Hypokalaemia: Improving the investigation, management and therapeutic monitoring of hypokalaemic medical inpatients at a district general hospital

Optimising patient care: comprehensive evaluation of inpatient hypokalaemia

Hypokalaemia is a common electrolyte disorder affecting hospitalised patients. It is associated with adverse outcomes including increased mortality. Inpatients with hypokalaemia need a different approach to workup and management as the aetiologies and progression of the hypokalaemia are distinct to outpatients. Potassium homeostasis is predominantly maintained by renal potassium handling. The clinical manifestations of hypokalaemia depend on the severity of hypokalaemia, however, most of the findings are non-specific. The approach to management is guided by the severity of the hypokalaemia and the underlying aetiology. Oral potassium replacement can be used in many cases of mild hypokalaemia. Intravenous replacement of potassium is necessary for many inpatients. Close monitoring is essential to ensure adequacy and to prevent adverse outcomes. An interdisciplinary approach with critical care input is needed in severe cases, and in patients where routine intravenous replacement may not be feasible (e.g., patients with heart failure). In addition to replacement, the cornerstone of management is a comprehensive review of the patient to identify the underlying cause of the hypokalaemia and the factors sustaining it. In patients in whom the cause is not apparent, or the potassium does not improve as anticipated, a referral to nephrology or endocrinology should be considered. This paper reviews the assessment of hypokalaemia in a hospital setting. It is aimed at early career doctors on the wards to help carry out a thorough evaluation. It also provides a useful framework for management.

Nanoporous Carbon Materials as Solid Contacts for Microneedle Ion-Selective Sensors

Continuous sensing of biomarkers, such as potassium ions or pH, in wearable patches requires miniaturization of ion-selective sensor electrodes. Such miniaturization can be achieved by using nanostructured carbon materials as solid contacts in microneedle-based ion-selective and reference electrodes. Here we compare three carbon materials as solid contacts: colloid-imprinted mesoporous (CIM) carbon microparticles with ∼24-28 nm mesopores, mesoporous carbon nanospheres with 3-9 nm mesopores, and Super P carbon black nanoparticles without internal porosity but with textural mesoporosity in particle aggregates. We compare the effects of carbon architecture and composition on specific capacitance of the material, on the ability to incorporate ion-selective membrane components in the pores, and on sensor performance. Functioning K+ and H+ ion-selective electrodes and reference electrodes were obtained with gold-coated stainless-steel microneedles using all three types of carbon. The sensors gave near-Nernstian responses in clinically relevant concentration ranges, were free of potentially detrimental water layers, and showed no response to O2. They all exhibited sufficiently low long-term potential drift values to permit calibration-free, continuous operation for close to 1 day. In spite of the different specific capacitances and pore architecture of the three types of carbon, no significant difference in potential stability for K+ ion sensing was observed between electrodes that used each material. In the observed drift values, factors other than the carbon solid contact are likely to play a role, too. However, for pH sensing, electrodes with CIM as a carbon solid contact, which had the highest specific capacitance and best access to the pores, exhibited better long-term stability than electrodes with the other carbon materials.

Associations between serum potassium and adverse clinical outcomes: A systematic literature review

BACKGROUND AND OBJECTIVES

Despite the growing body of evidence characterising the association between serum potassium levels and adverse clinical outcomes, a contemporary summary of available evidence is currently lacking. The objective of this study, therefore, was to undertake a systematic literature review to identify all relevant evidence assessing risk factors associated with the incidence of hyperkalaemia (HK) and also quantifying the effect of serum potassium levels on risk of adverse clinical outcomes.

METHODS

PubMed (Medline and Medline In-Process), Embase and the Cochrane Library were searched for studies published between January 2002 and November 2018. Search inclusion criteria included studies describing either the incidence of HK events and any associated risk factors, or associations between HK or serum potassium concentration and adverse clinical outcomes including mortality, hospitalisation, major adverse cardiac events (MACE) and renin-angiotensin-aldosterone system inhibitors (RAASi) discontinuation in adult patients with chronic kidney disease (CKD), heart failure (HF), type 2 diabetes (T2DM) or hypertension.

RESULTS

The search identified 1,897 publications. From these, a total of 123 studies met the inclusion criteria and were included in the review. The most commonly identified risk factors associated with HK events were the presence of CKD or renal impairment, T2DM, HF, hypertension, RAASi use and mineralocorticoid receptor antagonist use. Potassium levels both above and below the normal range were consistently associated with adverse clinical outcomes, with relative and absolute risks of outcomes increasing with severity of hyper- or hypokalaemia. These associations were consistently reported across a broad range of patient population types and study types.

