Hyperkalemia in hospitalized patients

Risk of Serious Adverse Gastrointestinal Events with Potassium Binders in Hospitalized Patients: A National Study

BACKGROUND

Concerns about serious adverse gastrointestinal (GI) events with sodium polystyrene sulfonate (SPS) led to development of two new potassium binders, patiromer and sodium zirconium cyclosilicate (SZC), for treatment of hyperkalemia.

OBJECTIVE

To compare risk of intestinal ischemia/thrombosis or other serious GI events associated with SPS, patiromer, or SZC in hospitalized patients.

DESIGN

Retrospective cohort study.

PARTICIPANTS

National sample of 3,144,960 veterans hospitalized 2016-2022 in the U.S. Department of Veterans Affairs Healthcare System.

MAIN MEASURES

Demographics, comorbidities, medications and outcomes were ascertained from the VA Corporate Data Warehouse. Exposures were SPS, patiromer, SZC. Outcomes were 30-day intestinal ischemia/thrombosis, and a composite of intestinal ischemia/thrombosis, peptic ulcer/perforation or bowel resection/ostomy.

KEY RESULTS

Potassium binders were used during 39,270 (1.3%) hospitalizations: SPS = 30,040 (1.0%), patiromer = 3,750 (0.1%), and SZC = 5,520 (0.2%). Intestinal ischemia/thrombosis occurred with 106/30,040 (0.4%) SPS, 12/3750 (0.3%) patiromer and 24/5520 (0.4%) SZC, vs. 6998/3,105,650 (0.2%) without potassium binder. Adjusted odds ratios (aOR) were 1.40 [95% CI, 1.16 to 1.69] with SPS, 1.36 [CI, 0.79 to 2.36] with patiromer, and 1.78 [CI, 1.21 to 2.63] with SZC exposures. Composite GI adverse events occurred with 754/30,040 (2.5%) SPS, 96/3750 (2.6%) patiromer, 2.6% SZC, vs. 144/5520 (2.4%) without binder; aOR were 1.00 [CI, 0.94 to 1.08] with SPS, 1.08 [CI, 0.89 to 1.32] with patiromer, and 1.08 [CI, 0.93 to 1.27] with SZC exposures. No statistical difference in intestinal ischemia/thrombosis between each new agent and SPS was seen (p = 0.274 for SPS vs. SZC; p = 0.916 for SPS vs. patiromer).

CONCLUSION

Risk of intestinal ischemia/thrombosis or other serious adverse GI events was low and did not differ across three potassium-binding drugs.

Distinct phenotypes of hospitalized patients with hyperkalemia by machine learning consensus clustering and associated mortality risks

BACKGROUND

Hospitalized patients with hyperkalemia are heterogeneous, and cluster approaches may identify specific homogenous groups. This study aimed to cluster patients with hyperkalemia on admission using unsupervised machine learning (ML) consensus clustering approach, and to compare characteristics and outcomes among these distinct clusters.

METHODS

Consensus cluster analysis was performed in 5133 hospitalized adult patients with admission hyperkalemia, based on available clinical and laboratory data. The standardized mean difference was used to identify each cluster's key clinical features. The association of hyperkalemia clusters with hospital and 1-year mortality was assessed using logistic and Cox proportional hazard regression.

RESULTS

Three distinct clusters of hyperkalemia patients were identified using consensus cluster analysis: 1661 (32%) in cluster 1, 2455 (48%) in cluster 2 and 1017 (20%) in cluster 3. Cluster 1 was mainly characterized by older age, higher serum chloride and acute kidney injury (AKI), but lower estimated glomerular filtration rate (eGFR), serum bicarbonate and hemoglobin. Cluster 2 was mainly characterized by higher eGFR, serum bicarbonate and hemoglobin, but lower comorbidity burden, serum potassium and AKI. Cluster 3 was mainly characterized by higher comorbidity burden, particularly diabetes and end-stage kidney disease, AKI, serum potassium, anion gap, but lower eGFR, serum sodium, chloride and bicarbonate. Hospital and 1-year mortality risk was significantly different among the three identified clusters, with highest mortality in cluster 3, followed by cluster 1 and then cluster 2.

CONCLUSION

In a heterogeneous cohort of hyperkalemia patients, three distinct clusters were identified using unsupervised ML. These three clusters had different clinical characteristics and outcomes.

Correlation between Hyperkalemia and the Duration of Several Hospitalizations in Patients with Chronic Kidney Disease

(1) Background: This observational study aimed to verify the association between serum potassium levels and hospitalization days in patients with chronic kidney disease in a follow up of nine months. (2) Methods: Patients with chronic kidney disease were divided into group A (180 patients, potassium ≤ 5.1 mEq/L) and B (90 patients, potassium > 5.1 mEq/L). Student's t-test, Mann-Whitney test, Pearson's Chi-Square test, Pearson/Spearman's correlation test and linear regression test were performed in the entire sample and in stage-G4/5 subsample. (3) Results: Groups A and B differed for estimated glomerular filtration rate (eGFR) (34.89 (IQR, 16.24-57.98) vs. 19.8 (IQR, 10.50-32.50) mL/min/1.73 m²; p < 0.0001), hemoglobin (11.64 ± 2.20 vs. 10.97 ± 2.19 g/dL, p = 0.048), sum of hospitalization days (8 (IQR, 6-10) vs. 11 (IQR, 7-15) days; p < 0.0001) and use of angiotensin II receptor blockers (40.2% vs. 53.3%; p = 0.010). Considering patients with eGFR 6-30 mL/min/1.73 m², differences in the sum of hospitalization days were confirmed. Multivariable regression analysis showed that hyperkalemia is an independent risk factor of increased hospital length. In stage G4-G5, regression analysis showed that hyperkalemia is the only independent risk factor (β = 2.93, 95% confidence interval, 0.077-5.794, p = 0.044). (4) Conclusions: We observed significantly greater odds of increased length of hospital stay among patients with higher potassium, mostly in stages G4-G5 chronic kidney disease.

Clinical outcomes associated with the emergency treatment of hyperkalaemia with intravenous insulin-dextrose

BACKGROUND

Hyperkalaemia occurs in up to 10% of hospital admissions but its treatment in the emergency setting is inconsistent.

OBJECTIVES

To describe the emergency management of hyperkalaemia in adults with insulin-dextrose (IDex) and to explore clinical outcomes associated with IDex treatment.

DESIGN AND SETTING

Cohort study using comprehensive electronic health records of all emergency admissions to a large university hospital in the United Kingdom between April 2015 and August 2018.

PARTICIPANTS

Adult patients aged ≥16 years with at least one emergency admission and one blood potassium result during the study period.

MAIN OUTCOMES AND MEASURES

Emergency hyperkalaemia treatment was evaluated including the requirement for re-treatment with IDex, episodes of glucose dysregulation, intensive care (ICU) admission and length of hospital stay. Associations with hyperkalaemia, adverse events and IDex treatment were explored by logistic regression.

RESULTS

Amongst 211,993 patients attending the Emergency Department (ED) we identified 11,107 hyperkalaemic adult patients, of whom 1,284 were treated with IDex. Multiple doses were required in 542 patients (42.2%). Hypoglycaemia (plasma glucose < 4 mmol/L) occurred in 249 patients (19.4%) within 6 hours of IDex. Repeated doses were associated with an increased risk of hypoglycaemia (OR 2.94, 95% CI 2.20 to 3.93) compared to patients receiving a single dose, which, after adjustment was also associated with an increased risk of death (OR 1.56, 95% CI 1.16 to 2.09) during the study period. Patients who received multiple doses of IDex (OR 2.2, 95% CI 1.6-3.1) and those who received a dose of insulin above the guideline recommended limit (OR 5.6 3.1-10.3) were more likely to be admitted to ICU following IDex than those who received a single dose or the guideline recommended dose of insulin.

