Laboratory monitoring of potassium and creatinine in ambulatory patients receiving angiotensin converting enzyme inhibitors and angiotensin receptor blockers

Potassium: A Frontier in Osteoporosis

Osteoporosis is a significant public health concern, particularly in aging populations, leading to fractures, decreased mobility, and reduced quality of life. While calcium and vitamin D have long been recognized as essential for bone health, emerging research suggests that potassium may play a crucial role in maintaining bone density and preventing osteoporosis. This manuscript explores the relationship between potassium and osteoporosis, delving into the mechanisms, epidemiological evidence, and potential therapeutic implications of potassium in bone health. Furthermore, the manuscript discusses the sources of dietary potassium, its impact on bone metabolism, and the future directions in research and clinical practice regarding potassium's role in osteoporosis management.

Pathophysiology and clinical management of hyperkalemia in chronic kidney disease

Adaptive increases in kidney and gastrointestinal excretion of K+ help to prevent hyperkalemia in patients with chronic kidney disease (CKD) as long as the glomerular filtration rate (GFR) remains >15-20 mL/min. K+ balance is maintained by increased secretion per functioning nephron, which is mediated by elevated plasma K+ concentration, aldosterone, increased flow rate, and enhanced Na+-K+-ATPase activity. Fecal losses of potassium also increase in CKD. These mechanisms are effective in preventing hyperkalemia if urine output is in excess of 600 mL/day and the GFR exceeds 15 mL/min. Development of hyperkalemia with only mild to moderate reductions in GFR should prompt a search for intrinsic disease of the collecting duct, disturbances in mineralocorticoid activity, and/or decreased delivery of sodium to the distal nephron. The initial approach to treatment is to review the patient's medication profile and whenever possible discontinue drugs that impair kidney K+ excretion. Patients should be educated on sources of K+ in the diet and should be strongly encouraged to avoid the use of K+ containing salt substitutes as well as herbal remedies since herbs may be a hidden source of dietary K+. Effective diuretic therapy and correction of metabolic acidosis are effective strategies to minimize the potential for hyperkalemia. Discontinuation or use of submaximal doses of renin-angiotensin blockers should be discouraged given the cardiovascular protective effect these drugs provide. Potassium binding drugs can be useful to enable use of these drugs and potentially allow liberalization of the diet in CKD patients.

Effects of angiotensin II receptor blockers on serum potassium level and hyperkalemia risk: retrospective single-centre analysis

OBJECTIVE

To examine the effect of angiotensin II receptor blocker (ARB) treatment on serum potassium level and hyperkalaemia risk in a clinical setting with inpatients and outpatients using calcium channel blockers (CCBs) as a reference standard.

METHODS

The increased risk of hyperkalaemia associated with ARB treatment is known, however only a few studies have used an active comparator to examine this risk. In this retrospective study at a 320-bed general hospital in Japan, the hospital information system was used to identify patients with at least one prescription for an ARB (819 patients) or a CCB (1015 patients) who were naive to these drugs before study initiation. Serum potassium levels before and after ARB treatment were compared. Additionally, the unadjusted and adjusted hazard ratios for the risk of hyperkalaemia in the ARB and CCB users were estimated.

RESULTS

The serum potassium level was higher in patients receiving ARB treatment (0.05 mEq/L, p=0.02) compared with those on CCB treatment. However, there was no significant association between ARB use and hyperkalaemia (adjusted HR 0.91, 95% CI 0.42 to 1.99, p=0.82).

CONCLUSION

The increase in serum potassium level after ARB initiation makes it necessary to monitor serum potassium levels continuously during ARB treatment; however, the risk of hyperkalaemia appeared to be similar for ARB and CCB treatments.

