antagonists, and finally use of inhibitors of renal reabsorption of glucose through the sodium-glucose cotransporter 2 system. Optimal use of these various drug classes should improve the quality of life and reduce the need for hospital admissions and mortality in heart failure patients.

First-line diuretics versus other classes of antihypertensive drugs for hypertension

BACKGROUND

Different first-line drug classes for patients with hypertension are often assumed to have similar effectiveness with respect to reducing mortality and morbidity outcomes, and lowering blood pressure. First-line low-dose thiazide diuretics have been previously shown to have the best mortality and morbidity evidence when compared with placebo or no treatment. Head-to-head comparisons of thiazides with other blood pressure-lowering drug classes would demonstrate whether there are important differences.

OBJECTIVES

To compare the effects of first-line diuretic drugs with other individual first-line classes of antihypertensive drugs on mortality, morbidity, and withdrawals due to adverse effects in patients with hypertension. Secondary objectives included assessments of the need for added drugs, drug switching, and blood pressure-lowering.

SEARCH METHODS

Cochrane Hypertension's Information Specialist searched the Cochrane Hypertension Specialized Register, CENTRAL, MEDLINE, Embase, and trials registers to March 2021. We also checked references and contacted study authors to identify additional studies. A top-up search of the Specialized Register was carried out in June 2022.

SELECTION CRITERIA

Randomized active comparator trials of at least one year's duration were included. Trials had a clearly defined intervention arm of a first-line diuretic (thiazide, thiazide-like, or loop diuretic) compared to another first-line drug class: beta-blockers, calcium channel blockers, alpha adrenergic blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, direct renin inhibitors, or other antihypertensive drug classes. Studies had to include clearly defined mortality and morbidity outcomes (serious adverse events, total cardiovascular events, stroke, coronary heart disease (CHD), congestive heart failure, and withdrawals due to adverse effects).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 20 trials with 26 comparator arms randomizing over 90,000 participants. The findings are relevant to first-line use of drug classes in older male and female hypertensive patients (aged 50 to 75) with multiple co-morbidities, including type 2 diabetes. First-line thiazide and thiazide-like diuretics were compared with beta-blockers (six trials), calcium channel blockers (eight trials), ACE inhibitors (five trials), and alpha-adrenergic blockers (three trials); other comparators included angiotensin II receptor blockers, aliskiren (a direct renin inhibitor), and clonidine (a centrally acting drug). Only three studies reported data for total serious adverse events: two studies compared diuretics with calcium channel blockers and one with a direct renin inhibitor. Compared to first-line beta-blockers, first-line thiazides probably result in little to no difference in total mortality (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.84 to 1.10; 5 trials, 18,241 participants; moderate-certainty), probably reduce total cardiovascular events (5.4% versus 4.8%; RR 0.88, 95% CI 0.78 to 1.00; 4 trials, 18,135 participants; absolute risk reduction (ARR) 0.6%, moderate-certainty), may result in little to no difference in stroke (RR 0.85, 95% CI 0.66 to 1.09; 4 trials, 18,135 participants; low-certainty), CHD (RR 0.91, 95% CI 0.78 to 1.07; 4 trials, 18,135 participants; low-certainty), or heart failure (RR 0.69, 95% CI 0.40 to 1.19; 1 trial, 6569 participants; low-certainty), and probably reduce withdrawals due to adverse effects (10.1% versus 7.9%; RR 0.78, 95% CI 0.71 to 0.85; 5 trials, 18,501 participants; ARR 2.2%; moderate-certainty). Compared to first-line calcium channel blockers, first-line thiazides probably result in little to no difference in total mortality (RR 1.02, 95% CI 0.96 to 1.08; 7 trials, 35,417 participants; moderate-certainty), may result in little to no difference in serious adverse events (RR 1.09, 95% CI 0.97 to 1.24; 2 trials, 7204 participants; low-certainty), probably reduce total cardiovascular events (14.3% versus 13.3%; RR 0.93, 95% CI 0.89 to 0.98; 6 trials, 35,217 participants; ARR 1.0%; moderate-certainty), probably result in little to no difference in stroke (RR 1.06, 95% CI 0.95 to 1.18; 6 trials, 35,217 participants; moderate-certainty) or CHD (RR 1.00, 95% CI 0.93 to 1.08; 6 trials, 35,217 participants; moderate-certainty), probably reduce heart failure (4.4% versus 3.2%; RR 0.74, 95% CI 0.66 to 0.82; 6 trials, 35,217 participants; ARR 1.2%; moderate-certainty), and may reduce withdrawals due to adverse effects (7.6% versus 6.2%; RR 0.81, 95% CI 0.75 to 0.88; 7 trials, 33,908 participants; ARR 1.4%; low-certainty). Compared to first-line ACE inhibitors, first-line thiazides probably result in little to no difference in total mortality (RR 1.00, 95% CI 0.95 to 1.07; 3 trials, 30,961 participants; moderate-certainty), may result in little to no difference in total cardiovascular events (RR 0.97, 95% CI 0.92 to 1.02; 3 trials, 30,900 participants; low-certainty), probably reduce stroke slightly (4.7% versus 4.1%; RR 0.89, 95% CI 0.80 to 0.99; 3 trials, 30,900 participants; ARR 0.6%; moderate-certainty), probably result in little to no difference in CHD (RR 1.03, 95% CI 0.96 to 1.12; 3 trials, 30,900 participants; moderate-certainty) or heart failure (RR 0.94, 95% CI 0.84 to 1.04; 2 trials, 30,392 participants; moderate-certainty), and probably reduce withdrawals due to adverse effects (3.9% versus 2.9%; RR 0.73, 95% CI 0.64 to 0.84; 3 trials, 25,254 participants; ARR 1.0%; moderate-certainty). Compared to first-line alpha-blockers, first-line thiazides probably result in little to no difference in total mortality (RR 0.98, 95% CI 0.88 to 1.09; 1 trial, 24,316 participants; moderate-certainty), probably reduce total cardiovascular events (12.1% versus 9.0%; RR 0.74, 95% CI 0.69 to 0.80; 2 trials, 24,396 participants; ARR 3.1%; moderate-certainty) and stroke (2.7% versus 2.3%; RR 0.86, 95% CI 0.73 to 1.01; 2 trials, 24,396 participants; ARR 0.4%; moderate-certainty), may result in little to no difference in CHD (RR 0.98, 95% CI 0.86 to 1.11; 2 trials, 24,396 participants; low-certainty), probably reduce heart failure (5.4% versus 2.8%; RR 0.51, 95% CI 0.45 to 0.58; 1 trial, 24,316 participants; ARR 2.6%; moderate-certainty), and may reduce withdrawals due to adverse effects (1.3% versus 0.9%; RR 0.70, 95% CI 0.54 to 0.89; 3 trials, 24,772 participants; ARR 0.4%; low-certainty). For the other drug classes, data were insufficient. No antihypertensive drug class demonstrated any clinically important advantages over first-line thiazides.