CONCLUSIONS AND RELEVANCE

This study provides novel insight into the emergency management of hyperkalaemia in a large population, demonstrates the high risk of hypoglycaemia and highlights the urgent need for an improved, evidence-based approach to the emergency management of hyperkalaemia.

Epidemiology, prognosis and management of potassium disorders in Covid-19

Coronavirus disease (Covid-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently the largest health crisis facing most countries. Several factors have been linked with a poor prognosis for this disease, including demographic factors, pre-existing comorbidities and laboratory parameters such as white blood cell count, D-dimer, C-reactive protein, albumin, lactate dehydrogenase, creatinine and electrolytes. Electrolyte abnormalities particularly potassium disorders are common among Covid-19 patients. Based on our pooled analysis, hypokalemia and hyperkalemia occur in 24.3% and 4.15% of Covid-19 patients, respectively. Potassium level deviation from the normal range may increase the chances of unfavorable outcomes and even death. Therefore, this article reviewed the epidemiology of potassium disorders and explained how hypokalemia and hyperkalemia are capable of deteriorating cardiac outcomes and the prognosis of Covid-19 for infected patients. The article finishes by highlighting some important considerations in the management of hypokalemia and hyperkalemia in these patients.

The pharmacotherapeutic management of hyperkalemia in patients with cardiovascular disease

Introduction: Patients with cardiovascular diseases (CVD) are at increased risk of hyperkalemia, particularly when treated with renin-angiotensin-aldosterone inhibitors (RAASIs). Because the occurrence or fear of hyperkalemia, RAASIs are frequently down-titrated or discontinued in patients with CVD, with consequent worse outcomes than patients who remain on maximum doses.Areas covered: This article reviews potassium homeostasis, epidemiology, risk factors, and outcomes of hyperkalemia, and efficacy and safety of the drugs used for acute and chronic treatment of hyperkalemia. A literature search was carried out using the PubMed and guidelines for the management of hyperkalemia.Expert opinion: The emergency treatment of hyperkalemia is not supported by high-quality evidence and clinical trials did not report drug effects on clinical outcomes. Two potassium binders, patiromer and sodium zirconium cyclosilicate, represent a new approach in the treatment of chronic hyperkalemia as they may allow the titration and maintenance of guidelines-recommended doses of RAASIs in patients with CVD who otherwise would not tolerate them due to the risk of hyperkalemia.Further studies are needed to evaluate the safety and efficacy of drug therapy and support the development of guidelines for acute and chronic hyperkalemia.

Iatrogenic hypoglycaemia following glucose-insulin infusions for the treatment of hyperkalaemia

OBJECTIVES

To study the incidence of, and risk factors for, iatrogenic hypoglycaemia following GwI infusion in our institution.

CONTEXT

Hyperkalaemia is a life-threatening biochemical abnormality. Glucose-with-insulin (GwI) infusions form standard management, but risk iatrogenic hypoglycaemia (glucose ≤ 3.9 mmol/L). Recently updated UK guidelines include an additional glucose infusion in patients with pretreatment capillary blood glucose (CBG) < 7.0 mmol/L.

DESIGN

Retrospective analysis of outcomes for GwI infusions prescribed for hyperkalaemia from 1 January to 28 February 2019, extracted from the Newcastle upon Tyne Hospitals NHS Foundation Trust electronic platform (eRecord).

PARTICIPANTS

132 patients received 228 GwI infusions for hyperkalaemia.

MAIN OUTCOME MEASURES

Incidence, severity and time to onset of hypoglycaemia.

RESULTS

Hypoglycaemia incidence was 11.8%. At least 1 hypoglycaemic episode occurred in 18.2% of patients with 6.8% having at least 1 episode of severe hypoglycaemia (< 3.0 mmol/L). Most episodes (77.8%) occurred within 3 h of treatment. Lower pretreatment CBG (5.9 mmol/L [4.1 mmol/L-11.2 mmol/L], versus 7.6 mmol/L [3.7 mmol/L-31.3 mmol/L], P = .000) was associated with hypoglycaemia risk. A diagnosis of type 2 diabetes and treatment for hyperkalaemia within the previous 24 h were negatively associated.

CONCLUSIONS

Within our inpatient population, around 1 in 8 GwI infusions delivered as treatment for hyperkalaemia resulted in iatrogenic hypoglycaemia. Higher pretreatment CBG and a diagnosis of type 2 diabetes were protective, irrespective of renal function. Our findings support the immediate change to current management, either with additional glucose infusions or by using glucose-only infusions in patients without diabetes. These approaches should be compared via a prospective randomized study.

Type IV RTA in Chronic Adrenal Insufficiency and Concomitant Lisinopril Treatment

Type IV renal tubular acidosis (RTA) is the only RTA characterized by hyperkalemia, and it is caused by a true aldosterone deficiency or renal tubular aldosterone hyporesponsiveness. It is frequent among hospitalized patients as it is related to type 2 diabetes mellitus (T2DM) and common medications such as ACE-inhibitors (ACE-is) and trimethoprim-sulfamethoxazole (TMP-SMX). Drug-induced RTA commonly manifests in patients with predisposing conditions such as mild renal insufficiency and certain pharmacological therapies. ACE-i use and chronic adrenal insufficiency (cAI) are other significant risk factors. Chronic ACTH suppression is thought to induce global adrenal atrophy, including the zona glomerulosa, thus affecting aldosterone secretion as well. Furthermore, in the setting of cAI, treatment with ACE-is further suppresses aldosterone production. This case report describes a patient with cAI secondary to corticosteroid use for years who developed type IV RTA in the setting of lisinopril use. Potassium (K) elevation persisted despite removing underlying conditions and metabolic acidosis correction. The patient required long-term treatment with mineralocorticoids in addition to sodium bicarbonate to maintain normal K levels and acid-base status. Mineralocorticoid administration is a second-line treatment for type IV RTA, but it might be necessary for a subgroup of high-risk patients. In fact, it is important to consider patients with chronic adrenal insufficiency and on ACE-is treatment at increased risk for refractory hyperkalemia in the setting of type IV RTA. Indeed, this subgroup of patients can have severe hypoaldosteronism.

Hyperkalemia Among Hospitalized Patients and Association Between Duration of Hyperkalemia and Outcomes

Background Hyperkalemia is a serious life-threatening condition that leads to significant morbidity and mortality. Objectives The aim of this study is to investigate the association between the duration and outcomes in patients hospitalized with hyperkalemia, as well as associated risk factors and drug-induced hyperkalemia. Methods A three-year retrospective chart review study was conducted at a tertiary hospital at King Abdulaziz Medical City, Riyadh, Saudi Arabia, between January 2016 and April 2019. We included all hospitalized adults and patients with hyperkalemia. Pediatric patients and dialysis patients with end-stage renal failure were excluded. Results Out of a total of 300 hospitalized patients who were screened for hyperkalemia, only 142 patients were included. The majority of cases were males (56.3%), whereas 43.7% were females. Most patients were above 55 years old. Regarding comorbidities in patients with hyperkalemia, most of them suffered from high blood pressure or diabetes. The mean serum potassium value was 5.7 ± 0.51 mEq. The most frequent medications used in the study population were azole antifungal medication followed by nonsteroidal anti-inflammatory drugs, beta-blockers, and angiotensin-converting enzyme inhibitors. Around 54 patients were not treated with medication and were monitored for spontaneous correction of hyperkalemia. Insulin was the most used medication for the treatment of hyperkalemia. The mean duration for the resolution of hyperkalemia was 12 ±9.4 hours. Out of 142 patients, only 10 (7%) patients died with hyperkalemia. Conclusions Hospitalized patients are at risk of hyperkalemia. In our study, we found that patients who had hyperkalemia were significantly likely to have acute kidney injury or cardiovascular diseases, and azole antifungals and beta-blockers were the most commonly used medications.