Adverse Events After Initiating Angiotensin-Converting Enzyme Inhibitor/Angiotensin II Receptor Blocker Therapy in Individuals with Heart Failure and Multimorbidity

BACKGROUND

Current clinical practice guidelines recommend routine kidney function and serum potassium testing within 30 days of initiating angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) therapy. However, evidence is lacking on whether routine follow-up testing reduces therapy-related adverse events in adults with heart failure and if multimorbidity influences the association between laboratory testing and these adverse events.

METHODS

We conducted a retrospective cohort study among adults with heart failure from 4 US integrated health care delivery systems. Multimorbidity was defined using counts of chronic conditions. Patients with outpatient serum creatinine and potassium tests in the 30 days after starting ACEI or ARB therapy were matched 1:1 to patients without follow-up tests. We evaluated the association of follow-up testing with 30-day all-cause mortality and hospitalization with acute kidney injury or hyperkalemia using Cox regression.

RESULTS

We identified 3629 matched adults with heart failure initiating ACEI or ARB therapy between January 1, 2005, and December 31, 2012. Follow-up testing was not significantly associated with 30-day all-cause mortality (adjusted hazard ratio [aHR] 0.45, 95% confidence interval [CI] 0.14; 1.39) and hospitalization with hyperkalemia (aHR 0.73, 95% CI, 0.33; 1.61). However, follow-up testing was significantly associated with hospitalization with acute kidney injury (aHR, 1.40, 95% CI, 1.01; 1.94). Interaction between multimorbidity burden and follow-up testing was not statistically significant in any of the outcome models examined.

CONCLUSIONS

Routine laboratory monitoring after ACEI or ARB therapy initiation was not associated with risk of 30-day all-cause mortality or hospitalization with hyperkalemia across the spectrum of multimorbidity burden in a cohort of patients with heart failure.

Pragmatic Diagnostic and Therapeutic Algorithms to Optimize New Potassium Binder use in Cardiorenal Disease

BACKGROUND

Pivotal randomized trials demonstrating efficacy, safety and good tolerance, of two new potassium binders (patiromer and sodium zirconium cyclosilicate) led to their recent approval. A major hurdle to the implementation of these potassium-binders is understanding how to integrate them safely and effectively into the long-term management of cardiovascular and kidney disease patients using renin angiotensin aldosterone system inhibitors (RAASi), the latter being prone to induce hyperkalaemia.

METHODS

a multidisciplinary academic panel including nephrologists and cardiologists was convened to develop consensus therapeutic algorithm(s) aimed at optimizing the use of the two novel potassium binders (patiromer and sodium zirconium cyclosilicate) in stable adults who require treatment with RAASi and experience(d) hyperkalaemia in a non-emergent setting.

RESULTS

Two dedicated pragmatic algorithms are proposed. The lowest intervention threshold (i.e. 5.1mmol/L or greater) was the one used in the patiromer and sodium zirconium cyclosilicate) pivotal trials, both drugs being indicated to treat hyperkalaemia in a non -emergent setting. Acknowledging the heterogeneity across specialty guidelines in hyperkalaemia definition and thresholds to intervene when facing hyperkalaemia, we have been mindful to use soft language i.e. "it is to consider", not necessarily "to do".

CONCLUSIONS

Providing the clinical community with pragmatic algorithms may help optimize the management of high-risk patients by avoiding the risks of both hyper and hypokalaemia and of suboptimal RAASi therapy.

Laboratory monitoring to reduce adverse drug-related events: a mixed methods study