AUTHORS' CONCLUSIONS

When used as first-line agents for the treatment of hypertension, thiazides and thiazide-like drugs likely do not change total mortality and likely decrease some morbidity outcomes such as cardiovascular events and withdrawals due to adverse effects, when compared to beta-blockers, calcium channel blockers, ACE inhibitors, and alpha-blockers.

Thiazides Attenuate Insulin Secretion Through Inhibition of Mitochondrial Carbonic Anhydrase 5b in β -Islet Cells in Mice

SIGNIFICANCE STATEMENT

Thiazide diuretics (thiazides) are among the most widely prescribed drugs worldwide, but their use is associated with glucose intolerance and new-onset diabetes mellitus. The molecular mechanisms remain elusive. Our study reveals that thiazides attenuate insulin secretion through inhibition of the mitochondrial carbonic anhydrase isoform 5b (CA5b) in pancreatic β cells. We furthermore discovered that pancreatic β cells express only one functional carbonic anhydrase isoform, CA5b, which is critical in replenishing oxaloacetate in the mitochondrial tricarboxylic acid (TCA) cycle (anaplerosis). These findings explain the mechanism for thiazide-induced glucose intolerance and reveal a fundamental role of CA5b in TCA cycle anaplerosis and insulin secretion in β cells.

BACKGROUND

Thiazide diuretics are associated with glucose intolerance and new-onset diabetes mellitus. Previous studies demonstrated that thiazides attenuate insulin secretion, but the molecular mechanisms remain elusive. We hypothesized that thiazides attenuate insulin secretion via one of the known molecular thiazide targets in β cells.

METHODS

We performed static insulin secretion experiments with islets of wild-type, Sodium/chloride co-transporter (NCC) (SLC12A3), and sodium-driven chloride/bicarbonate exchanger (NDCBE) (SLC4A8) knock-out (KO) mice and with murine Min6 cells with individual knockdown of carbonic anhydrase (CA) isoforms to identify the molecular target of thiazides in β cells. CA isoform 5b (CA5b) KO mice were then used to assess the role of the putative thiazide target CA5b in β -cell function and in mediating thiazide sensitivity in vitro and in vivo .

RESULTS

Thiazides inhibited glucose- and sulfonylurea-stimulated insulin secretion in islets and Min6 cells at pharmacologically relevant concentrations. Inhibition of insulin secretion by thiazides was CO 2 /HCO 3- -dependent, not additive to unselective CA inhibition with acetazolamide, and independent of extracellular potassium. By contrast, insulin secretion was unaltered in islets of mice lacking the known molecular thiazide targets NCC or NDCBE. CA expression profiling with subsequent knockdown of individual CA isoforms suggested mitochondrial CA5b as a molecular target. In support of these findings, thiazides significantly attenuated Krebs cycle anaplerosis through reduction of mitochondrial oxaloacetate synthesis. CA5b KO mice were resistant to thiazide-induced glucose intolerance, and thiazides did not alter insulin secretion in CA5b KO islets.

CONCLUSIONS

Thiazides attenuate insulin secretion via inhibition of the mitochondrial CA5b isoform in β cells of mice.

Thiazide diuretics alone or combined with potassium-sparing diuretics to treat hypertension: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

The magnitude of blood pressure (BP)-lowering effects and decrease of the adverse effects of thiazide diuretics provided by potassium-sparing diuretics remain uncertain. The aim of this study was to compare the BP-lowering efficacy and the incidence of adverse effects of high (T+) and low-dose (T-) thiazide diuretics, alone or combined with high (PS+) or low-dose (PS-) potassium-sparing diuretics in patients with primary hypertension.

METHODS

A systematic literature search was performed in PubMed/MEDLINE, the Cochrane Central Register of Controlled Trials, Embase, Web of Science, Scopus and LILACS. Randomized double-blind placebo or active-controlled trials (RCT) with 3 weeks to 1 year of follow-up were included. Sample size, mean and standard deviation from baseline, follow-up and change from baseline values were extracted by two independent reviewers. Pairwise random effect models and Bayesian network meta-analysis models were used to compare the effects of treatments. The risk of bias in individual studies was assessed using the Rob 1.0 tool. The primary outcome was the mean difference in office SBP. Secondary outcomes were the mean difference in biochemical parameters and the incidence of nonmelanoma skin cancer.

RESULTS

Two hundred and seventy-six double-blind RCTs involving 58 807 participants (mean age: 55 years; 45% women) were included. All treatment groups were more effective than placebo in lowering BP, with mean differences (MDs) of change from baseline ranging from -7.66 mmHg [95% credible interval (95% CrI), -8.53 to -6.79] for T- to -12.77 mmHg (95% CrI, -15.22 to -10.31) for T+PS-. T+ alone or combined with potassium-sparing was more effective in reducing BP than T-. The surface under the cumulative ranking curve (SUCRA) estimated ranking showed that the best effectiveness in lowering SBP was found for T+PS- (0.69), T+PS+ (0.65) and T+ (0.54). Compared with placebo, all treatments (except T-PS-) were associated with more potassium reduction and T+ compared with all other treatments and T- when compared with T-PS-. Compared with placebo, all active treatments (except T+PS+) showed higher elevations of uric acid. The increase of plasma glucose promoted by thiazides alone was reduced by potassium-sparing agents.

CONCLUSION

Thiazides with potassium-sparing diuretics are associated with increased BP-lowering efficacy compared with thiazides alone while minimizing hypokalaemia and hyperglycaemia. These findings demonstrate that thiazide and potassium-sparing diuretic combination is preferable to thiazide alone in treating hypertension.

The Urine Calcium/Creatinine Ratio and Uricemia during Hyponatremia of Different Origins: Clinical Implications

Background: Chronic hyponatremia is known to be associated with osteoporosis. It has been shown that chronic hyponatremia increases bone resorption in an attempt to release body stores of exchangeable sodium by different mechanisms. We wanted to know the calciuria of patients with hyponatremia of different origins. Material and Methods: We made a retrospective study of 114 consecutive patients with asymptomatic hyponatremia of different origins with the usual serum and urine chemistry. Result: In hyponatremia due to SIADH, we had a high urine calcium/creatinine ratio of 0.23 ± 0.096 while in patients with salt depletion the UCa/UCr ratio was low (0.056 ± 0.038), in patients with hyponatremia secondary to thiazide intake the value was also low (0.075 ± 0.047) as in hypervolemic patients (0.034 ± 0.01). In hyponatremia due to polydipsia, the value was high (0.205 ± 0.10). Correction of hyponatremia in the euvolemic patients was associated with a significant decrease in the UCa/UCr ratio. In patients with hyponatremia secondary to thiazide intake, we noted that in the patients with low uric acid levels (<4 mg/dL, suggesting euvolemia) we also observed a low UCa/UCr (<0.10). In nine patients with chronic SIADH (SNa 125.1 ± 3.6 mEq/L), the 24 h urine calcium excretion was 275 ± 112 mg and decreased to 122 ± 77 mg (p < 0.01) after at least 2 weeks of treatment. Conclusions: Patients with chronic hyponatremia due to SIADH usually have a high UCa/UCr ratio (>0.15). This is also observed in hyponatremia secondary to polydipsia. Patients with thiazide-induced hyponatremia usually have low UCa/UCr levels and this is the case even among those with a biochemistry similar to that in SIADH (uric acid < 4 mg/dL).

