Blood pressure drug therapy and electrolyte disturbances

Can the association between hypertension and physical activity be moderated by age?

Objectives

Physical inactivity, hypertension and non-communicable diseases are major public concerns across the globe. To our knowledge, there is a lack of research that has investigated the moderating effect of age on the relationship between hypertension and physical activity in developing countries. This study had two objectives: (1) investigating hypertension and sociodemographic factors associated with physical activity and (2) investigating whether age moderates the relationship between hypertension and physical activity.

Methods

Nationally representative data of Malaysia were used to generate cross-sectional evidence. The sample size was 2156 respondents. An ordered probit regression was utilized to assess factors associated with the practice of physical activity.

Results

Respondents aged 40-49 years with hypertension were 7.3% less likely to participate in high-level physical activity when compared to those without hypertension. The probability of having a low level of physical activity was 12.3% higher among hypertensive patients aged ≥60. Males, married individuals, less-educated adults, low-income earners, and individuals who were aware of their BMI, had a higher tendency to indulge in a highly active lifestyle than others.

Conclusion

The effect of hypertension on physical activity was moderated by age. Factors influencing physical activity levels among adults were income, gender, marital status, education, employment status, and BMI awareness.

Metals and Metal-Nanoparticles in Human Pathologies: From Exposure to Therapy

An increasing number of pathologies correlates with both toxic and essential metal ions dyshomeostasis. Next to known genetic disorders (e.g., Wilson's Disease and β-Thalassemia) other pathological states such as neurodegeneration and diabetes are characterized by an imbalance of essential metal ions. Metal ions can enter the human body from the surrounding environment in the form of free metal ions or metal-nanoparticles, and successively translocate to different tissues, where they are accumulated and develop distinct pathologies. There are no characteristic symptoms of metal intoxication, and the exact diagnosis is still difficult. In this review, we present metal-related pathologies with the most common onsets, biomarkers of metal intoxication, and proper techniques of metal qualitative and quantitative analysis. We discuss the possible role of drugs with metal-chelating ability in metal dyshomeostasis, and present recent advances in therapies of metal-related diseases.

An overview of diagnosis and management of drug-induced hypomagnesemia

Magnesium (Mg) is commonly addressed as the "forgotten ion" in medicine. Nonetheless, hypomagnesemia should be suspected in clinical practice in patients with relevant symptomatology and also be considered a predisposing factor for the development of other electrolyte disturbances. Furthermore, chronic hypomagnesemia has been associated with diabetes mellitus and cardiovascular disease. Hypomagnesemia as a consequence of drug therapy is relatively common, with the list of drugs inducing low serum Mg levels expanding. Culprit medications linked to hypomagnesemia include antibiotics (e.g. aminoglycosides, amphotericin B), diuretics, antineoplastic drugs (cisplatin and cetuximab), calcineurin inhibitors, and proton pump inhibitors. In recent years, the mechanisms of drug-induced hypomagnesemia have been unraveled through the discovery of key Mg transporters in the gut and kidney. This narrative review of available literature focuses on the pathogenetic mechanisms underlying drug-induced hypomagnesemia in order to increase the insight of clinicians toward early diagnosis and effective management.

Monotherapy with amlodipine or hydrochlorothiazide in patients with mild to moderate hypertension: Comparison of their efficacy and effects on electrolytes

Background

Amlodipine and hydrochlorothiazide (HCTZ) are commonly prescribed in Nigeria either as a monotherapy or in combination with other drugs. The present study was designed to investigate the antihypertensive efficacy of monotherapy with amlodipine or HCTZ and their effects on electrolyte profile in patients with mild to moderate hypertension.

Methods

A single-blind randomized clinical study was used; fifty patients newly diagnosed with mild to moderate hypertension (aged 33 to 60 years) were recruited and divided into two groups: amlodipine or hydrochlorothiazide each comprising of 25 subjects. The subjects received 5mg of amlodipine or 25mg of hydrochlorothiazide in their respective group once daily for 4 weeks. Blood pressure, serum and urine electrolytes were measured at baseline and weekly throughout the experiment.

Results

At the end of follow up, amlodipine reduced systolic and diastolic blood pressure significantly more (p<0.001) than HCTZ. At the end of follow up, blood pressure was reduced to normal in 80% of the subjects in amlodipine group compared to 50% in HCTZ. Amlodipine had no significant effect on electrolyte profile of subjects unlike HCTZ which significantly changed both their serum and urine electrolytes.

Conclusions

Monotherapy with amlodipine was more effective than HCTZ in black patients with mild to moderate hypertension and in addition maintained electrolyte balance.