BACKGROUND: Therapy with angiotensinconverting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) requires laboratory monitoring to avoid hyperkalemia and acute kidney failure. OBJECTIVE: To assess the frequency of recommended annual serum potassium and creatinine monitoring and determine potential factors associated with care gaps among adults dispensed an ACEI or ARB. METHODS: This mixed-methods study integrated findings from a retrospective cohort study and individual patient interviews. Adults aged 21 years and over within Kaiser Permanente Southern California with at least 180 treatment days of an ACEI and/or ARB in 2015 were included. Patients invited for qualitative interviews included those who did and did not complete the recommended laboratory tests. We assessed the proportion of patients completing both recommended laboratory tests, factors associated with not receiving laboratory monitoring, and patients' insights into barriers and facilitators of recommended monitoring. RESULTS: Of 437,544 patients who received an ACEI or ARB, 9.0% did not receive both a serum potassium and creatinine laboratory test during treatment (defined as a care gap). Lower risk of a care gap was observed for patients with increasing age (rate ratio [RR] per 10-year increase = 0.78, 95% CI = 0.77-0.79); diabetes mellitus (RR = 0.62, 95% CI = 0.60-0.64); hypertension (RR = 0.71, 95% CI = 0.71-0.74); Charlson Comorbidity Index score of at least 2 (RR = 0.62, 95% CI = 0.60-0.64); those who changed medication classes (RR = 0.53, 95% CI = 0.51-0.56); and patients with a cardiologist (RR = 0.81, 95% CI = 0.73-0.90) or nephrologist (RR = 0.60, 95% CI = 0.52-0.69) as their prescribing provider. Twenty-five patients completed the qualitative interviews. Patients often lacked knowledge about the need for laboratory monitoring, cited logistical barriers to accessing the laboratory, and deemed the reminders they received through an outpatient safety program as a facilitator to completing tests. CONCLUSIONS: Given the large patient population on ACEI and ARB medications, monitoring and support strategies such as electronic clinical surveillance could be important in addressing care gaps and potentially reducing adverse drug effects. DISCLOSURES: This project was supported by grant number R01HS024437 from the Agency for Healthcare Research and Quality. The funder had no role in the design of the study; collection, analyses, or interpretation of the data, or decision to submit this manuscript for publication. Harrison, Reynolds, Hahn, Munoz-Plaza, Yi, Fischer, Luong, Sim, Brettler, Handler, and Mittman are employees of the Southern California Permanente Medical Group. Danworth was employed by the Southern California Permanente Medical Group at the time of this study. Singh was partially supported by the Houston VA HSR&D Center for Innovations in Quality, Effectiveness and Safety (CIN13-413). Reynolds reports grants from Novartis, Amgen Inc., and Vital Strategies, Resolve to Save Lives, unrelated to this work. Yi reports grants from Novartis unrelated to this work. Kanter has nothing to disclose.

DNA Aptamer Functionalized Hydrogels for Interferometric Fiber-Optic Based Continuous Monitoring of Potassium Ions

In the present paper, we describe a potassium sensor based on DNA-aptamer functionalized hydrogel, that is capable of continuous label-free potassium ion (K+) monitoring with potential for in situ application. A hydrogel attached to the end of an optical fiber is designed with di-oligonucleotides grafted to the polymer network that may serve as network junctions in addition to the covalent crosslinks. Specific affinity toward K+ is based on exploiting a particular aptamer that exhibits conformational transition from single-stranded DNA to G-quadruplex formed by the di-oligonucleotide in the presence of K+. Integration of this aptamer into the hydrogel transforms the K+ specific conformational transition to a K+ concentration dependent deswelling of the hydrogel. High-resolution interferometry monitors changes in extent of swelling at 1 Hz and 2 nm resolution for the hydrogel matrix of 50 µm. The developed hydrogel-based biosensor displayed high selectivity for K+ ions in the concentration range up to 10 mM, in the presence of physiological concentrations of Na+. Additionally, the concentration dependent and selective K+ detection demonstrated in the artificial blood buffer environment, both at room and physiological temperatures, suggests substantial potential for practical applications such as monitoring of potassium ion concentration in blood levels in intensive care medicine.

Onset of Hyperkalemia following the Administration of Angiotensin-Converting Enzyme Inhibitor or Angiotensin II Receptor Blocker

Introduction

In spite of the established importance of detecting angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker- (ARB-) induced hyperkalemia, there have not been many studies on the time of its occurrence.