Thiazides in chronic kidney disease: "back to the future"

The thiazide class diuretics are first-line agents for managing hypertension either as monotherapy or as a fixed-dose combination with other antihypertensive drugs. However, despite the extensive experience with these drugs for >60 years, there is general reluctance to use these agents in patients with advanced chronic kidney disease (CKD) because of concerns about their efficacy and safety as kidney function declines. In this issue of Clinical Kidney Journal, Minutolo et al. performed an updated review of the pharmacological properties, efficacy and side effects and randomized controlled trials that tested these drugs in patients with CKD.

Thiazide diuretics are back in CKD: the case of chlorthalidone

Sodium and volume excess is the fundamental risk factor underlying hypertension in chronic kidney disease (CKD) patients, who represent the prototypical population characterized by salt-sensitive hypertension. Low salt diets and diuretics constitute the centrepiece for blood pressure control in CKD. In patients with CKD stage 4, loop diuretics are generally preferred to thiazides. Furthermore, thiazide diuretics have long been held as being of limited efficacy in this population. In this review, by systematically appraising published randomized trials of thiazides in CKD, we show that this class of drugs may be useful even among people with advanced CKD. Thiazides cause a negative sodium balance and reduce body fluids by 1-2 l within the first 2-4 weeks and these effects go along with improvement in hypertension control. The recent CLICK trial has documented the antihypertensive efficacy of chlorthalidone, a long-acting thiazide-like diuretic, in stage 4 CKD patients with poorly controlled hypertension. Overall, chlorthalidone use could be considered in patients with treatment-resistant hypertension when spironolactone cannot be administered or must be withdrawn due to side effects. Hyponatremia, hypokalaemia, volume depletion and acute kidney injury are side effects that demand a vigilant attitude by physicians prescribing these drugs. Well-powered randomized trials assessing hard outcomes are still necessary to more confidently recommend the use of these drugs in advanced CKD.

Increased Mortality in Elderly Patients Admitted with Hyponatremia: A Prospective Cohort Study

Hyponatremia is the most common electrolyte disorder, commonly affecting older hospitalized individuals; however, the literature is not clear regarding its effect on mortality. The aim of this 2-year observational prospective cohort study was to evaluate the mortality and re-admission rates, the clinical and laboratory characteristics and the causes of hyponatremia in patients older than 65 years admitted with a corrected serum sodium of 130 mEq/L or less in an internal medicine ward of a tertiary Greek university hospital. During the observation period, 138 patients (mean age 80.5 years, 36.2% male) fulfilled the inclusion criteria and were prospectively followed for 1 year after admission. Symptoms of hyponatremia were present in 59.4% of patients. Hypovolemia was the main sole cause of hyponatremia, but in about one third of patients, hyponatremia was multifactorial. Only a low proportion of patients (12.3%) fulfilled the criteria of the syndrome of inappropriate antidiuresis (SIAD) at admission according to the current guidelines. The re-admission rates at 3- and 12-months following discharge was 34.2% and 51.8%, respectively. Mortality during hospitalization was 17.4% and was higher compared to non-hyponatremic admitted older patients, while the total mortality at 1 year after admission was 28.3%, indicating that hyponatremia at admission is a marker of significant mortality during and after hospitalization in elderly patients.

Severe Electrolyte Disturbances Complicated by Seizures and Acute Kidney Injury Within 10 Days of Starting Indapamide

Indapamide is one of the most effective and well-known anti-hypertensive medications. Electrolyte disturbances have been classically recognized as a typical side effect profile of indapamide. The most common electrolyte imbalance described with indapamide was hypokalemia; however, hyponatremia is being increasingly reported. In this case, we report a unique form of severe electrolytes derangement (hyponatremia, hypokalemia, hypophosphatemia, and hypocalcemia), which was complicated by seizures, rhabdomyolysis, and acute kidney injury that occurred within only 10 days of indapamide initiation. The patient was admitted to the medical intensive care unit for prompt electrolyte replacement and close monitoring. With the discontinuation of indapamide and the prompt replacement of the deficient electrolytes, the patient's condition has improved dramatically, and he was discharged in a good state of health. Electrolyte disturbances are expected to be seen with indapamide usage, and it might be associated with severe consequences like arrhythmias and seizures. This case report would raise awareness and add to the importance of closely following patients after prescribing indapamide.

Regression of the Left Ventricular Hypertrophy in Patients with Essential Hypertension on Standard Drug Therapy

 PURPOSE: The American College of Cardiology/ American Heart Association 2017 and European Society of Cardiology/European Society of Hypertension 2018 guidelines were a paradigm shift in hypertension management in contemporary medicine. Lowering of blood pressure to less than 130 (systolic) and 80 (diastolic) mm of Hg irrespective of cardiovascular risk is recommended. While intensive blood pressure control is commonly achievable with rational pharmacotherapy, the magnitude of left ventricular hypertrophy regression is an independent factor in improvement in cardiovascular health. The regression of left ventricular hypertrophy has been adjudged as a clinically useful surrogate marker that reflects the efficacy of hypertension treatment. Though angiotensin converting enzyme inhibitors/ angiotensin receptor blockers (ACEI/ARB) are the preferred initial drug for greater regression of left ventricular mass, the choice of add-on therapy, if required, is still debatable. Therefore, in our observational study, we sought to compare the reduction in left ventricular mass index in hypertensives with left ventricular hypertrophy on standard ACEI/ARB based drug therapy.  MATERIALS AND METHODS: The cohort (n=217) comprised of patients with uncontrolled hypertension (blood pressure>140/90 mm of Hg) and left ventricular hypertrophy (left ventricular mass index>115 and 95 gram/square meter in males and females respectively). The add-on drug in ACEI/ARB therapy was either thiazide diuretics (TD) or calcium channel blockers (CCB). Four sub-cohorts were constituted: mono-therapy - group A (n=70, ACEI/ARB), dual-therapy - group B (n=48, ACEI/ARB+TD) and  group C (n=51, ACEI/ ARB+CCB), triple therapy - group D (n=48, ACEI/ ARB+TD+CCB). Left ventricular mass index was determined using echocardiography at baseline and after 24 weeks of therapy.  RESULTS: There was no significant difference in baseline clinical or demographic variables between group B and group C. Baseline blood pressure and duration of hypertension was greater in group D compared to group A (P<0.001). The reduction in left ventricular mass index (mean ±SD) in the four groups (A to D) was 16.7±18.7, 21.0±20.8, 20.5±15.5  and 29.1±21.5 g/m2  respectively (D>A, P=0.011, B versus C, P=1.00). The corresponding change in blood pressure (systolic/diastolic) was 18.5±13.6/8.9±11.2, 27.5±19.2/12.2±9.3, 23.4±16.7/ 5.4±10.1, 26.6±19.5/10.7±12.8 mm of Hg respectively (systolic, B>A, P=0.027, D>A, P=0.048) (diastolic, B>C, P=0.013).  CONCLUSION: Anti-hypertensive treatment with angiotensin converting enzyme inhibitors/angiotensin receptor blockers-based therapy produced graded regression of left ventricular hypertrophy with monotherapy, dual therapy and triple therapy.  In dual therapy, add-on of either thiazide diuretics or calcium channel blockers to angiotensin converting enzyme inhibitors/angiotensin receptor blockers showed equal efficacy in regression of left ventricular hypertrophy independent of blood pressure reduction.