Elevated High-Density Lipoprotein Cholesterol Is Associated with Hyponatremia in Hypertensive Patients

BACKGROUND

Recently, the Systolic Blood Pressure Intervention Trial (SPRINT) showed that intensive lowering of systolic blood pressure is beneficial, but is associated with more adverse events. Hyponatremia was notably more frequent in the intensive treatment group. Investigating its risk factors is crucial for preventing this complication. Our objective in this study was to identify risk factors for hyponatremia in the adult population.

METHODS

We investigated the baseline demographic, clinical, and laboratory data from the 9361 participants of SPRINT to identify the best predictors of hyponatremia (serum sodium ≤130 mEq/L), and adverse events, which could be attributed to hyponatremia, using machine learning and multivariable Cox proportional hazards models. We confirmed our results in the independent National Health and Nutrition Examination Survey (NHANES) cohort between the years 2005 and 2010 (16,501 participants).

RESULTS

Elevated baseline high-density lipoprotein cholesterol (HDL-C) was a strong predictor of future hyponatremia. Multivariable Cox regression showed hyponatremia events to be significantly increased for SPRINT participants with baseline HDL-C levels in the highest quintile (hazard ratio [HR] 2.8; 95% confidence interval [CI], 2.2-3.7; P <.001), and were also associated with treatment-related serious adverse events (HR 1.6; 95% CI, 1.3-2.1; P <.001). We confirmed the association between HDL-C and hyponatremia in the NHANES cohort (HR 2.5; 95% CI, 1.7-3.7; P <.001).

CONCLUSIONS

Elevated HDL-C (≥62 mg/dL) is a risk factor for hyponatremia. Thus, hypertensive patients with elevated HDL-C should be closely monitored for hyponatremia when treated for hypertension.

Elevated baseline potassium level within reference range is associated with worse clinical outcomes in hospitalised patients

The clinical significance of elevated baseline serum potassium (K⁺) levels in hospitalised patients is rarely described. Hence, we performed a retrospective study assessing the significance of elevated K⁺ levels in a one-year admission cohort. Adult patients without hypokalaemia or end-stage renal disease were included. Adverse outcomes were all-cause mortality, hospital-acquired acute kidney injury, and events of arrhythmia. In total, 17,777 patients were included in the study cohort, and a significant difference (P < 0.001) was observed in mortality according to baseline serum K⁺ levels. The adjusted hazard ratios (HRs) and associated 95% confidence intervals (CIs) of all-cause mortality for K⁺ levels above the reference range of 3.6–4.0 mmol/L were as follows: 4.1–4.5 mmol/L, adjusted HR 1.075 (95% CI 0.981–1.180); 4.6–5.0 mmol/L, adjusted HR 1.261 (1.105–1.439); 5.1–5.5 mmol/L, adjusted HR 1.310 (1.009–1.700); >5.5 mmol/L, adjusted HR 2.119 (1.532–2.930). Moreover, the risks of in-hospital acute kidney injury and arrhythmia were higher in patients with serum K⁺ levels above 4.0 mmol/L and 5.5 mmol/L, respectively. In conclusion, increased serum K⁺ levels, including mild elevations may be related to worse prognosis. Close monitoring and prompt correction of underlying causes or hyperkalaemia itself is warranted for admitted patients.

The effect of admission serum potassium levels on in-hospital and long-term mortality in type A acute aortic dissection

BACKGROUND

Mild fluctuations in serum potassium (K⁺) levels are related to the prognosis of cardiovascular disease. This study aimed to determine the effect of admission serum potassium levels on in-hospital and long-term mortality in patients with Stanford type A acute aortic dissection (AAD).

MATERIALS AND METHODS

A total of 588 consecutive patients with type A AAD were enrolled, and they were grouped according to admission serum potassium level: <3.5, 3.5 to <4.0, 4.0 to <4.5, 4.5 to <5.0, and ≥5.0mmol/L. Clinical outcomes were in-hospital death and long-term all-cause mortality.

RESULTS

The in-hospital and long-term all-cause mortality rates were 10.7% and 16.3%, respectively. A U-shaped relationship was observed between admission serum potassium levels and both in-hospital death and long-term mortality. Univariate Cox regression identified potassium levels outside the interval of <3.5 to 4.5mmol/L to be a risk factor for both in-hospital and long-term death. After adjusting for age, gender, surgery and other risk factors, potassium levels outside the interval of <3.5 to 4.5mmol/L still had a significant association with long-term death [hazard ratio (HR)=1.72, 95% confidence interval (95% CI): 1.07-2.74, P=0.024]. Surgical intervention was the main protective factor associated with both in-hospital (HR=0.01, 95% CI 0.01-0.06, P<0.001) and long-term survival (HR=0.06, 95% CI 0.03-0.12, P<0.001).