The burden of hyperkalemia in Germany - a real world evidence study assessing the treatment and costs of hyperkalemia

Background

Hyperkalemia (HK) can affect health outcomes and quality of life, as it is referred to as a potentially life-threatening condition caused by an increased serum potassium concentration in the blood. Patients suffering from heart failure or chronic kidney diseases are at a higher risk of HK, which can further be amplified by the treatment received. To date, data on HK prevalence is lacking for Germany and the aims of this study were to assess HK and compare health-relevant outcomes and healthcare costs between HK patients and non-HK patients.

Methods

The InGef research database containing healthcare claims of over 4 million individuals in Germany was utilized for this retrospective, matched cohort analysis. Patients with non-acute outpatient treated and a subgroup of patients with chronic HK, were identified in 2015 with an individual 1 year pre- and post-index period, taking the first observable HK diagnosis/treatment in 2015 into account as the index event. To identify non-acute outpatient treated HK patients, at least two ICD-10-GM diagnosis codes E87.5 “Hyperkalemia” and/or prescriptions of polystyrene sulfonate were required. Chronic HK patients had additional diagnoses and/or prescriptions in all quarters following the first observable HK diagnosis. Patients without HK were matched 1:1 to the respective HK cohorts.

Results

In the year 2015, 3333 patients with non-acute outpatient treated HK were identified of which 1693 were patients with chronic HK. After matching, 3191 and 1664 HK patients and controls were available for analysis. A significantly higher number of hospitalizations was observed for both HK cohorts in comparison to their matched controls. Dialysis initiation as well as the healthcare costs were higher for both HK cohorts when compared to their matched counterparts.

Conclusions

The disease burden was higher for patients with HK, based on a higher proportion of patients with dialysis initiation and higher healthcare costs.

Blood glucose reduction in patients treated with insulin and dextrose for hyperkalaemia

Background

Dextrose is commonly administered with insulin during the management of hyperkalaemia to avoid hypoglycaemia. Previous research has evaluated the incidence of hypoglycaemia; however, none have reported the extent of blood glucose reduction after this regimen. The aim of this study was to better characterise the changes in blood glucose and to identify patients who may have an increased response to insulin.

Methods

This was a multicentre retrospective study evaluating adult patients who received a regimen of 10 units of intravenous regular insulin plus 25 g of intravenous dextrose to manage hyperkalaemia between January 2014 and September 2016. The primary outcome was to evaluate the extent of blood glucose reduction (milligram per decilitre) up to 6 hours following the above regimen. Secondary outcomes included incidence of hypoglycaemia (blood glucose <70 mg/dL) and severe hypoglycaemia (blood glucose <40 mg/dL), and predictors of the extent of blood glucose reduction.

Results

A total of 90 patients were included. The median blood glucose change over 6 hours was −24 mg/dL (IQR −53 to 6 mg/dL). Hypoglycaemia developed in 20 patients (22.2%, 95% CI 14.1% to 32.2%) and five patients (5.6%, 95% CI 1.8% to 12.5%) had severe hypoglycaemia. Patients who developed hypoglycaemia had a median baseline blood glucose of 110 mg/dL (IQR 80 to 127 mg/dL), which decreased to a median value of 52 mg/dL (IQR 40 to 60 mg/dL). Higher baseline blood glucose was significantly associated with greater blood glucose reduction (coefficient −0.36, 95% CI −0.55 to −0.18, p<0.001).

Conclusions

The extent of blood glucose reduction is variable and hypoglycaemia is common. The high incidence of hypoglycaemia highlights the importance of frequent blood glucose monitoring.

A novel scoring system for assessing the severity of electrolyte and acid-base disorders and predicting outcomes in hospitalized patients

Electrolyte and acid-base disorders are commonly seen in critically ill and other hospitalized patients. A scoring system is needed to assess the severity of electrolyte and acid-base disorders and to predict outcome in hospital patients. Herein, we prospectively enrolled a total of 322,046 patients, including 84,700 patients in the derivation cohort and 237,346 in the validation cohort, in a large, tertiary hospital in East China from 2014 to 2017. A points-scoring system of general electrolyte and acid-base disorders with a sum of 20.8 points was generated by multiple logistic regression analysis of the derivation cohort. Receiver operating characteristic curve analysis showed that the optimal cut-off value of 2.0 was associated with 65.4% sensitivity and 88.4% specificity (area under the curve: 0.818 (95% CI 0.809 to 0.827)) to predict hospital mortality in the validation cohort. On Kaplan-Meier survival analysis, the five intervals of risk score (Q1: 0 to 2.0; Q2: 2.1 to 2.5; Q3: 2.6 to 3.3; Q4: 3.4 to 4.5; and Q5: >4.5 points) showed differences in hospital survival (p<0.001). Elevated (delta) risk score >2 during hospitalization increased the risk of hospital death, while those with a delta risk score <0 and <−2 points had higher survival rates. This novel scoring system could be used to evaluate and to dynamically monitor the severity of electrolyte and acid-base disorders in hospitalized patients.

Study design of Real World Evidence for Treatment of Hyperkalemia in the Emergency Department (REVEAL-ED): a multicenter, prospective, observational study

Objective

Hyperkalemia affects up to 10% of hospitalized patients and, if left untreated, can lead to serious cardiac arrhythmias or death. Although hyperkalemia is frequently encountered in the emergency department (ED), and is potentially life-threatening, standard of care for the treatment is poorly defined, with little supporting evidence. The main objectives of this observational study are to define the overall burden of hyperkalemia in the ED setting, describe its causes, the variability in treatment patterns and characterize the effectiveness and safety of ED standard of care therapies used in the United States.

Methods

This is an observational study evaluating the management of hyperkalemia in the ED. Two hundred and three patients who presented to the ED with a potassium value ≥5.5 mmol/L were enrolled in the study at 14 sites across the United States. Patients were treated per standard of care practices at the discretion of the patient’s physician. In patients who received a treatment for hyperkalemia, blood samples were drawn at pre-specified time points and serum potassium values were recorded. The change in potassium over 4 hours and the adverse events after standard of care treatment were analyzed.

Results and Conclusion

This article describes the background, rationale, study design, and methodology of the REVEAL-ED (Real World Evidence for Treatment of Hyperkalemia in the Emergency Department) trial, a multicenter, prospective, observational study evaluating contemporary management of patients admitted to the ED with hyperkalemia.