Metabolic and Cardiovascular Effects of Switching Thiazides to Amlodipine in Hypertensive Patients With and Without Type 2 Diabetes (the Diuretics and Diabetes Control Study)

Background: Different studies have indicated that thiazide diuretics can increase the risk of developing type 2 diabetes (T2D). Therefore, in this study, we investigated whether switching from hydrochlorothiazide (HCTZ) to amlodipine resulted in ameliorating different cardiovascular and metabolic measures in hypertensive patients with or without T2D. Methods: This study [Diuretics and Diabetes Control (DiaDiC)] was a 6-week, single-blind, single-center randomized controlled trial. The first 20 normal glucose-tolerant, 20 prediabetic, and 20 T2D consecutive patients were randomized to continue the previous antihypertensive treatment with HCTZ (12.5-25 mg/day) or to switch from HCTZ to amlodipine (2.5-10 mg/day). The primary endpoints were the absolute change in 7-day continuous subcutaneous glucose monitoring (CSGM) glycemia, serum uric acid concentrations, and endothelial function [measured as flow-mediated dilation (FMD)]. Other secondary endpoints were investigated, including changes in glycated hemoglobin (HbA₁c), glycemic variability from 7-day CSGM, and the estimated glomerular filtration rate (eGFR). Results: Amlodipine treatment was associated with a significant reduction in HbA₁c (P = 0.03) for both 7-day CSGM glycemia (P = 0.01) and glycemic variability (coefficient of variability %: HCTZ +3%, amlodipine -2.8%), and a reduction in uric acid concentrations (P < 0.001), especially in participants with T2D or prediabetes. Following amlodipine treatment, a significant increase in both eGFR (P = 0.01) and FMD (P = 0.02) was also observed. Conclusions: This study demonstrates that the replacement of HCTZ with amlodipine has several metabolic and cardiovascular beneficial effects. However, further intervention studies are necessary to confirm the clinical effects of thiazides, especially in diabetic people and in those at risk of diabetes.

Inhibition of AT2R and Bradykinin Type II Receptor (BK2R) Compromises High K+ Intake-Induced Renal K+ Excretion

The inhibition of Type II angiotensin II receptor (AT2R) or BK2R (bradykinin type II receptor) stimulates basolateral Kir4.1/Kir5.1 in the distal convoluted tubule (DCT) and activates thiazide-sensitive NCC (Na-Cl cotransporter). The aim of the present study is to examine the role of AT2R and BK2R in mediating the effect of HK (high dietary K⁺) intake on the basolateral K⁺ channels, NCC, and renal K⁺ excretion. Feeding mice (male and female) with HK diet for overnight significantly decreased the basolateral K⁺ conductance, depolarized the DCT membrane, diminished the expression of pNCC (phosphorylated NCC) and tNCC (total NCC), and decreased thiazide-sensitive natriuresis. Overnight HK intake also increased the expression of cleaved ENaC-α and -γ subunits but had no effect on NKCC2 expression. Pretreatment of the mice (male and female) with PD123319 and HOE140 stimulated the expression of tNCC and pNCC, augmented hydrochlorothiazide-induced natriuresis, and increased the negativity of the DCT membrane. The deletion of Kir4.1 not only decreased the NCC activity but also abolished the stimulatory effect of PD123319 and HOE140 perfusion on NCC activity. Moreover, the effect of overnight HK loading on Kir4.1/Kir5.1 in the DCT and NCC expression/activity was compromised in the mice treated with AT2R/BK2R antagonists. Renal clearance study showed that inhibition of AT2R and BK2R impairs renal K⁺ excretion in response to overnight HK loading, and the mice pretreated with PD123319 and HOE140 were hyperkalemic during HK intake. We conclude that synergistic activation of AT2R and BK2R is required for the effect of overnight HK diet on Kir4.1/Kir5.1 in the DCT and NCC activity.

Antihypertensive Medication Adherence and Confirmation of True Refractory Hypertension

Refractory hypertension (RfHTN) is a phenotype of antihypertensive treatment failure defined as uncontrolled BP despite the use of effective doses of ≥5 antihypertensive medications including a long-acting thiazide-like diuretic (chlorthalidone) and a mineralocorticoid receptor antagonist. The degree of medication nonadherence is unknown among patients with RfHTN. In this prospective evaluation, 54 patients with apparent RfHTN were recruited from the University of Alabama at Birmingham Hypertension Clinic after having uncontrolled BP at 3 or more clinic visits. All patients' BP was evaluated by automated office BP and 24-hour ambulatory BP monitoring (n=49). Antihypertensive medication adherence was determined by measuring 24-hour urine specimens for antihypertensive medications and their metabolites by high-performance liquid chromatography-tandem mass spectrometry (n=45). Of the 45 patients who completed 24-hour ambulatory BP monitoring, 40 (88.9%) had confirmed RfHTN based on an elevated automated office BP (≥130/80 mm Hg), mean 24-hour ABP (≥125/75 mm Hg), and mean awake (day-time) ABP (≥130/80 mm Hg). Out of the 40 fully evaluated patients with RfHTN, 16 (40.0%) were fully adherent with all prescribed medications. Eighteen (45.0%) patients were partially adherent and 6 (15.0%) had none of the prescribed agents detected in their urine. Of 18 patients who were partially adherent, 5 (12.5%) were adherent with at least 5 medications, including chlorthalidone and the mineralocorticoid receptor antagonist, consistent with true RfHTN. Of patients identified as having apparent RfHTN, 52.5% were adherent with at least 5 antihypertensive medications, including chlorthalidone and a mineralocorticoid receptor antagonist, confirming true RfTHN. These findings validate RfHTN as a rare, but true phenotype of antihypertensive treatment failure.