Methods

We retrospectively analyzed electronic medical records to determine the onset time and incidence rate of hyperkalemia (serum potassium > 5.5 mEq/L or 6.0 mEq/L) among hospitalized patients newly started on a 15-day ACEI or ARB therapy.

Results

Among 3101 hospitalized patients, hyperkalemia incidence was 0.5%–0.9% and 0.8%–2.1% in the ACEI and ARB groups, respectively. However, it was not significantly different among different ARB types. Hyperkalemia's onset was distributed throughout 15 days, without any trend. Hyperkalemia incidence was 7.3 and 35.1 times higher at 5.5 mEq/L (hazard ratio (HR) = 7.31, 95%confidence interval (CI) = 4.19–12.76, p < 0.001) and 6.0 mEq/L (HR = 35.11, 95%CI = 8.25–149.52, p < 0.001), respectively, than the baseline creatinine level. Hyperkalemia incidence in patients with chronic renal failure was 5.7 and 9.2 times higher at 5.5 mEq/L (HR = 5.72, 95%CI = 3.24–10.12, p < 0.001) and 6.0 mEq/L (HR = 9.16, 95%CI = 4.02–20.88, p < 0.001), respectively.

Conclusions

It is unlikely that it is necessary to monitor hyperkalemia immediately after administration of ACEI or ARB. However, when prescribed for patients with abnormal kidney function, clinicians should always consider the possibility of developing hyperkalemia.

Effects of hyperkalaemia and non-adherence to renin-angiotensin-aldosterone system inhibitor therapy in patients with heart failure in Italy: a propensity-matched study

Aims

The aims of this study were to evaluate if the risk of cardiovascular events and all‐cause mortality was higher in the presence of hyperkalaemia (HK) in patients with heart failure (HF) treated with renin–angiotensin–aldosterone system inhibitors (RAASi), and to investigate in this cohort the increased risk of cardiovascular events and all‐cause mortality among HK patients with non‐optimal adherence to RAASi therapy.

Methods and results

In this retrospective cohort study based on administrative databases of five Italian Local Health Units, all adult patients with a HF diagnosis between January 2010 and December 2017 were included only if they were prescribed RAASi therapy during the first 3 months after the index date, that corresponded to the date of first HF diagnosis during the inclusion period. Patients were considered to have HK if serum potassium level was ≥5.5 mmol/L. A propensity score matching was applied before evaluation of hazard ratios. Patients with HK were 37% (P < 0.001) and 70% (P < 0.001), respectively, more at risk of cardiovascular events and of dying for all‐cause mortality compared to non‐HK patients. Among the HK group, patients non‐adherent to RAASi therapy had a 39% (P = 0.105) higher risk of cardiovascular events and a twofold increased risk (P < 0.001) of all‐cause death.

Conclusion

Findings from this real‐world study showed that in a cohort of HF patients under RAASi therapy, subjects with HK had an enhanced risk of cardiovascular events or death compared to patients without HK. Moreover, in HK patients, sub‐optimal adherence to RAASi therapy was associated with an increased risk of all‐cause mortality.

Frequency of laboratory testing and associated abnormalities in patients with hypertension