Sodium Zirconium Cyclosilicate (ZS-9): A Novel Agent for the Treatment of Hyperkalemia

Hyperkalemia is a potentially life-threatening electrolyte abnormality that may be caused by select medications, underlying organ dysfunction, or alterations in potassium homeostasis. Treatment for this condition has remained largely unchanged since the release of sodium polystyrene sulfonate (SPS) in 1958. Despite its widespread use, the safety and efficacy of SPS remains controversial. Two novel potassium-binding resins have emerged in recent years. Patiromer was the first of these to receive U.S. Food and Drug Administration approval for the treatment of hyperkalemia in October 2015. A second potassium-binding resin, a zirconium cyclosilicate currently known as ZS-9, may provide yet another alternative to the archetypal treatment with SPS. ZS-9 is an orally administered nonabsorbed inorganic compound that selectively binds potassium ions in vivo. Two phase III multicenter, randomized, placebo-controlled, double-blind trials have evaluated ZS-9 for the treatment of acute hyperkalemia. In this review, we discuss the pharmacology, clinical efficacy, safety, and potential place in therapy of ZS-9 for the enhanced elimination of potassium in the setting of hyperkalemia.

Vitamin D status predicts 30 day mortality in hospitalised cats

Vitamin D insufficiency, defined as low serum concentrations of the major circulating form of vitamin D, 25 hydroxyvitamin D (25(OH)D), has been associated with the development of numerous infectious, inflammatory, and neoplastic disorders in humans. In addition, vitamin D insufficiency has been found to be predictive of mortality for many disorders. However, interpretation of human studies is difficult since vitamin D status is influenced by many factors, including diet, season, latitude, and exposure to UV radiation. In contrast, domesticated cats do not produce vitamin D cutaneously, and most cats are fed a commercial diet containing a relatively standard amount of vitamin D. Consequently, domesticated cats are an attractive model system in which to examine the relationship between serum 25(OH)D and health outcomes. The hypothesis of this study was that vitamin D status would predict short term, all-cause mortality in domesticated cats. Serum concentrations of 25(OH)D, together with a wide range of other clinical, hematological, and biochemical parameters, were measured in 99 consecutively hospitalised cats. Cats which died within 30 days of initial assessment had significantly lower serum 25(OH)D concentrations than cats which survived. In a linear regression model including 12 clinical variables, serum 25(OH)D concentration in the lower tertile was significantly predictive of mortality. The odds ratio of mortality within 30 days was 8.27 (95% confidence interval 2.54-31.52) for cats with a serum 25(OH)D concentration in the lower tertile. In conclusion, this study demonstrates that low serum 25(OH)D concentration status is an independent predictor of short term mortality in cats.

Characterization of structure and function of ZS-9, a K+ selective ion trap

Hyperkalemia, a condition in which serum potassium ions (K+) exceed 5.0 mmol/L, is a common electrolyte disorder associated with substantial morbidity. Current methods of managing hyperkalemia, including organic polymer resins such as sodium polystyrene sulfonate (SPS), are poorly tolerated and/or not effective. Sodium zirconium cyclosilicate (ZS-9) is under clinical development as an orally administered, non-absorbed, novel, inorganic microporous zirconium silicate compound that selectively removes excess K+ in vivo. The development, structure and ion exchange properties of ZS-9 and its hypothesized mechanism of action are described. Based on calculation of the interatomic distances between the atoms forming the ZS-9 micropores, the size of the pore opening was determined to be ∼ 3 Å (∼ diameter of unhydrated K+). Unlike nonspecific organic polymer resins like SPS, the ZS-9 K+ exchange capacity (KEC) was unaffected by the presence of calcium (Ca2+) or magnesium ions (Mg2+) and showed>25-fold selectivity for K+ over either Ca2+ or Mg2+. Conversely, the selectivity of SPS for K+ was only 0.2-0.3 times its selectivity for Ca2+ or Mg2+in mixed ionic media. It is hypothesized that the high K+ specificity of ZS-9 is attributable to the chemical composition and diameter of the micropores, which possibly act in an analogous manner to the selectivity filter utilized by physiologic K+ channels. This hypothesized mechanism of action is supported by the multi-ion exchange studies. The effect of pH on the KEC of ZS-9 was tested in different media buffered to mimic different portions of the human gastrointestinal tract. Rapid K+ uptake was observed within 5 minutes - mainly in the simulated small intestinal and large intestinal fluids, an effect that was sustained for up to 1 hour. If approved, ZS-9 will represent a novel, first-in-class therapy for hyperkalemia with improved capacity, selectivity, and speed for entrapping K+ when compared to currently available options.

Major barriers responsible for malnutrition in hemodialysis patients: challenges to optimal nutrition

Background:

Nutritional barriers may contribute to malnutrition in hemodialysis (HD) patients. Higher rates of morbidity and mortality rates have been reported in malnourished HD patients. These patients are faced with different challenges affecting their nutritional status.

Objectives:

The aim of this cross-sectional study was to identify most important barriers responsible for malnutrition in HD patients.

Patients and Methods:

We randomly selected 255 of 800 stable HD patients from three HD centers with an age range of 18-85 years, who had been on hemodialysis for at least three months without any acute illness. Each patient was interviewed to evaluate malnutrition [subjective global assessment (SGA), malnutrition inflammation score (MIS)], and potential medical, behavioral and socioeconomic barriers. Body composition of patients was checked through bioelectrical impedance analysis (BIA). Routine clinical markers of malnutrition such as serum albumin and total protein were measured using standard automated techniques. Binary logistic regression model was used to find the association between nutritional markers and potential barriers.

Results:

Patients with higher SGA had lower knowledge about general nutrition [odds ratio (OR), 1.3], potassium (OR, 1.89), difficulty chewing (OR, 1.16), and shopping (OR, 1.16). Those with greater MIS scores had poor appetite (OR, 1.3), depression (OR, 1.21), and difficulty with cooking (OR, 1.15). Lower BCM (body cell mass) was associated with poor appetite (OR, 0.92) and needed help for cooking (OR, 0.88). Patients with higher BFMI (body fat mass index) had insufficient general nutrition (OR, 1.15), and protein (OR, 1.27) knowledge, and needed help for shopping (OR, 1.14). Moreover, patients with higher SGA scores were those with older age and longer duration of HD.

Conclusions:

Three medical barriers (poor appetite, depression and difficulty chewing), one behavioral barrier (poor total nutrition, protein, and potassium knowledge), and one socioeconomic barrier (needing help for shopping and cooking) were independently associated with nutritional markers.

Do hemolyzed potassium specimens need to be repeated?

BACKGROUND

In the emergency department (ED), hyperkalemia in the presence of hemolysis is common. Elevated hemolyzed potassium levels are often repeated by emergency physicians to confirm pseudohyperkalemia and to exclude a life-threatening true hyperkalemia.

OBJECTIVES

We hypothesize that in patients with a normal renal function, elevated hemolyzed potassium, and normal electrocardiogram (ECG), there may not be a need for further treatment or repeat testing and increased length of stay.

METHODS

Data were prospectively enrolled patients presenting to the ED from July 2011 to February 2012. All adult subjects who had a hemolyzed potassium level ≥ 5.5 mEq/dL underwent a repeat potassium level and ECG. The incidence of true hyperkalemia in this population was measured.

RESULTS

A total of 45 patients were enrolled. The overall median age was 52 years (range 25-83 years); 22 were female (49%). In patients with hyperkalemia on initial blood draw and glomerular filtration rate (GFR) ≥ 60 (n = 45), the negative predictive value was 97.8% (95% confidence interval [CI] 88.2-99.9%). When patients had hyperkalemia on initial blood draw, GFR ≥ 60, and a normal ECG (n = 42), the negative predictive value was 100% (95% CI 93.1-100%).