Twenty-Four Hour Urine Testing and Prescriptions for Urinary Stone Disease-Related Medications in Veterans

BACKGROUND AND OBJECTIVES

Current guidelines recommend 24-hour urine testing in the evaluation and treatment of persons with high-risk urinary stone disease. However, how much clinicians use information from 24-hour urine testing to guide secondary prevention strategies is unknown. We sought to determine the degree to which clinicians initiate or continue stone disease-related medications in response to 24-hour urine testing.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined a national cohort of 130,489 patients with incident urinary stone disease in the Veterans Health Administration between 2007 and 2013 to determine whether prescription patterns for thiazide diuretics, alkali therapy, and allopurinol changed in response to 24-hour urine testing.

RESULTS

Stone formers who completed 24-hour urine testing (n=17,303; 13%) were significantly more likely to be prescribed thiazide diuretics, alkali therapy, and allopurinol compared with those who did not complete a 24-hour urine test (n=113,186; 87%). Prescription of thiazide diuretics increased in patients with hypercalciuria (9% absolute increase if urine calcium 201-400 mg/d; 21% absolute increase if urine calcium >400 mg/d, P<0.001). Prescription of alkali therapy increased in patients with hypocitraturia (24% absolute increase if urine citrate 201-400 mg/d; 34% absolute increase if urine citrate ≤200 mg/d, P<0.001). Prescription of allopurinol increased in patients with hyperuricosuria (18% absolute increase if urine uric acid >800 mg/d, P<0.001). Patients who had visited both a urologist and a nephrologist within 6 months of 24-hour urine testing were more likely to have been prescribed stone-related medications than patients who visited one, the other, or neither.

CONCLUSIONS

Clinicians adjust their treatment regimens in response to 24-hour urine testing by increasing the prescription of medications thought to reduce risk for urinary stone disease. Most patients who might benefit from targeted medications remain untreated.

Effectiveness of thiazides on serum and urinary calcium levels and bone mineral density in patients with osteoporosis: a systematic review and meta-analysis

Objective

Osteoporosis is the most common metabolic bone disease and a major public health problem worldwide. Thiazides are widely used as antihypertensive agents with good tolerability and efficacy. Furthermore, thiazides have long been regarded as candidates for the prevention of postmenopausal bone loss. However, there is insufficient evidence that thiazides have a sustained beneficial effect on preserving bone mass and preventing osteoporosis to date.

Materials and methods

We searched the PubMed, the Cochrane Library, and Embase in June 2018 for randomized controlled trials on the use of thiazides to treat osteoporosis. Continuous outcomes are presented as the standardized mean difference (SMD) and 95% CI. Furthermore, P-values <0.05 were considered significant.

Results

Five trials with 756 patients were randomly assigned in the five trials included in this meta-analysis. Serum calcium level was higher in the thiazide group than in the control group (SMD 0.33, 95% CI [0.16, 0.50]), and urinary calcium level was significantly lower in the thiazide group (SMD −0.35, 95% CI [−0.52, −0.17]). There was no significant difference in bone mineral density between the two groups (SMD 0.19, 95% CI [−0.16, 0.54]).

Conclusion

Thiazides might play a role in preserving bone mass and be effective in the prevention and treatment of osteoporosis. Future high-quality trials are needed to confirm our findings in the future.

Presentation, diagnostic assessment and surgical outcomes in primary hyperparathyroidism: a single centre's experience

OBJECTIVE

Primary hyperparathyroidism (PHPT) is a common reason for referral to endocrinology but the evidence base guiding assessment is limited. We evaluated the clinical presentation, assessment and subsequent management in PHPT.

DESIGN

Retrospective cohort study.

PATIENTS

PHPT assessed between 2006 - 2014 (n = 611) in a university hospital.

MEASUREMENTS

Symptoms, clinical features, biochemistry, neck radiology and surgical outcomes.

RESULTS

Fatigue (23.8%), polyuria (15.6%) and polydipsia (14.9%) were associated with PHPT biochemistry. Bone fracture was present in 16.4% but was not associated with biochemistry. A history of nephrolithiasis (10.0%) was associated only with younger age (P = 0.006) and male gender (P = 0.037). Thiazide diuretic discontinuation was not associated with any subsequent change in calcium (P = 0.514). Urine calcium creatinine clearance ratio (CCCR) was <0.01 in 18.2% of patients with confirmed PHPT. Older age (P < 0.001) and lower PTH (P = 0.043) were associated with failure to locate an adenoma on ultrasound (44.0% of scans). When an adenoma was identified on ultrasound the lateralization was correct in 94.5%. Non-curative surgery occurred in 8.2% and was greater in those requiring more than one neck imaging modality (OR 2.42, P = 0.035).

CONCLUSIONS

Clinical features associated with PHPT are not strongly related to biochemistry. Thiazide cessation does not appear to attenuate hypercalcaemia. PHPT remains the likeliest diagnosis in the presence of low CCCR. Ultrasound is highly discriminant when an adenoma is identified but surgical failure is more likely when more than one imaging modality is required.

Influence of West African Ethnicity and Gender on Beta-Cell Function and Insulin Sensitivity in Essential Hypertensives Treated with Hydrochlorothiazide and Hydrochlorothiazide-lisinopril Combination

OBJECTIVE

To assess the effects of hydrochlorothiazide (HCT) given alone and in combination with an angiotensin-converting enzyme inhibitor (ACEI) on beta-cell function in a negroid population to further explore possible ethnic differences in the effect of antihypertensive drugs on homeostasis model assessment - insulin resistance (HOMA-IR).

MATERIALS AND METHODS

A total of 80 newly diagnosed Nigerian essential hypertensive patients were assigned to receive either HCT 25 mg daily or both HCT and lisinopril (Lis; 25/10 mg daily) in an open-label study for 12 weeks. The treatment groups were well matched in clinical and demographic baseline features. Changes in HOMA-IR from baseline to end of study (week 12), fasting plasma glucose (FPG), serum potassium, serum insulin, and blood pressure over the same period were also evaluated.

RESULTS

After 12 weeks, mean delta HOMA-IR (and %) was higher in the HCT monotherapy group; although, this change did not reach statistical significance in both groups -0.1 ± 7.1, P = 0.538 (HCT) and 0.6 ± 4.2 P = 0.913 (HCT + Lis); an insignificant increase was observed in FPG and serum insulin in both groups, whereas serum potassium decreased in similar fashion. Blood pressure reduction was similar in both groups. Analysis of HOMA-IR change according to gender in response to HCT mono- or combination therapy with Lis showed no significant difference.