CONCLUSIONS

Among patients with Stanford type A AAD, admission serum potassium levels other than 3.5 to 4.5mmol/L might be associated with an increased risk of in-hospital death and long-term mortality.

Carvedilol-induced hyperkalemia in a patient with chronic kidney disease

A 69-year-old male was admitted to the hospital with a chief complaint of abdominal pain, nausea, and vomiting. He had an extensive past medical history, including diabetes mellitus type 2 and chronic kidney disease stage III. Prior to admission, the patient was taking carvedilol 3.125 mg twice daily with no abnormality in his serum potassium. During hospitalization, his carvedilol was increased to 6.25 mg twice daily. The patient's serum potassium then rose from 4.8 to 6.7 mEq/L, with no improvement following administration of sodium polystyrene sulfonate. Nephrology concluded the carvedilol could be contributing to the hyperkalemia. The dose was decreased back to 3.125 mg twice daily, leading to the potassium normalizing to 4.4 mEq/L. The reported incidence of beta-blocker-induced hyperkalemia is less than 5%. A literature search revealed several cases of beta-blocker-induced hyperkalemia, but to the authors' knowledge, this is the first case describing carvedilol specifically. Utilization of the Naranjo probability scale indicated a possible probability that the carvediol was the cause.

Diabetes mellitus and electrolyte disorders

Diabetic patients frequently develop a constellation of electrolyte disorders. These disturbances are particularly common in decompensated diabetics, especially in the context of diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. These patients are markedly potassium-, magnesium- and phosphate-depleted. Diabetes mellitus (DM) is linked to both hypo- and hyper-natremia reflecting the coexistence of hyperglycemia-related mechanisms, which tend to change serum sodium to opposite directions. The most important causal factor of chronic hyperkalemia in diabetic individuals is the syndrome of hyporeninemic hypoaldosteronism. Impaired renal function, potassium-sparing drugs, hypertonicity and insulin deficiency are also involved in the development of hyperkalemia. This article provides an overview of the electrolyte disturbances occurring in DM and describes the underlying mechanisms. This insight should pave the way for pathophysiology-directed therapy, thus contributing to the avoidance of the several deleterious effects associated with electrolyte disorders and their treatment.

Hyponatremia in patients with heart failure

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Pharmaco-nutrient interactions - a systematic review of zinc and antihypertensive therapy

BACKGROUND

Antihypertensive medicines are to known to cause diverse disturbances to electrolyte homeostasis; however, their potential to affect zinc is less well known. The primary aim was to explore whether antihypertensive medicines have the potential to affect zinc status.

METHODS

A review of electronic databases was undertaken. Full-length English language articles describing clinical trials involving antihypertensive medicines and reporting on zinc measurements were reviewed.

RESULTS

Eight eligible studies were identified which involved the use of ACE inhibitors, thiazide diuretics, beta blockers, or ARB drugs of which five included a control group Studies used urinary zinc excretion, plasma zinc levels or erythrocyte zinc as key measures of zinc status. Studies reported increased urinary zinc losses for captopril (from 50 mg/day), enalapril (20 mg/day), losartan (50 mg/day), losartan (50 mg/day) together with hydrochlorothiazide (12.5 mg/day), captopril (75 mg/day) together with frusemide (40 mg/day) and stand-alone hydrochlorothiazide (25 mg/day). Serum levels of zinc decreased with captopril (50-150 mg/day), verapamil (240 mg/day), atenolol (50-150 mg/day) and the combination of losartan (50 mg/day) and hydrochlorothiazide (12.5 mg/day), eryrthrocyte levels decreased with use of valsartan (80 mg/day) and in some studies for captopril, but not for metoprolol (100 mg/day), atenolol (50-150 mg/day), verapamil (240 mg/day), doxazosin (4 mg/day) or amlodipine 10 mg/day). Major limitations were that most studies were small and did not report on dietary zinc intake.

CONCLUSION

The available evidence suggests that use of ACE inhibitors and angiotensin 2 receptor antagonists or thiazide diuretics have the potential to reduce zinc levels in hypertensive patients. Additional research using larger participant numbers and accounting for dietary zinc intakes are required.