Clinical practice guidelines recommend several routine laboratory tests in patients diagnosed with hypertension. However, the rates of clinically relevant laboratory abnormalities are unknown. Therefore, we conducted a retrospective cohort study using administrative and laboratory data of patients diagnosed with hypertension between April 2010 and March 2015 in Alberta, Canada. Laboratory investigations for renal function, serum electrolytes (sodium and potassium), low-density lipoprotein (LDL) cholesterol, and diabetes (fasting blood glucose and hemoglobin A1c), measured within 1 year of diagnosis, were examined, and the frequency of abnormalities determined. A total of 225 296 cases of incident hypertension were identified. Of these, 74.3% received at least one of the four guideline-recommended laboratory tests, but only 42.3% received all four tests. Patients who received any testing, compared to subjects who did not, were on average older (median age 55.9 vs 51.2 years, P < .001) and had more comorbidity (14.5% vs 2.8% with a Charlson comorbidity index ≥ 3, P < .001). Laboratory abnormalities with the potential to affect clinical decision-making were more common among multi-comorbid patients. Patients with renal dysfunction (6.7% vs 11.6%, 26.3%, P < .001), electrolyte abnormalities (9.8% vs 12.6%, 20.5%, P < .001), and diabetes (13.4% vs 25.1% vs 38.8%, P < .001) were found in patients with Charlson scores of 0 vs 1-2 vs ≥3, respectively. Our study found most patients diagnosed with hypertension received some laboratory testing, but rates of laboratory testing and frequency of abnormalities varied by clinical context. Testing and abnormalities detected were both more common among older patients and patients with comorbidities.

Kidney Function and Potassium Monitoring After Initiation of Renin-Angiotensin-Aldosterone System Blockade Therapy and Outcomes in 2 North American Populations

BACKGROUND

Clinical practice guidelines recommend routine kidney function and serum potassium testing within 30 days of initiating ACE (angiotensin-converting enzyme) inhibitor or angiotensin II receptor blocker therapy. However, evidence is lacking about whether follow-up testing reduces therapy-related adverse outcomes.

METHODS AND RESULTS

We conducted 2 population-based retrospective cohort studies in Kaiser Permanente Northern California and Ontario, Canada. Patients with outpatient serum creatinine and potassium tests in the 30 days after starting ACE inhibitor or angiotensin II receptor blocker therapy were matched 1:1 to patients without follow-up tests. We evaluated the association of follow-up testing with 30-day all-cause mortality and hospitalization with acute kidney injury or hyperkalemia using Cox regression. We also developed and externally validated a risk score to identify patients at risk of having abnormally high serum creatinine and potassium values in follow-up. We identified 75 251 matched pairs initiating ACE inhibitor or angiotensin II receptor blocker therapy between January 1, 2007, and December 31, 2017, in Kaiser Permanente Northern California. Follow-up testing was not significantly associated with 30-day all-cause mortality in Kaiser Permanente Northern California (hazard ratio, 0.75 [95% CI, 0.54-1.06]) and was associated with higher mortality in 84 905 matched pairs in Ontario (hazard ratio, 1.32 [95% CI, 1.07-1.62]). In Kaiser Permanente Northern California, follow-up testing was significantly associated with higher rates of hospitalization with acute kidney injury (hazard ratio, 1.66 [95% CI, 1.10-2.22]) and hyperkalemia (hazard ratio, 3.36 [95% CI, 1.08-10.41]), as was observed in Ontario. The risk score for abnormal potassium provided good discrimination (area under the curve [AUC], 0.75) and excellent calibration of predicted risks, while the risk score for abnormal serum creatinine provided moderate discrimination (AUC, 0.62) but excellent calibration.

CONCLUSIONS

Routine laboratory monitoring after ACE inhibitor or angiotensin II receptor blocker initiation was not associated with a lower risk of 30-day mortality. We identified patient subgroups in which targeted testing may be effective in identifying therapy-related changes in serum potassium or kidney function.

Hyperkalemia and Renin-Angiotensin-Aldosterone System Inhibitors Dose Therapy in Heart Failure With Reduced Ejection Fraction

Renin-angiotensin-aldosterone system inhibitors (RAASi) are known to improve outcomes in patients who have heart failure with reduced ejection fraction (HFrEF). To reduce mortality in these patients, RAASi should be uptitrated to the maximally tolerated dose. However, RAASi may also cause hyperkalemia. As a result of this side-effect, doses of RAASi are reduced, discontinued and seldom reinstated. Thus, the therapeutic target needed in these patients is often not reached because of hyperkalemia. Also, submaximal dosing of RAASi may be a result of symptomatic hypotension, syncope, hypoperfusion, reduced kidney function and other factors. The reduction of RAASi dose leads to adverse outcomes, such as an increased risk of mortality. Management of these side-effects is pivotal to maximise the use of RAASi in HFrEF, particularly in high-risk patients.