CONCLUSIONS

HCT monotherapy in hypertensive indigenous Nigerians, was not associated with worse metabolic effects when compared with combination therapy using Lis, an ACEI after 12 weeks. Low-dose thiazide diuretic as first-line antihypertensive medication may be safe in the short-term, further larger and long-term studies are needed to corroborate this finding.

[Differential diagnostic dilemmas after use of an out-of-date antihypertensive medication. Case report]

Hydrochlorothiazide became one of the most commonly prescribed first-line antihypertensive medication, though its use is often complicated with serious side-effects. A 66-year-old female patient with a history of hypertension had suffered a transient loss of consciousness, and referred to our cardiology unit with an ST-segment elevation and giant negative T-waves in V1-2 ECG leads, long QT-segment and elevated serum creatine-kinase (5392 U/L) and troponin I (4,357 ng/ml) levels. Acute myocardial infarction was not proven (later coronarography revealed preserved coronary circulation), but severe hyponatraemia and hypokalaemia was detected, explaining a possible symptomatic seizure, and which could be accounted for a 25 mg daily hydrochlorothiazide antihypertensive treatment and - as a precipitating insult - a one-week history of gastroenteritis. The case-report presents a unique differential diagnostic question where thiazide-induced hyponatraemia and hypokalaemia resulted in a clinical picture sharing some similarities with acute myocardial infarction. This case underlines the serious side-effects of an inappropriately used common antihypertensive medication. Orv. Hetil., 2017, 158(11), 426-431.

Acetazolamide and Hydrochlorothiazide Followed by Furosemide Versus Furosemide and Hydrochlorothiazide Followed by Furosemide for the Treatment of Adults With Nephrotic Edema: A Randomized Trial

BACKGROUND

Nephrotic edema is considered refractory if it does not respond to maximum or near-maximum doses of loop diuretics. This condition can be treated with loop diuretics and thiazides. However, animal studies show that the simultaneous downregulation of pendrin with acetazolamide and inhibition of the sodium-chloride cotransporter with hydrochlorothiazide generates significant diuresis, and furosemide administration following a pendrin inhibitor potentiates furosemide's diuretic effect. Therefore, we performed this study to compare the efficacy of acetazolamide and hydrochlorothiazide followed by furosemide versus furosemide and hydrochlorothiazide followed by furosemide for treatment of refractory nephrotic edema.

STUDY DESIGN

Randomized, double-blind, 2-arm, parallel trial.

SETTING & PARTICIPANTS

20 patients with refractory nephrotic edema despite treatment with 80mg of furosemide daily and creatinine clearance > 60mL/min.

INTERVENTION

Patients were randomly assigned to 2 groups: group 1 (n=10) received 250mg of acetazolamide and 50mg of hydrochlorothiazide daily and group 2 (n=10) received 40mg of furosemide and 50mg of hydrochlorothiazide daily for 1 week in phase 1. In phase 2, both groups received 40mg of furosemide daily for 2 weeks.

OUTCOMES

The primary outcome was absolute change in weight before and at the end of each phase.

MEASUREMENTS

Weight and 24-hour urine volume at baseline and the end of each phase.

RESULTS

The mean weight decrease was of significantly larger magnitude in group 1 compared with group 2 at the end of phase 1 (-1.4±0.52 [SD] vs -0.65±0.41kg; P=0.001) and phase 2 (-1.6±0.84 vs -0.5±0.47kg; P=0.005). The increase in 24-hour urine volume was also significantly higher in group 1 at the end of phase 2.

LIMITATIONS

Small sample size, short follow-up duration, and lack of serum bicarbonate and chloride measurement.

CONCLUSIONS

Acetazolamide and hydrochlorothiazide followed by furosemide is more effective than furosemide and hydrochlorothiazide followed by furosemide for the treatment of refractory nephrotic edema.

Intravenous Chlorothiazide Versus Enteral Metolazone to Augment Loop Diuretic Therapy in the Intensive Care Unit

BACKGROUND

In cases of loop diuretic resistance in the intensive care unit (ICU), recommendations for a specific second-line thiazide agent are lacking.

OBJECTIVE

To compare the effects of intravenous chlorothiazide (CTZ) and enteral metolazone (MET) on urine output (UOP) when added to furosemide monotherapy therapy in critically ill adults.

METHODS

This was a retrospective cohort study conducted in the medical, surgical, and cardiothoracic ICUs of a quaternary medical center. The primary outcome was change in UOP induced by the study interventions compared with furosemide alone. Secondary outcomes included onset of diuresis, eventual need for hemodialysis, and incidence of adverse events.

RESULTS

A total of 122 patients (58 in CTZ, 64 in MET) were included. When added to furosemide monotherapy, CTZ induced a greater change in UOP at 24 hours compared with MET (2405 vs 1646 mL, respectively; P = 0.01). CTZ also caused a more rapid dieresis: 1463 mL total UOP in the first 6 hours compared with 796 mL in the MET group ( P < 0.01). There were no differences found regarding ICU length of stay, need for renal replacement therapy, or survival to discharge. The CTZ arm required more potassium supplementation to maintain normokalemia (median 100 vs 57 mEq in MET; P = 0.02) and carried a higher cost (mean $97 vs $8, P < 0.01).

CONCLUSION

Both CTZ and MET induced significant increases in UOP. CTZ induced a greater and more rapid change and was associated with higher cost and greater need for potassium replacement. Randomized controlled trials are needed to establish whether a preferable thiazide diuretic exists in this setting.

Patterns and Correlates of Baseline Thiazide-Type Diuretic Prescription in the Systolic Blood Pressure Intervention Trial

Thiazides and thiazide-type diuretics are recommended as first-line agents for the treatment of hypertension, but contemporary information on their use in clinical practice is lacking. We examined patterns and correlates of thiazide prescription in a cross-sectional analysis of baseline data from participants enrolled in the Systolic Blood Pressure Intervention Trial (SPRINT). We examined baseline prescription of thiazides in 7582 participants receiving at least 1 antihypertensive medication by subgroup, and used log-binomial regression to calculate adjusted prevalence ratios for thiazide prescription (versus no thiazide). Forty-three percent of all participants were prescribed a thiazide at baseline, but among participants prescribed a single agent, the proportion was only 16%. The prevalence of thiazide prescription differed significantly by demographic factors, with younger participants, women, and blacks all having higher adjusted prevalence of thiazide prescription than other corresponding subgroups. Participants in the lowest category of kidney function (estimated glomerular filtration rate <30 mL/min per 1.73 m2) were half as likely to be prescribed a thiazide as participants with preserved kidney function. In conclusion, among persons with hypertension and heightened cardiovascular risk, we found that thiazide prescription varied significantly by demographics and kidney disease status, despite limited evidence about relative differences in effectiveness.