Hyponatremia in geriatric inhospital patients: effects on results of a comprehensive geriatric assessment

OBJECTIVES

To study whether geriatric patients with mild-to-moderate hyponatremia (≤131 mmol/l) reveal different outcomes in structured tests for functional and cognitive impairments, depression and malnutrition compared to normonatremic patients.

DESIGN

Single-center, retrospective case control study.

SETTING

The study was conducted in a Geriatric Evaluation and Management Unit of a Department for Geriatrics and Internal Medicine.

METHODS AND PARTICIPANTS

We included 2,880 elderly patients (75.6% female, mean age 78.6 ± 6.98 years), consecutively admitted to the GEMU primarily or from another hospital or emergency department. Results were compared between a group of 129 patients with mild-to-moderate hyponatremia (118-131 mmol/l) and an age- and sex-matched control group of 129 patients with normal serum sodium values (>135 mmol/l). To assess functional and cognitive status, depression and malnutrition we used standardized tests of a geriatric assessment.

RESULTS

16.7% (n = 477) of the total 2,880 patients were hyponatremic (≤135 mmol/l), 4.5% (n = 129) revealed moderate hyponatremia. Compared to the control group, these patients had significantly worse results in all tests of the Geriatric Assessment, including Activities of Daily Living, Mini Mental State Examination, Clock Completion Test, Geriatric Depression Score, Tinetti Mobility Test and the Timed Up&Go Test and the Mini Nutritional Assessment. Comorbidities were assessed by the Charlson Comorbidity Index and the Cumulative Illness Rating Scale with no significant difference between the two groups. The hyponatremic patients received significantly more medications than the normonatremic control group, but we could not find a significant difference with respect to the use of a distinct single drug therapy.

CONCLUSION

We were able to demonstrate that geriatric patients with mild-to-moderate hyponatremia revealed a significantly worse outcome in all standardized tests of the geriatric assessment compared to a normonatremic control group. Serum sodium levels should therefore be considered when interpreting common tests of geriatric assessment.

Biochemical monitoring of patients treated with antihypertensive therapy for adverse drug reactions: a systematic review

Biochemical monitoring of patients treated with antihypertensive therapy is recommended in order to identify potential adverse reactions to treatment. We aimed to review the literature investigating the nature of biochemical monitoring in adults treated in primary care with antihypertensive drugs. Specifically, we wished to establish (i) the proportion of patients with biochemical baseline testing prior to the initiation of antihypertensive therapy; (ii) the proportion of patients with biochemical monitoring after initiation of antihypertensive therapy; (iii) the patient characteristics associated with biochemical monitoring; (iv) the frequency of biochemical monitoring after the initiation of antihypertensive therapy; and (v) the relationship, if any, between biochemical monitoring and adverse patient outcomes. We searched MEDLINE, EMBASE and Google Scholar from 1948 to 31 December 2010 using a combination of text words and search terms. Retrospective and prospective cohort studies, cross-sectional studies, randomized controlled trials or quasi-randomized controlled trials, and audits of current clinical practice were included. Clinical trials, case reports and case series were excluded. Studies were included if they provided data on the proportion of patients treated with antihypertensive therapy in primary care who had any biochemical monitoring before or after the initiation of therapy. In total, 15 studies were included in our review, which used a wide variety of definitions of monitoring prior to and after the initiation of antihypertensive therapy. From 17% to 81% of patients treated with antihypertensive drugs had a baseline biochemical test and from 20% to 79% had any follow-up monitoring. In only 7 of the 12 studies that examined follow-up monitoring did more than half of the patients have any monitoring. Overall, this systematic review provides evidence that monitoring as recommended by published guidelines is not commonly undertaken. Only two studies were identified that examined patients with both baseline testing and follow-up monitoring. Omission of one or the other limits the ability to analyse the effect of treatment on electrolyte concentrations or renal function. There is limited research on the patient factors associated with monitoring and further work is required to determine the impact of monitoring on adverse patient outcomes. Important barriers to effective monitoring exist and this review emphasizes that these have not yet been overcome.

Pharmacogenetic association of hypertension candidate genes with fasting glucose in the GenHAT Study

BACKGROUND

Several clinical studies report increased risk of diabetes mellitus with pharmacologic treatment for hypertension (HTN). HTN genes may modify glycemic response to antihypertensive treatment.