Can we predict who will develop postoperative hyperkalaemia after parathyroidectomy in dialysis patients with secondary hyperparathyroidism?

BACKGROUND

Hyperkalaemia occurs frequently in many maintenance haemodialysis (MHD) patients after parathyroidectomy (PTX) with secondary hyperparathyroidism (SHPT). However, the clinical risk factors that predict postoperative hyperkalaemia are uncertain.

METHODS

This retrospective cohort study included 90 maintenance haemodialysis patients aged ≥18 years who underwent PTX between April 2011 and April 2016 at Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine). Pre- and post-PTX surgery venous samples were measured in quadruplicate. We examined univariate associations with demographics, dialysis characteristics, laboratory values and medications. Hyperkalaemia was defined as serum potassium >5.3 mmol/L.

RESULTS

Out of nighty patients, twenty-two (24.4%) developed postoperative hyperkalaemia, of whom sixteen (18.1%) developed hyperkalaemia on postoperative day 3. The univariate analysis showed that weight, dialysis duration, preoperative serum potassium, alkaline phosphate, triglyceride, and postoperative alkaline phosphate were independently associated with hyperkalaemia after parathyroidectomy. The univariate logistic regression model showed that preoperative serum potassium was the only independent factor that could predict hyperkalaemia after parathyroidectomy (odds ratio, 1.59; 95% confidence interval, 1.24-2.05). The optimal cut-off for pre-operative K was 3.9 mmol/L according to the receiver operating characteristic (ROC) curve. A higher incidence of postoperative hyperkalaemia was found in male and younger patients, but the difference was not statistically significant (p>0.05).

CONCLUSIONS

Pre-operative serum potassium less than 3.9 mmol/L was associated with less hyperkalaemia post-operatively in end-stage renal disease (ESRD) patients undergoing PTX.

Structure and Content of Drug Monitoring Advices Included in Discharge Letters at Interfaces of Care: Exploratory Analysis Preceding Database Development

BACKGROUND

Inadequate drug monitoring of drug therapy after hospital discharge facilitates adverse drug events and preventable hospital readmissions.

OBJECTIVE

This study aimed to analyze the structure and content of drug monitoring advices of a representative sample of discharge letters as a basis for future electronic information systems.

METHODS

On 2 days in November 2016, all discharge letters of 3 departments of a university hospital were extracted from the hospital information system. The frequency, content, and structure of drug monitoring advices in discharge letters were investigated and compared with the theoretical monitoring requirements expressed in the corresponding summaries of product characteristics (SmPC). The quality of the drug monitoring advices in the discharge letters was rated with the domains of an adapted systematic instructions for monitoring (SIM) score.

RESULTS

In total, 154 discharge letters were analyzed containing 1180 brands (240 active pharmaceutical substances), of which 50.42% (595/1180) could theoretically be amended with a monitoring advice according to the SmPC. In reality, 40 discharge letters (26.0%, 40/154) contained a total of 66 monitoring advices for 57 brands (4.83%, 57/1180), comprising 18 different monitoring parameters. Drug monitoring advices only addressed mean 1.9 (SD 0.8) of the 7 domains of the SIM score and frequently did not address reasons for monitoring (86%, 57/66), the timing of monitoring, that is, the start (76%, 50/66), the frequency (94%, 63/66), the stop (95%, 63/66), and how to react (83%, 55/66).

CONCLUSIONS

Drug monitoring advices were mostly absent in discharge letters and a gold standard for appropriate drug monitoring advices was lacking. Hence, more effort should be put in the development of tools that facilitate easy presentation of clinically meaningful drug monitoring advices at the point of care.