CONCLUSIONS

In the setting of hemolysis, GFR ≥ 60 mL/min in conjunction with a normal ECG is a reliable predictor of pseudohyperkalemia and may eliminate the need for repeat testing. In patients with a normal GFR who are otherwise deemed safe for discharge, our results indicate there is no need for repeat testing.

Increasing plasma [K+] by intravenous potassium infusion reduces NCC phosphorylation and drives kaliuresis and natriuresis

Dietary potassium loading results in rapid kaliuresis, natriuresis, and diuresis associated with reduced phosphorylation (p) of the distal tubule Na(+)-Cl(-) cotransporter (NCC). Decreased NCC-p inhibits NCC-mediated Na(+) reabsorption and shifts Na(+) downstream for reabsorption by epithelial Na(+) channels (ENaC), which can drive K(+) secretion. Whether the signal is initiated by ingesting potassium or a rise in plasma K(+) concentration ([K(+)]) is not understood. We tested the hypothesis, in male rats, that an increase in plasma [K(+)] is sufficient to reduce NCC-p and drive kaliuresis. After an overnight fast, a single 3-h 2% potassium (2%K) containing meal increased plasma [K(+)] from 4.0 ± 0.1 to 5.2 ± 0.2 mM; increased urinary K(+), Na(+), and volume excretion; decreased NCC-p by 60%; and marginally reduced cortical Na(+)-K(+)-2Cl(-) cotransporter (NKCC) phosphorylation 25% (P = 0.055). When plasma [K(+)] was increased by tail vein infusion of KCl to 5.5 ± 0.1 mM over 3 h, significant kaliuresis and natriuresis ensued, NCC-p decreased by 60%, and STE20/SPS1-related proline alanine-rich kinase (SPAK) phosphorylation was marginally reduced 35% (P = 0.052). The following were unchanged at 3 h by either the potassium-rich meal or KCl infusion: Na(+)/H(+) exchanger 3 (NHE3), NHE3-p, NKCC, ENaC subunits, and renal outer medullary K(+) channel. In summary, raising plasma [K(+)] by intravenous infusion to a level equivalent to that observed after a single potassium-rich meal triggers renal kaliuretic and natriuretic responses, independent of K(+) ingestion, likely driven by decreased NCC-p and activity sufficient to shift sodium reabsorption downstream to where Na(+) reabsorption and flow drive K(+) secretion.

Bolus administration of intravenous glucose in the treatment of hyperkalemia: a randomized controlled trial

BACKGROUND

Hyperkalemia is a common medical emergency that may result in serious cardiac arrhythmias. Standard therapy with insulin plus glucose reliably lowers the serum potassium concentration ([K(+)]) but carries the risk of hypoglycemia. This study examined whether an intravenous glucose-only bolus lowers serum [K(+)] in stable, nondiabetic, hyperkalemic patients and compared this intervention with insulin-plus-glucose therapy.

METHODS

A randomized, crossover study was conducted in 10 chronic hemodialysis patients who were prone to hyperkalemia. Administration of 10 units of insulin with 100 ml of 50% glucose (50 g) was compared with the administration of 100 ml of 50% glucose only. Serum [K(+)] was measured up to 60 min. Patients were monitored for hypoglycemia and EKG changes.

RESULTS

Baseline serum [K(+)] was 6.01 ± 0.87 and 6.23 ± 1.20 mmol/l in the insulin and glucose-only groups, respectively (p = 0.45). At 60 min, the glucose-only group had a fall in [K(+)] of 0.50 ± 0.31 mmol/l (p < 0.001). In the insulin group, there was a fall of 0.83 ± 0.53 mmol/l at 60 min (p < 0.001) and a lower serum [K(+)] at that time compared to the glucose-only group (5.18 ± 0.76 vs. 5.73 ± 1.12 mmol/l, respectively; p = 0.01). In the glucose-only group, the glucose area under the curve (AUC) was greater and the insulin AUC was smaller. Two patients in the insulin group developed hypoglycemia.

CONCLUSION

Infusion of a glucose-only bolus caused a clinically significant decrease in serum [K(+)] without any episodes of hypoglycemia.

Severe hyperkalaemia: demographics and outcome

Background

Few studies have evaluated the prevalence of severe hyperkalaemia in unselected patient populations. We identified all episodes of severe hyperkalaemia occurring in 1 year, and described patient demographics, clinical response and outcome. We also assessed junior doctor knowledge of its causes and significance.

Materials and methods

A retrospective interrogation of the database of the regional biochemical laboratory identified all episodes of severe hyperkalaemia (K≥ 6.5 mmol/L) occurring in 2011. The understanding of trainee doctors of the importance, causes and treatment of severe hyperkalaemia was assessed by structured questionnaire.

Results

Severe hyperkalaemia was recorded in 433 samples (365 patients) giving a prevalence of 0.11%. Thirty-six per cent of episodes occurred in patients under the care of a nephrologist, who were significantly younger than those not under the care of a nephrologist. In the nephrology cohort, 86% occurred in patients with chronic kidney disease (CKD), the majority of which had CKD Stage 5. In the non-nephrology cohort, only 65% occurred in the context of CKD, which was equally distributed between Stages 3 and 5 CKD. In both patient groups, roughly 50% of episodes occurred in association with acute kidney injury (AKI). Acute mortality (death within 48 h of documented severe hyperkalaemia) was higher in the non-nephrology compared with the nephrology cohort. Time to repeat serum potassium was influenced by the clinical setting with shorter time to repeat for acute care compared with ward settings. Assessment of trainee doctor's knowledge suggested significant deficiencies in relation to severe hyperkalaemia.

Conclusions

The prevalence of severe hyperkalaemia was low and occurred predominantly in the context of CKD and/or AKI. The majority of episodes occurred in patients not under the care of a nephrologist. Variability in time to repeat serum potassium levels suggested deficiencies in care, and assessment of trainee doctor’s knowledge suggests the need for further educational initiatives to highlight its importance.

Risk of hyperkalemia in patients with moderate chronic kidney disease initiating angiotensin converting enzyme inhibitors or angiotensin receptor blockers: a randomized study

Background

Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are renoprotective but both may increase serum potassium concentrations in patients with chronic kidney disease (CKD). The proportion of affected patients, the optimum follow-up period and whether there are differences between drugs in the development of this complication remain to be ascertained.

Methods

In a randomized, double-blind, phase IV, controlled, crossover study we recruited 30 patients with stage 3 CKD under restrictive eligibility criteria and strict dietary control. With the exception of withdrawals, each patient was treated with olmesartan and enalapril separately for 3 months each, with a 1-week wash-out period between treatments. Patients were clinically assessed on 10 occasions via measurements of serum and urine samples. We used the Cochran–Mantel–Haenszel statistics for comparison of categorical data between groups. Comparisons were also made using independent two-sample t-tests and Welch’s t-test. Analysis of variance (ANOVA) was performed when necessary. We used either a Mann–Whitney or Kruskal-Wallis test if the distribution was not normal or the variance not homogeneous.