Continuous and long-term treatment is more important than dosage for the protective effect of thiazide use on bone metabolism and fracture risk

BACKGROUND

Data from observational studies have suggested that thiazide diuretics protect against fractures. Few studies have investigated time frames from initiation of treatment to fracture occurrence.

OBJECTIVE

To evaluate the time to spinal, hip, femur, wrist and upper extremity fracture occurrence before and after thiazide exposure.

METHODS

A matched retrospective cohort study of patient information from national Danish patient databases was conducted. Patients with reimbursed prescriptions for noncompounded thiazide diuretics with potassium supplementation (Anatomical Therapeutic Chemical classification system code C03AB) between 1996 and 2011 were matched with nonexposed control subjects by date of birth and gender. Weekly odds ratios (ORs) of fracture occurrence and total incidence rates (IRs) and incidence rate ratios (IRRs) of fracture risk were calculated for the periods before treatment initiation, weeks 1-42 and weeks 43-780.

RESULTS

A total of 1,602,141 'thiazide exposure periods' (46,8271 individuals) and 1,530,233 'nonexposure periods' (655,399 individuals) were included in the analysis. Thiazide use was associated with factors of increased de novo fracture risk. Weekly adjusted fracture risk between exposure and nonexposure was increased prior to commencing thiazide therapy, further increasing from weeks 1-42 weeks and then decreasing gradually from weeks 43-780. There was a decreasing trend in total age-adjusted risk during these periods: IRR [95% confidence interval 1.44 [1.42; 1.47], 1.27 [1.24; 1.29] and 1.14 [1.11; 1.18], respectively. Prescription patterns showed several treatment breaks amongst thiazide users.

CONCLUSIONS

It appears that thiazides reduce the background risk of fracture that is increased prior to commencing therapy. Long duration and continuity of thiazide exposure seems to be important to obtain this protective effect on fracture risk, but we have found in this study that this approach is not always used in clinical practice.

Risks associated with drug treatments for kidney stones

INTRODUCTION

Renal stones are one of the most painful medical conditions patients experience. For many they are also a recurrent problem. Fortunately, there are a number of drug therapies available to treat symptoms as well as prevent future stone formation.

AREAS COVERED

Herein, we review the most common drugs used in the treatment of renal stones, explaining the mechanism of action and potential side effects. Search of the Medline databases and relevant textbooks was conducted to obtain the relevant information. Further details were sourced from drug prescribing manuals. Recent studies of drug effectiveness are included as appropriate.

EXPERT OPINION

Recent controversies include medical expulsive therapy trials and complex role of urinary citrate in stone disease. Future directions in research will involve new medical therapies for stone prevention, for example new drugs for hyperoxaluria.

The role of calbindin-D28k on renal calcium and magnesium handling during treatment with loop and thiazide diuretics

Calbindin-D28k (CBD-28k) is a calcium binding protein located in the distal convoluted tubule (DCT) and plays an important role in active calcium transport in the kidney. Loop and thiazide diuretics affect renal Ca and Mg handling: both cause Mg wasting, but have opposite effects on Ca excretion as loop diuretics increase, but thiazides decrease, Ca excretion. To understand the role of CBD-28k in renal Ca and Mg handling in response to diuretics treatment, we investigated renal Ca and Mg excretion and gene expression of DCT Ca and Mg transport molecules in wild-type (WT) and CBD-28k knockout (KO) mice. Mice were treated with chlorothiazide (CTZ; 50 mg · kg(-1) · day(-1)) or furosemide (FSM; 30 mg · kg(-1) · day(-1)) for 3 days. To avoid volume depletion, salt was supplemented in the drinking water. Urine Ca excretion was reduced in WT, but not in KO mice, by CTZ. FSM induced similar hypercalciuria in both groups. DCT Ca transport molecules, including transient receptor potential vanilloid 5 (TRPV5), TRPV6, and CBD-9k, were upregulated by CTZ and FSM in WT, but not in KO mice. Urine Mg excretion was increased and transient receptor potential subfamily M, member 6 (TRPM6) was upregulated by both CTZ and FSM in WT and KO mice. In conclusion, CBD-28k plays an important role in gene expression of DCT Ca, but not Mg, transport molecules, which may be related to its being a Ca, but not a Mg, intracellular sensor. The lack of upregulation of DCT Ca transport molecules by thiazides in the KO mice indicates that the DCT Ca transport system is critical for Ca conservation by thiazides.

Severe hyponatremia associated with thiazide diuretic use

BACKGROUND

Thiazide diuretics are commonly used as first-line antihypertensive agents. Hyponatremia is a reported, though uncommon, complication of thiazide use. Although the exact mechanism of thiazide-induced hyponatremia (TIH) is unclear, it can be a significant cause of morbidity and mortality.

CASE REPORT

We report a 69-year-old man with generalized weakness beginning 2 weeks after starting hydrochlorothiazide (HCTZ). Evaluation revealed a serum sodium level of 120 mmol/L. The patient was admitted and successfully treated with free water restriction and discontinuation of the HCTZ. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Hyponatremia is an uncommon complication of thiazide diuretic use, which frequently presents with nonspecific symptoms. Identification of TIH is crucial to prevent its potentially life-threatening complications.

Engineering practice variation through provider agreement: a cluster-randomized feasibility trial

Purpose

Minimal-risk randomized trials that can be embedded in practice could facilitate learning health-care systems. A cluster-randomized design was proposed to compare treatment strategies by assigning clusters (eg, providers) to “favor” a particular drug, with providers retaining autonomy for specific patients. Patient informed consent might be waived, broadening inclusion. However, it is not known if providers will adhere to the assignment or whether institutional review boards will waive consent. We evaluated the feasibility of this trial design.

Subjects and methods

Agreeable providers were randomized to “favor” either hydrochlorothiazide or chlorthalidone when starting patients on thiazide-type therapy for hypertension. The assignment applied when the provider had already decided to start a thiazide, and providers could deviate from the strategy as needed. Prescriptions were aggregated to produce a provider strategy-adherence rate.

Results

All four institutional review boards waived documentation of patient consent. Providers (n=18) followed their assigned strategy for most of their new thiazide prescriptions (n=138 patients). In the “favor hydrochlorothiazide” group, there was 99% adherence to that strategy. In the “favor chlorthalidone” group, chlorthalidone comprised 77% of new thiazide starts, up from 1% in the pre-study period. When the assigned strategy was followed, dosing in the recommended range was 48% for hydrochlorothiazide (25–50 mg/day) and 100% for chlorthalidone (12.5–25.0 mg/day). Providers were motivated to participate by a desire to contribute to a comparative effectiveness study. A study promotional mug, provider information letter, and interactions with the site investigator were identified as most helpful in reminding providers of their study drug strategy.