Potassium homeostasis in health and disease: A scientific workshop cosponsored by the National Kidney Foundation and the American Society of Hypertension

While much emphasis, and some controversy, centers on recommendations for sodium intake, there has been considerably less interest in recommendations for dietary potassium intake, in both the general population and patients with medical conditions, particularly acute and chronic kidney disease. Physiology literature and cohort studies have noted that the relative balance in sodium and potassium intakes is an important determinant of many of the sodium-related outcomes. A noteworthy characteristic of potassium in clinical medicine is the extreme concern shared by many practitioners when confronted by a patient with hyperkalemia. Fear of this often asymptomatic finding limits enthusiasm for recommending potassium intake and often limits the use of renin-angiotensin-aldosterone system blockers in patients with heart failure and chronic kidney diseases. New agents for managing hyperkalemia may alter the long-term management of heart failure and the hypertension, proteinuria, and further function loss in chronic kidney diseases. In this jointly sponsored effort between the American Society of Hypertension and the National Kidney Foundation, 3 panels of researchers and practitioners from various disciplines discussed and summarized current understanding of the role of potassium in health and disease, focusing on cardiovascular, nutritional, and kidney considerations associated with both hypo- and hyperkalemia.

Potassium Homeostasis in Health and Disease: A Scientific Workshop Cosponsored by the National Kidney Foundation and the American Society of Hypertension

While much emphasis, and some controversy, centers on recommendations for sodium intake, there has been considerably less interest in recommendations for dietary potassium intake, in both the general population and patients with medical conditions, particularly acute and chronic kidney disease. Physiology literature and cohort studies have noted that the relative balance in sodium and potassium intakes is an important determinant of many of the sodium-related outcomes. A noteworthy characteristic of potassium in clinical medicine is the extreme concern shared by many practitioners when confronted by a patient with hyperkalemia. Fear of this often asymptomatic finding limits enthusiasm for recommending potassium intake and often limits the use of renin-angiotensin-aldosterone system blockers in patients with heart failure and chronic kidney diseases. New agents for managing hyperkalemia may alter the long-term management of heart failure and the hypertension, proteinuria, and further function loss in chronic kidney diseases. In this jointly sponsored effort between the American Society of Hypertension and the National Kidney Foundation, 3 panels of researchers and practitioners from various disciplines discussed and summarized current understanding of the role of potassium in health and disease, focusing on cardiovascular, nutritional, and kidney considerations associated with both hypo- and hyperkalemia.

Treatment of Abnormalities of Potassium Homeostasis in CKD

Hyperkalemia, defined as serum potassium concentrations greater than 5.0 to 5.5 mEq/L, is a frequent occurrence in clinical practice because of the increasing incidence and prevalence of CKD. Patients at risk for this disorder are commonly treated with drugs that interfere in the renin-angiotensin-aldosterone system, thereby enhancing the occurrence and prevalence of this disorder. Discontinuation of these drugs because of the development of hyperkalemia deprives these patients the renal-protective and cardiovascular benefits this class of pharmacology has been shown to provide. Here we provide the clinician strategies to both prevent and treat hyperkalemia in patients with CKD who are prescribed these drugs. We emphasize the importance of limiting dietary potassium intake and avoiding either prescribed or over-the-counter medications that may impair renal potassium excretion. We discuss the role of kaliuretic diuretics and correction of metabolic acidosis as a therapeutic strategy. Additionally, we discuss the role of new agents designed to bind potassium in the gastrointestinal tract that can be used to maintain normokalemia in patients who previously developed hyperkalemia on renin-angiotensin-aldosterone blockers. Finally, we provide a brief discussion on how best to treat hypokalemia in patients with CKD.