Results

Enalapril and olmesartan increased serum potassium levels similarly (0.3 mmol/L and 0.24 mmol/L respectively). The percentage of patients presenting hyperkalemia higher than 5 mmol/L did not differ between treatments: 37% for olmesartan and 40% for enalapril. The mean e-GFR ranged 46.3 to 48.59 ml/mint/1.73 m² in those treated with olmesartan and 46.8 to 48.3 ml/mint/1.73 m² in those with enalapril and remained unchanged at the end of the study. The decreases in microalbuminuria were also similar (23% in olmesartan and 29% in enalapril patients) in the 4 weeks time point. The percentage of patients presenting hyperkalemia, even after a two month period, did not differ between treatments. There were no appreciable changes in sodium and potassium urinary excretion.

Conclusions

Disturbances in potassium balance upon treatment with either olmesartan or enalapril are frequent and without differences between groups. The follow-up of these patients should include control of potassium levels, at least after the first week and the first and second month after initiating treatment.

Trial registration

The trial EudraCT “2008-002191-98”.

Renal tubular acidosis type IV in hyperkalaemic patients--a fairy tale or reality?

OBJECTIVE

Hyperkalaemia is a common feature in hospitalized patients and often attributed to drugs antagonizing the renin-angiotensin-aldosterone system (RAAS) and/or acute kidney injury (AKI), despite significantly preserved glomerular filtration rate (GFR). The objective of this study was to determine the prevalence and role of renal tubular acidosis type IV (RTA IV) in the development of significant hyperkalaemia.

DESIGN

A single-centre retrospective study.

PATIENTS

Patients admitted to a University Hospital over 12 months.

MEASUREMENTS

Patients with a potassium value > 6·0 mm were identified. Clinical and laboratory data were revisited, and patients with a normal anion gap metabolic acidosis were evaluated for the existence of RTA IV.

RESULTS

A total of 57 patients having significant hyperkalaemia (>6·0 mm) were identified. Twelve patients had end-stage renal disease, while 21 patients had solely AKI or progressive chronic renal failure. RTA IV was present in 24 patients (42%), of whom 71% had pre-existing renal insufficiency because of diabetic nephropathy or tubulointerstitial nephritis. All hyperkalaemic patients with urinary/serum electrolytes suggestive of RTA IV had evidence of AKI, but creatinine levels were significantly lower (P < 0·05), while the number of drugs antagonizing the RAAS was comparable.

CONCLUSION

We demonstrated that RTA IV (i) is very common in patients with hyperkalaemia; (ii) should always be suspected in hyperkalaemic patients with only moderately impaired GFR; and (iii) may result in significant hyperkalaemia in the presence of both AKI and drugs antagonizing the RAAS.

Severe hyperkalemia requiring hospitalization: predictors of mortality

Introduction

Severe hyperkalemia, with potassium (K⁺) levels ≥ 6.5 mEq/L, is a potentially life-threatening electrolyte imbalance. For prompt and effective treatment, it is important to know its risk factors, clinical manifestations, and predictors of mortality.

Methods

An observational cohort study was performed at 2 medical centers. A total of 923 consecutive Korean patients were analyzed. All were 19 years of age or older and were hospitalized with severe hyperkalemia between August 2007 and July 2010; the diagnosis of severe hyperkalemia was made either at the time of admission to the hospital or during the period of hospitalization. Demographic and baseline clinical characteristics at the time of hyperkalemia diagnosis were assessed, and clinical outcomes such as in-hospital mortality were reviewed, using the institutions' electronic medical record systems.

Results

Chronic kidney disease (CKD) was the most common underlying medical condition, and the most common precipitating factor of hyperkalemia was metabolic acidosis. Emergent admission was indicated in 68.6% of patients, 36.7% had electrocardiogram findings typical of hyperkalemia, 24.5% had multi-organ failure (MOF) at the time of hyperkalemia diagnosis, and 20.3% were diagnosed with severe hyperkalemia at the time of cardiac arrest. The in-hospital mortality rate was 30.7%; the rate was strongly correlated with the difference between serum K⁺ levels at admission and at their highest point, and with severe medical conditions such as malignancy, infection, and bleeding. Furthermore, a higher in-hospital mortality rate was significantly associated with the presence of cardiac arrest and/or MOF at the time of diagnosis, emergent admission, and intensive care unit treatment during hospitalization. More importantly, acute kidney injury (AKI) in patients with normal baseline renal function was a strong predictor of mortality, compared with AKI superimposed on CKD.

Conclusions

Severe hyperkalemia occurs in various medical conditions; the precipitating factors are similarly diverse. The mortality rate is especially high in patients with severe underlying disease, coexisting medical conditions, and those with normal baseline renal function.

Drug-induced life-threatening potassium disturbances detected by a pharmacovigilance program from laboratory signals

PURPOSE

Detection and reporting of drug-induced life-threatening potassium disturbances and the study of associated factors under a Pharmacovigilance Program using Laboratory Signals at a Hospital (PPLSH) during a 2-year period.

METHODS

All serum potassium levels <2 mmol/l or >7 mmol/l detected at admission to the hospital, including those of patients who died in the emergency ward or during hospitalization, were monitored prospectively from January 2009 through to December 2010. The incidence rate of each etiology of potassium disturbances was calculated. Factors associated with drug-induced potassium disturbances were detected using a multiple logistic regression model.

RESULTS

The incidence of true life-threatening drug-induced hyper- and hypokalemia events was 3 and 4.32 (Poisson 95 % confidence interval 1.62-10.24), respectively, per 10,000 admissions. Of the severe potassium disturbances, 32.3 % were drug-induced, and 23 % were lethal. We identified previously undescribed pharmacological causes of hyperkalemia (risedronate, doxazosin) and hypokalemia (acyclovir, teicoplanin, cefepime, meropenem, dexketoprofen colistimethate). Significant predictor factors associated with drug-induced hyperkalemia were the use of polypharmacy (>5 drugs), age (>74 years), sex (female) and kidney disease (glomerular filtration rate <60 ml/min) with the presence of ≥4 comorbid conditions. The only predictor of drug-induced hypokalemia was the use of >5 drugs. The triggering factor associated with drug-induced hyperkalemia and hypokalemia was azotemia and hypoalbuminemia, respectively.

CONCLUSIONS

Drug-induced life-threatening potassium disturbances remain a relevant problem. Potential strategies for prevention are to avoid polypharmacy, early discontinuation of treatment of drugs causing hyperkalemia or nephrotoxicity in cases of various clinical situations (cardiac descompensation, infection, hypovolemia) or obstructive causes, and insistence on albumin control during hospitalization.

Incidence of hypoglycemia following insulin-based acute stabilization of hyperkalemia treatment

PURPOSE

The aim of this study was to assess the incidence of hypoglycemia in hospitalized patients following acute treatment of hyperkalemia with insulin. A characterization of the affected patients and the administered insulin/dextrose regimens was also performed.

METHODS

A retrospective search of the electronic records of a large university-based tertiary care hospital was conducted, from June 1, 2009 to December 1, 2009, to identify patients who developed hypoglycemia following acute stabilization of hyperkalemia treatment with regular insulin.

RESULTS

Of 219 hyperkalemic patients who met the criteria of the study, 19 patients (8.7%) were identified ashypoglycemic (blood glucose <70 mg/dl), and 5 of these patients (2.3% of study patients) were classified as severely hypoglycemic (blood glucose <40 mg/dl). Fifteen (79%) of the hypoglycemic patients had acute kidney injury or were end-stage renal disease patients on hemodialysis at the time of treatment. Fifty-eight percent of the hypoglycemic events occurred following the commonly employed 10 units of regular insulin and 25 gm of dextrose 50% treatment regimen.