CONCLUSION

The current body of published evidence is compelling in its confirmation of the associations between serum potassium levels and adverse clinical outcomes. This review further highlights the importance of avoiding both hyper- and hypokalaemia, in order to reduce risk of mortality, hospitalisation, MACE and RAASi discontinuation or down-titration.

Clinical rule-guided pharmacists' intervention in hospitalized patients with hypokalaemia: A time series analysis

WHAT IS KNOWN AND OBJECTIVE

Physicians' response to moderate and severe hypokalaemia in hospitalized patients is frequently suboptimal, leading to increased risk of cardiac arrhythmias and sudden death. While actively alerting physicians on all critical care values using telephone or electronic pop-ups can improve response, it can also lead to alert fatigue and frustration due to non-specific and overdue alerts. Therefore, a new method was tested. A clinical rule built into a clinical decision support system (CDSS) generated alerts for patients with a serum potassium level (SPL) <2.9 mmol/L without a prescription for potassium supplementation. If the alert was deemed clinically relevant, a pharmacist contacted the physician. The aim of this study was to evaluate the impact of the clinical rule-guided pharmacists' intervention compared to showing passive alerts in the electronic health records on outcome in patients who developed hypokalaemia (<2.9 mmol/L) during hospitalization.

METHODS

A before (2007-2009) and after (2010-2017) study with time series design was performed. Pre-intervention, physicians were shown passive alerts for hypokalaemia in the electronic health records. During the intervention period, in addition to these passive alerts, a pharmacist provided the physician with a specific advice on patients with untreated hypokalaemia, guided by the generated alerts. Unique patients >18 years with SPL <2.9 mmol/L measured at least 24 hours after hospitalization in whom no potassium supplementation was initiated within 4 hours after measurement and normalization of SPL was not achieved within these 4 hours were included. Haemodialysis patients were excluded. The percentage of hypokalaemic patients with a subsequent prescription for potassium supplementation, time to subsequent potassium supplementation prescription, the percentage of patients who achieved normokalaemia (SPL ≥ 3.0 mmol/L), time to achieve normokalaemia and total duration of hospitalization were compared.

RESULTS AND DISCUSSION

A total of 693 patients were included, of whom 278 participated in the intervention phase. The percentage of patients prescribed supplementation as well as time to prescription improved from 76.0% in 31.1 hours to 92.0% in 11.3 hours (P < .01). Time to achieve SPL ≥3.0 mmol/L improved, P < .009. No changes, however, were observed in the percentage of patients who achieved normokalaemia or time to reach normokalaemia, 87.5% in 65.2 hours pre-intervention compared to 90.2% (P = .69) in 64.0 hours (P = .71) in the intervention group. A non-significant decrease of 8.2 days was observed in the duration of hospitalization: 25.4 compared to 17.2 days (P = .29).

WHAT IS NEW AND CONCLUSION

Combining CDSS alerting with a pharmacist evaluation is an effective method to improve response rate, time to supplementation and time to initial improvement, defined as SPL ≥3.0 mmol/L. However, it showed no significant effect on the percentage of patients achieving normokalaemia, time to normokalaemia or hospitalization. The discrepancy between rapid supplementation and improvement on the one hand and failure to improve time to normokalaemia on the other warrants further study.

A U.S. Cost Analysis of Triplet Regimens for Patients with Previously Treated Multiple Myeloma

BACKGROUND

In recent years, the FDA has approved several 3-agent (i.e., triplet) combinations for previously treated multiple myeloma (MM), and the National Comprehensive Cancer Network (NCCN) now recommends triplet regimens over doublets. Little is known about the real-world cost of triplet combinations because of the limited time that they have been on the market since FDA approval. Furthermore, traditional cost analyses developed to support market entrance rely on utilization assumptions that are difficult to validate when numerous comparators simultaneously enter the market.

OBJECTIVE

To perform a 1-year cost analysis of novel triplets used for the treatment of patients with previously treated MM controlling for differences in utilization.