Conclusion

Providers prescribed according to an assigned drug-choice strategy most of the time for the purpose of a comparative effectiveness study. This simple design could facilitate research participation and behavior change in non-research clinicians. Waiver of patient consent can broaden the representation of patients, providers, and settings.

Cyclophosphamide-induced symptomatic hyponatremia, a rare but severe side effect: a case report

Cyclophosphamide is commonly used in the treatment of malignant diseases. Symptomatic severe hyponatremia induced by low-dose cyclophosphamide is very uncommon worldwide. We report a case of severe symptomatic hyponatremia that developed in a female breast cancer patient following the first cycle of chemotherapy containing low-dose cyclophosphamide. Her laboratory test showed serum Na of 112 mmol/L. Her hyponatremia was initially treated with sodium bicarbonate. She completely recovered without neurological deficits after slow correction of the serum Na concentration. Although hyponatremia is a rare toxicity it should always be considered during the usage of cyclophosphamide, even if the dosage is low, especially with concurrent use of other medications that impair water excretion, like chlorthalidone. This report describes the first reported case of cyclophosphamide-induced hyponatremia in Qatar.

Thiazide diuretic prophylaxis for kidney stones and the risk of diabetes mellitus

PURPOSE

Thiazide diuretics used to treat hypertension are associated with a modest risk of diabetes mellitus. It is unknown if there is a similar risk with kidney stone prevention.

MATERIALS AND METHODS

We identified and validated incident stone formers in Olmsted County, Minnesota from 1984 to 2011 with manual review of medical records using the Rochester Epidemiology Project. The risk of diabetes mellitus after thiazide therapy was evaluated with and without multivariate adjustment for hypertension, age, gender, race, family history of stones, body mass index and number of stone events.

RESULTS

Among 2,350 incident stone formers with a median followup of 10 years, 332 (14%) were treated with thiazide diuretics at some point after the first stone event and 84 (3.6%) received the thiazide diuretic only for kidney stone prevention. Stone formers who received thiazide diuretics were more likely to be older, have hypertension, have higher body mass index and have more stone events. The incidence of diabetes mellitus at 10 years after the first stone event was 9.2% in the group that received thiazide diuretics vs 4.2% in those who did not (HR 2.91; 95% CI 2.02, 4.20). After multivariate adjustment the risk of diabetes mellitus was attenuated (HR 1.20; 95% CI 0.78, 1.83). The risk of diabetes mellitus among those receiving thiazide diuretics solely for kidney stones was further attenuated (multivariate adjusted HR 0.80; 95% CI 0.28, 2.23).

CONCLUSIONS

Thiazide diuretic use for kidney stone prophylaxis was not associated with a high risk of diabetes mellitus. Larger studies are needed to determine if there is a modest risk of diabetes mellitus with thiazide diuretics.

Descriptive study of clinical profile and benefit of therapy in childhood hypercalciuria

Clinical, biochemical, and ultrasonographic findings in 91 consecutive children presenting with hypercalciuria were analyzed along with the results of treatment to determine the clinical profile of hypercalciuria and its outcome. Hypercalciuria was common in children aged 1-5 years (39.6%), and hematuria was the most frequent symptom. There was no significant difference between 24-hour urinary calcium and random urinary calcium/creatinine ratio values between males and females. The random urinary calcium/creatinine ratio was found to be useful for screening and also for documenting the benefit of therapy. The children were essentially treated with thiazides, and the majority showed a good response, with a good overall outcome on follow-up.

Antihypertensive drugs and the risk of fall injuries: a systematic review and meta-analysis

OBJECTIVE

A meta-analysis of published studies was performed to determine whether administration of any of five antihypertensive drug classes (thiazide diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium channel blockers and β-blockers) affected the risk of fall injuries in the elderly (aged ≥60 years).

METHODS

Articles reporting the risk of fall injury in elderly people being treated with the five main classes of antihypertensive drugs were retrieved using MEDLINE®, EMBASE, SCOPUS® and the Cochrane Database. Trial eligibility and methodological quality were assessed before data extraction and analysed using odds ratios with 95% confidence intervals.

RESULTS

Sixty-two articles, included in two meta-analyses, were identified. These meta-analyses drew opposite conclusions about the role of antihypertensive drugs in fall injuries in the elderly. However, the present analysis did not reveal a clear association (or the lack of one) between antihypertensive drugs and risk of fall injuries.

CONCLUSIONS

There is no clear, statistically significant clinical precedent indicating that the use of any of the antihypertensive drugs considered here increases the risk of fall injuries in the elderly. Nonetheless, in following standard clinical guidelines for hypertension management, physicians need to be aware of the impact of drug therapies on fall injuries.

Thiazide-induced hyponatremia

The importance of thiazide-induced hyponatremia (TIH) is reemerging because thiazide diuretic prescription seems to be increasing after the guidelines recommending thiazides as first-line treatment of essential hypertension have been introduced. Thiazide diuretics act by inhibiting reabsorption of Na⁺ and Cl^- from the distal convoluted tubule by blocking the thiazide-sensitive Na⁺/Cl^- cotransporter. Thus, they inhibit electrolyte transport in the diluting segment and may impair urinary dilution in some vulnerable groups. Risk factors predisposing to TIH are old age, women, reduced body masses, and concurrent use of other medications that impair water excretion. While taking thiazides, the elderly may have a greater defect in water excretion after a water load compared with young subjects. Hyponatremia is usually induced within 2 weeks of starting the thiazide diuretic, but it can occur any time during thiazide therapy when subsequent contributory factors are complicated, such as reduction of renal function with aging, ingestion of other drugs that affect free water clearance, or changes in water or sodium intake. While some patients are volume depleted on presentation, most appear euvolemic. Notably serum levels of uric acid, creatinine and urea nitrogen are usually normal or low, suggestive of syndrome of inappropriate secretion of antidiuretic hormone. Despite numerous studies, the pathophysiological mechanisms underlying TIH are unclear. Although the traditional view is that diuretic-induced sodium or volume loss results in vasopressin-induced water retention, the following 3 main factors are implicated in TIH: stimulation of vasopressin secretion, reduced free-water clearance, and increased water intake. These factors will be discussed in this review.

Recently completed trials on the drug treatment of hypertension: comments on ALLHAT and ANBP-2

Recently the results of two important large-scale studies on hypertension management were published and intensely debated: ALLHAT and ANBP-2. In particular the ALLHAT study was discussed and subjected to criticism. The positive and negative aspects of this study are the subject of the present survey. ALLHAT has reemphasised the important role of thiazide diuretics in the treatment of hypertension. However, there should also be an important position for the various other well-known drugs such as β-blockers, ACE inhibitors, calcium antagonists and AT₁-blockers (sartans). The choice of the drug(s) to be prescribed is largely determined by the comorbidity, which occurs frequently in elderly hypertensives. Furthermore, combination therapy is applied more and more frequently.