CONCLUSION

Iatrogenic hypoglycemia, as a result of treatment for hyperkalemia, is a common occurrence. Hyperkalemia occurs disproportionately in patients with acute kidney injury or end-stage renal disease, and these patients are predisposed to an increased risk of hypoglycemia. The risk of severe hypoglycemia escalates inpatients with lower body weight and creatinine clearance.Hypoglycemia risk can be minimized by providing sufficient dextrose in the treatment regimen, however, patient variability in treatment response dictates careful blood glucose monitoring before and after treatment.

Four nephrology myths debunked

There are many controversial topics relating to renal disease in hospitalized patients. The aim of this review is to shed light on some important and often debated issues. Hypothyroidism, unlike myxedema, is not a cause of hyponatremia (although it can be sometimes seen in conjunction with the latter) and additional investigations should be done to determine its etiology. Sodium bicarbonate is effective for treatment of hyperkalemia primarily by enhancing renal potassium elimination rather than by translocating potassium into cells. Acetaminophen can be a cause of metabolic acidosis by causing 5-oxoprolinuria. Furosemide (and sulfa containing diuretics) can safely be used in patients with an allergy to sulfa-containing antibiotics (SCA).

Frequency of laboratory measurement and hyperkalaemia in hospitalised patients using serum potassium concentration increasing drugs

PURPOSE

Although, drug-drug interactions (DDIs) between potassium-increasing drugs (PIDs) are known risk factors for developing hyperkalaemia, not much is known about their risk and management strategies during hospitalisation. This study examines the frequency of serum potassium measurements and hyperkalaemia in hospitalised patients, based on the use of one or more PIDs, and the determinants thereof.

METHODS

Adult patients hospitalised in the University Medical Centre Utrecht between 2006 and 2008 were included in this cross-sectional study. The frequency of serum potassium measurements and of hyperkalaemia were compared between patients using only one PID at a time (monotherapy group) and patients using two or more PIDs concomitantly (interaction group). The determinants studied were renal failure, diabetes mellitus, use of diuretics, type of DDI, start of the PIDs within the hospital versus continued home medication and medical speciality.

RESULTS

Serum potassium was measured more frequently in the interaction group than in the monotherapy group [67 vs. 56%; relative risk (RR) 1.19, 95% confidence interval (CI) 1.14-1.24] and the risk of hyperkalaemia was also increased in the interaction group (9.9 vs. 5.9%, RR 1.7, 95% CI 1.3-2.1). The combination of potassium-sparing diuretics plus a potassium supplement, start of the PID within the hospital and hospitalisation in non-internal medicine departments was associated with higher relative risk estimates for hyperkalaemia.

CONCLUSIONS

Among our patient cohort, even when physicians received a direct pop-up to monitor serum potassium levels when prescribing two PIDs concomitantly, serum potassium levels were not measured in 33% of patients, and 10% of patients developed hyperkalaemia. Improved management strategies and/or clinical decision-support systems are needed to decrease the frequency of hyperkalaemia following DDIs.

Left bundle branch block (LBBB) masks changes due to hyperkalemia: a myth

Left bundle branch block masks ischemic changes but not those due to electrolyte imbalance. Peaking of T waves, prolongation of PR interval, diminution/absence of P wave, and widening of QRS complex can still be appreciated if one carefully compares the baseline ECG to the presenting ECG.

Serum potassium and outcomes in CKD: insights from the RRI-CKD cohort study

BACKGROUND AND OBJECTIVES

The relationship between serum potassium (S(K)) and mortality in chronic kidney disease (CKD) has not been systematically investigated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the predictors and mortality association of S(K) in the Renal Research Institute CKD Study cohort, wherein 820 patients with CKD were prospectively followed at four US centers for an average of 2.6 years. Predictors of S(K) were investigated using linear and repeated measures regression models. Associations between S(K) and mortality, the outcomes of ESRD, and cardiovascular events in time-dependent Cox models were examined.

RESULTS

The mean age was 60.5 years, 80% were white, 90% had hypertension, 36% had diabetes, the average estimated GFR was 25.4 ml/min per 1.73 m(2), and mean baseline S(K) was 4.6 mmol/L. Higher S(K) was associated with male gender, lower estimated GFR and serum bicarbonate, absence of diuretic and calcium channel blocker use, diabetes, and use of angiotensin-converting enzyme inhibitors and/or statins. A U-shaped relationship between S(K) and mortality was observed, with mortality risk significantly greater at S(K) < or = 4.0 mmol/L compared with 4.0 to 5.5 mmol/L. Risk for ESRD was elevated at S(K) < or = 4 mmol/L in S(K) categorical models. Only the composite of cardiovascular events or death as an outcome was associated with higher S(K) (> or = 5.5).

CONCLUSIONS

Although clinical practice usually emphasizes greater attention to elevated S(K) in the setting of CKD, our results suggest that patients who have CKD and low or even low-normal S(K) are at higher risk for dying than those with mild to moderate hyperkalemia.

Monitoring of drug-associated electrolyte disturbances in a hospital

PURPOSE

The aim of our study was to find drug-associated changes in serum levels of major electrolytes using clinical-event monitoring method.

METHODS

During 1-year period, electrolyte disturbances in serum samples from patients of Clinical Center Kragujevac, Serbia, were monitored in central biochemical facility. A sample of 982 patients was randomly selected from total population of 43,120 patients whose electrolyte serum levels were measured in the facility during the study period.

RESULTS

Clinically important drug-associated electrolyte disturbances were detected in 181 patient. There were 25 significant associations between the drugs and electrolyte values outside the reference range. However, only four causal connections were established: use of normal saline infusion with hypernatremia (OR 6.97, 95%CI 2.24-21.67), theophylline with acid-base disturbances (7.75, 1.46-41.02), polygeline infusion with decrease in bicarbonate levels (4.08, 1.42-11.73), and association of risperidone and hypocalcemia (4.10, 1.42-11.81).

CONCLUSION

Although clinical-event monitoring method is far from optimal, it could quantify the known risks and provide evidence for credible hypothesis of drug adverse reactions, based on both relevant biological pathways and reasonable clinical thinking, as it was the case in our study.

Incidence of risk factors for developing hyperkalemia when using ACE inhibitors in cardiovascular diseases

STUDY OBJECTIVE

To determine the incidence of and the risk factors associated with hyperkalemia, induced by ACEI-drug interactions among cardiac patients.

SETTING

Five medical and cardiology wards of a tertiary care center in Malaysia.

SUBJECTS

Five hundred cardiac inpatients, who received ACEIs concomitantly with other interacting drugs.

METHOD

This was a prospective cohort study of 500 patients with cardiovascular diseases admitted to Penang Hospital between January to August 2006, who received ACEIs concomitantly with other interacting drugs. ACEI-drug interactions of clinical significance were identified using available drug information resources. Drug Interaction Probability Scale (DIPS) was used to assess the causality of association between ACEI-drug interactions and the adverse outcome (hyperkalemia).

MAIN OUTCOME MEASURE

Hyperkalemia as an adverse clinical outcome of the interaction was identified from laboratory investigations.