METHODS

FDA-approved, NCCN-recommended (preferred and category 1 for previously treated MM) treatments included in the analysis were daratumumab plus lenalidomide plus dexamethasone (DARA/LEN/DEX), daratumumab plus bortezomib plus dexamethasone (DARA/BOR/DEX), elotuzumab plus lenalidomide plus dexamethasone (ELO/LEN/DEX), carfilzomib plus lenalidomide plus dexamethasone (CAR/LEN/DEX), and ixazomib plus lenalidomide plus dexamethasone (IXA/LEN/DEX). To control for market uptake, the model was designed to estimate the cost of treating an average patient over a 1-year time horizon. Drug administration and dosing, required comedications, postprogression therapy, monitoring requirements, and adverse event (AE) rates were based on FDA prescribing information or clinical trials. AEs ≥ grade 3 that occurred in ≥ 5% of patients were included. RED BOOK wholesale acquisition costs were used for drug acquisition costs. Costs of drug administration, AE management, and patient monitoring were based on the 2018 Center for Medicare & Medicaid Services payment rates or from published literature (inflated to 2018 U.S. dollars). The treatment duration for each regimen was estimated from modeled progression-free survival data; the 12-month progression-free survival rate was assumed to be equivalent to the probability that an average patient remained on therapy for at least 1 year after treatment initiation, which was used to estimate time-depended treatment-related costs. The probability of progression within 1 year of treatment initiation was used to inform the average postprogression therapy costs for each regimen.

RESULTS

The estimated cost per patient for each triplet regimen was $13,890 (DARA/BOR/DEX), $22,231 (IXA/LEN/DEX), $24,322 (ELO/LEN/DEX), $26,410 (DARA/LEN/DEX), and $27,432 (CAR/LEN/DEX). Drug acquisition costs and treatment duration were the largest drivers of cost. Scenario analyses with plausible alternative input parameters found the maximum per month cost of therapy to be $30,657 (CAR/LEN/DEX) and the minimum per month cost of therapy to be $13,784 (DARA/BOR/DEX).

CONCLUSIONS

This analysis controlled for differential utilization rates for 5 FDA-approved, NCCN-recommended triplet therapies for the treatment of previously treated MM. Of the examined regimens, treatment with DARA/BOR/DEX was estimated to have the lowest average monthly cost per patient, while CAR/LEN/DEX was the most expensive. As is common with modeling, some assumptions were necessary, and results may not be generalizable.

DISCLOSURES

This study was funded by Janssen Scientific Affairs, which employs Maiese and funded Cornerstone Research Group, a health economic consulting group, to complete the cost analysis, interpret data, and develop the manuscript. Janssen was involved in the design of the analysis, interpretation of results, and manuscript development and approval. Grima is a founding partner of Cornerstone Research Group, which employs Hollmann, Goyert, and Moldaver. Hollmann, Goyert, and Moldaver were responsible for creation of the economic model. This work was peer-reviewed and presented as an abstract at the Lymphoma and Myeloma 2017 International Congress; October 26-28, 2017; New York, NY.

A retrospective analysis of postoperative hypokalemia in pituitary adenomas after transsphenoidal surgery

BACKGROUND

Pituitary adenoma is one of the most common intracranial neoplasms, and its primary treatment is endoscopic endonasal transsphenoidal tumorectomy. Postoperative hypokalemia in these patients is a common complication, and is associated with morbidity and mortality. This study aimed to analyze the etiopathology of postoperative hypokalemia in pituitary adenomas after endoscopic transsphenoidal surgery.

METHODS AND MATERIALS

This retrospective study included 181 pituitary adenomas confirmed by histopathology. Unconditional logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Repeated measures ANOVA was used to analyze change in serum potassium levels at different time points.

RESULTS

Multiple Logistic regression analysis revealed that only ACTH-pituitary adenoma (OR = 4.92, 95% CI [1.18-20.48], P = 0.029) had a significant association with postoperative hypokalemia. Moreover, the overall mean serum potassium concentration was significantly lower in the ACTH versus the non-ACTH group (3.34 mmol/L vs. 3.79 mmol/L, P = 0.001). Postoperative hypokalemia was predominantly found in patients with ACTH-pituitary adenoma (P = 0.033).

CONCLUSIONS

ACTH-pituitary adenomas may be an independent factor related postoperative hypokalemia in patients despite conventional potassium supplementation in the immediate postoperative period.

Hypokalaemia: Addressing human factors and improving education around prescription and administration of Intravenous(IV) Potassium infusion in Trauma and Orthopaedics

A high incidence of hypokalaemia was noted in Trauma and Orthopaedics of Ninewells Hospital. We sought to establish the reason behind this and implemented three PDSA cycles via questionnaires to 30 ward staff, both doctors and nurses over a 1 week period in December, February and July 2016. Key baseline measures include availability of IV fluids with 40mmol potassium on the wards, confidence prescribing or administering IV fluids with 40mmol potassium, necessity for cardiac monitoring during slow IV potassium replacement and recognition of confusion and learning need in this area. Interventions made include awareness and education session, departmental guideline, improving stock of IV fluids and hypokalaemia management pathway for mild, moderate and severe hypokalaemia. Post-intervention results showed 70% from 33% who said 40mmol IV potassium was available, 87% from 67% were confident prescribing or administering IV potassium and 70% from 27% were aware that cardiac monitoring was not necessary.