METHOD

The current study examined the association of 24 single nucleotide polymorphisms (SNPs) in 11 HTN candidate genes with fasting glucose measured at 2, 4, and 6 years after treatment initiation. The study sample included participants free of diabetes at baseline in the Genetics of Hypertension Associated Treatment (GenHAT) study (N = 9309). GenHAT participants were randomized to receive treatment with a diuretic (chlorthalidone), calcium channel blocker (amlodipine), or angiotensin-converting enzyme (ACE) inhibitor (lisinopril). Mixed models for repeated measures were employed to test for gene and pharmacogenetic associations with fasting glucose during follow-up.

RESULTS

Fasting glucose at year 2 increased on average 6.8, 4.8 and 3.0 mg/dl from baseline in the chlorthalidone, amlodipine and lisinopril groups, respectively. Carrying the I allele (rs1799752) of the ACE I/D polymorphism was associated with lower fasting glucose levels (P = 0.02). Additionally, an ACE promoter polymorphism (-262, rs4291) was associated with lower fasting glucose for the model AA/AT vs. TT, which remained significant after correction for multiple testing (P = 0.001). Finally, a SNP in the α-subunit of the amiloride-sensitive epithelial sodium channel (SCNN1A, rs2228576) modified the association of amlodipine vs. chlorthalidone treatment with fasting glucose (P < 0.001).

CONCLUSION

Further examination of these genes and their relationships with cardiometabolic disease could foster development of pharmacogenetic guidelines aimed to prevent increases in fasting glucose during antihypertensive treatment.

Diuretics in clinical practice. Part II: electrolyte and acid-base disorders complicating diuretic therapy

IMPORTANCE OF THE FIELD

As with all potent therapeutic agents, the use of diuretic compounds has been linked with several adverse effects that may reduce quality of life and patient compliance and, in some cases, may be associated with considerable morbidity and mortality. Among the various types of adverse effects, disturbances of electrolyte and acid-base balance are perhaps the most common, and some of them are the aetiological factors of other side effects (i.e., hypokalaemia causing ventricular arrhythmias or glucose intolerance). The mechanism and site of action and, therefore, the pharmacological effects of each diuretic class largely determine the specific electrolyte or acid-base abnormalities that will accompany the use of each diuretic agent.

AREAS COVERED IN THE REVIEW

This article reviews the major electrolyte disturbances (hypokalaemia, hyperkalaemia, hyponatraemia, disorders of magnesium and calcium balance), as well as the acid-base abnormalities complicating the use of the various diuretic agents.

WHAT THE READER WILL GAIN

The reader will gain insights into the pathogenesis of the diuretic-induced electrolyte and acid-base disorders together with considerations for their prevention and treatment.

TAKE HOME MESSAGE

Knowledge of the pharmacologic properties of each diuretic class and appropriate monitoring of patients under diuretic treatment represent the most important strategies to prevent the development of diuretic-related adverse events and their consequences.

Refeeding syndrome: treatment considerations based on collective analysis of literature case reports

Refeeding syndrome (RFS) represents a group of clinical findings that occur in severely malnourished individuals undergoing nutritional support. Cardiac arrhythmias, multisystem organ dysfunction, and death are the most severe symptoms observed. As the cachectic body attempts to reverse its adaptation to the starved state in response to the nutritional load, symptoms result from fluid and electrolyte imbalances, with hypophosphatemia playing a central role. Because guidelines for feeding the malnourished patient at risk for refeeding syndrome is scarce, we have provided management recommendations based on the knowledge derived from a collection of reported English literature cases of the RFS. A MEDLINE search using keywords including "refeeding syndrome," "RFS," and "refeeding hypophosphatemia" was performed. References from initial cases were utilized for more literature on the subject. We have emphasized the continued importance of managing patients at risk for RFS, compared how management of the severely malnourished patients have evolved over time, and provided comprehensive clinical guidelines based on the sum of experience documented in the case reports for the purpose of supplementing the guidelines available. Based on our review, the most effective means of preventing or treating RFS were the following: recognizing the patients at risk; providing adequate electrolyte, vitamin, and micronutrient supplementation; careful fluid resuscitation; cautious and gradual energy restoration; and monitoring of critical laboratory indices.

Severe hyponatraemia during therapy with ramipril

An older patient who was being treated with ramipril, chlorpromazine and aspirin presented with hypotension and serum sodium of 119 mmol/litre. The patient was treated with intravenous saline and all drug therapy was stopped. Serum sodium rose following fluid therapy. Ramipril was restarted as the patient's blood pressure increased. Serum sodium dropped to 112 mmol/litre. The patient's thyroid and adrenal functions were within normal limits, as were liver function tests and C-reactive protein. The hyponatraemia corrected when the patient was placed on fluid restriction and treatment with ramipril stopped.