RESULTS

Of the 489 patients included in the analysis, 48 (9.8%) had hyperkalemia thought to be associated with ACEI-drug interactions. Univariate analysis using binary logistic regression revealed that advanced age (60 years or more), and taking more than 15 medications were independent risk factors significantly associated with hyperkalemia. However, current and previous smoking history appeared to be a protective factor. Risk factors identified as predictors of hyperkalemia secondary to ACEI-drug interactions by multi-logistic regression were: advanced age (adjusted OR 2.3, CI 1.07-5.01); renal disease (adjusted OR 4.7, CI 2.37-9.39); hepatic disease (adjusted OR 5.2, CI 1.08-25.03); taking 15-20 medications (adjusted OR 4.4, CI 2.08-9.19); and taking 21-26 medications (adjusted OR 9.0, CI 1.64-49.74).

CONCLUSION

Cardiac patients receiving ACEIs concomitantly with potentially interacting drugs are at high risk of experiencing hyperkalemia. Old age, renal disease, hepatic disease, and receiving large number of medications are factors that may significantly increase their vulnerability towards this adverse outcome; thus, frequent monitoring is advocated.

Risk factors associated with a high velocity of the development of hyperkalaemia in hospitalised patients

BACKGROUND/OBJECTIVE

Drugs have been recognised as a primary or contributing cause of hyperkalaemia, especially when administered to patients with underlying risk factors. The objective of this study was to analyse the influence of the known risk factors for hyperkalaemia on the velocity of the development of hyperkalaemia.

STUDY DESIGN/METHODS

Clinical characteristics, laboratory data and medication profiles of patients developing hyperkalaemia (serum potassium>or=5.0 mmol/L) hospitalised between 2000 and 2004 in the University Hospital Basel, Switzerland, were recorded. Factors associated with a high velocity of the development of hyperkalaemia were detected using a multiple logistic regression model. Subsequently, the velocity during a defined observation period was compared between patients with one risk factor and patients with two or more risk factors. Finally, the dose effects of drugs identified as risk factors for a high velocity of the development of hyperkalaemia were analysed using two sample comparisons.

RESULTS

A random sample of 551 hospitalised patients was analysed. Compared with the drug treatment at entry, significantly more patients during the hospitalisation were treated with drugs associated with hyperkalaemia, such as heparins (p<0.001), ACE inhibitors or angiotensin receptor blockers (ARBs) [p=0.002], potassium supplements (p<0.001), potassium-sparing diuretics (p<0.001) and/or NSAIDs or selective cyclo-oxygenase (COX)-2 inhibitors (p<0.001). Risk factors associated with a high velocity of the development of hyperkalaemia were use of potassium supplements (adjusted odds ratio [OR] 3.386; 95% CI 2.251, 5.091), severe renal impairment (OR 3.119; 95% CI 2.007, 4.850), use of ACE inhibitors or ARBs (OR 2.642; 95% CI 1.742, 4.006), use of potassium-sparing diuretics (OR 2.065; 95% CI 1.310, 3.254), and diabetes mellitus (OR 1.525; 95% CI 1.005, 2.313). The velocity of the development of hyperkalaemia significantly increased in patients with two or more risk factors. Dose effects could be found for potassium supplements (p=0.006) and potassium-sparing diuretics (p=0.007), but not for ACE inhibitors or ARBs (p=0.289). In contrast, the use of kaliuretics (loop diuretics or thiazides) was associated with a decreased velocity of the development of hyperkalaemia in patients with serious renal impairment (p=0.016) and in patients treated with two or more drug classes associated with a high velocity of the development of hyperkalaemia (p=0.001).

CONCLUSIONS

Risk factors associated with a high velocity of the development of hyperkalaemia are use of potassium supplements>severe renal impairment>use of ACE inhibitors or ARBs>use of potassium-sparing diuretics>diabetes mellitus. The presence of two or more of these risk factors is associated with an even faster development of hyperkalaemia. Clinicians should be aware of these risk factors in order to avoid a rapid development of potentially life-threatening hyperkalaemia.

Resuscitative hyperkalemia in noncrush trauma: a prospective, observational study

The trauma patient is exposed to physiologic processes and life-saving interventions that predispose to hyperkalemia. Severe elevations in potassium levels subject this compromised patient to additional cardiac risks in the periresuscitative period. Recent advances in the care of the massively traumatized patient may or may not increase the risk for hyperkalemia. This prospective, observational study was undertaken to define the period prevalence of hyperkalemia (plasma potassium level > or = 5.5 mmol/L) in a noncrush trauma population during the initial resuscitative period and to identify potential risk factors for the development of hyperkalemia. A total of 131 patients were studied during the initial 12 h after admission for noncrush trauma. The period prevalence of hyperkalemia was 29.0%. Hyperkalemic patients had dramatic shifts in plasma potassium levels compared with nonhyperkalemic patients. Five patients, all from the hyperkalemic group, died. By multivariate logistic regression analysis, independent risk factors for hyperkalemia were an emergency department plasma potassium level of 4.0 mmol/L or higher (relative risk 3.40; 95% confidence interval 1.17 to 9.84; P = 0.024 versus baseline potassium level < 4.0 mmol/L) and transfusion of cell- or plasma-based products (relative risk 10.56; 95% confidence interval 3.62 to 30.78; P < 0.001 per log-transformed unit). The prevalence of hyperkalemia during trauma resuscitation was not reported previously. Given the arrhythmic risks of hyperkalemia, particular caution is necessary with trauma patients who present with plasma potassium levels > 4.0 mmol/L and require aggressive transfusion support.

Clinical laboratory findings associated with in-hospital mortality

The diagnostic approach and the clinical management of critically ill patients is challenging. The recognition of biomarkers related to in-hospital mortality is of importance for identification of patients at increased risk of death. Many prediction models assessing the severity of illness and likelihood of hospital survival were developed using logistic regression analyses. These models include several laboratory parameters, such as white blood cell counts, serum bilirubin, serum albumin, blood glucose, serum electrolytes and markers which reflect acid-base disturbances. Recently, several other biomarkers, including troponin, B-type natriuretic peptide (BNP), N-terminal proBNP, C-reactive protein, procalcitonin, cholesterol and coagulation related markers have emerged as clinically useful tools for risk stratification and mortality prediction of heterogeneous and more specific subgroups of critically ill patients. More investigations are required to verify whether risk stratification based on mortality-related biomarkers may translate into targeted treatment strategies to improve clinical outcome of the critical illness. Biomarkers which are related to in-hospital mortality are highlighted in the current review.

Specificity of noninvasive blood glucose sensing using optical coherence tomography technique: a pilot study

Noninvasive monitoring of blood glucose concentration in diabetic patients would significantly reduce complications and mortality associated with this disease. In this paper, we experimentally and theoretically studied specificity of noninvasive blood glucose monitoring with the optical coherence tomography (OCT) technique. OCT images and signals were obtained from skin of Yucatan micropigs and New Zealand rabbits. Obtained results demonstrate that: (1) several body osmolytes may change the refractive index mismatch between the interstitial fluid (ISF) and scattering centres in tissue, however the effect of the glucose is approximately one to two orders of magnitude higher; (2) an increase of the ISF glucose concentration in the physiological range (3-30 mM) may decrease the scattering coefficient by 0.22% mM(-1) due to cell volume change; (3) stability of the OCT signal slope is dependent on tissue heterogeneity and motion artefacts; and (4) moderate skin temperature fluctuations (+/- 1 degree C) do not decrease accuracy and specificity of the OCT-based glucose sensor, however substantial skin heating or cooling (several degrees C) significantly change the OCT signal slope. These results suggest that the OCT technique may provide blood glucose concentration monitoring with sufficient specificity under normal physiological conditions.