Hyperkalemia After Initiating Renin-Angiotensin System Blockade: The Stockholm Creatinine Measurements (SCREAM) Project

BACKGROUND

Concerns about hyperkalemia limit the use of angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs), but guidelines conflict regarding potassium-monitoring protocols. We quantified hyperkalemia monitoring and risks after ACE-I/ARB initiation and developed and validated a hyperkalemia susceptibility score.

METHODS AND RESULTS

We evaluated 69 426 new users of ACE-I/ARB therapy in the Stockholm Creatinine Measurements (SCREAM) project with medication initiation from January 1, 2007 to December 31, 2010, and follow-up for 1 year thereafter. Three fourths (76%) of SCREAM patients had potassium checked within the first year. Potassium >5 and >5.5 mmol/L occurred in 5.6% and 1.7%, respectively. As a comparison, we propensity-matched new ACE-I/ARB users to 20 186 new β-blocker users in SCREAM: 64% had potassium checked. The occurrence of elevated potassium levels was similar between new β-blocker and ACE-I/ARB users without kidney disease; only at estimated glomerular filtration rate <60 mL/min per 1.73 m² were risks higher among ACE-I/ARB users. We developed a hyperkalemia susceptibility score that incorporated estimated glomerular filtration rate, baseline potassium level, sex, diabetes mellitus, heart failure, and the concomitant use of potassium-sparing diuretics in new ACE-I/ARB users; this score accurately predicted 1-year hyperkalemia risk in the SCREAM cohort (area under the curve, 0.845, 95% CI: 0.840-0.869) and in a validation cohort from the US-based Geisinger Health System (N=19 524; area under the curve, 0.818, 95% CI: 0.794-0.841), with good calibration.

CONCLUSIONS

Hyperkalemia within the first year of ACE-I/ARB therapy was relatively uncommon among people with estimated glomerular filtration rate >60 mL/min per 1.73 m², but rates were much higher with lower estimated glomerular filtration rate. Use of the hyperkalemia susceptibility score may help guide laboratory monitoring and prescribing strategies.

Mineralocorticoid receptor antagonist pattern of use in heart failure with reduced ejection fraction: findings from BIOSTAT-CHF

AIMS

Mineralocorticoid receptor antagonists (MRAs) are recommended (unless contraindicated) to all patients with heart failure with reduced ejection fraction (HFrEF). However, MRAs are still largely underused in routine clinical practice. This study aims to describe the determinants and pattern of use of MRAs in HFrEF.

METHODS AND RESULTS

BIOSTAT-CHF is a European multicentre, prospective study which enrolled patients suboptimally treated with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARBs) and/or beta-blockers, with the aim of optimizing guideline-based use of these agents. From the original 2516 subjects, this retrospective post hoc analysis included the 1325 patients with an indication for MRA therapy (i.e. left ventricular ejection fraction ≤35%, estimated glomerular filtration rate ≥30 mL/min/1.73 m² , K⁺ ≤5.0 mmol/L). The mean age was 66.1 ± 12.2 years. At baseline an MRA was prescribed to 741 (56%) patients. Patients who were prescribed MRAs at baseline were younger, more often male, had higher body mass index, lower sodium, higher proportion of hypertension history and ACEi/ARB prescription (all P < 0.05). Of the 1049 patients who completed the baseline plus the 9 month visit, 585 (56%) had an MRA prescribed at baseline and 662 (63%) had an MRA prescribed at 9 months. Among the 585 patients with MRA at baseline, 91 (16%) had discontinued therapy and among the 461 (44%) patients without MRA at baseline 168 (36%) had initiated therapy subsequently. MRA discontinuation was more likely in subjects with higher left ventricular ejection fraction and NYHA class III/IV (P < 0.05 for both). MRA prescription both at baseline and 9 months was not associated with the outcome of death or heart failure hospitalization (adjusted hazard ratio 1.02, 95% confidence interval 0.66-1.58; P = 0.93).

CONCLUSIONS

In this prospective observational study across Europe, MRAs were largely under-prescribed and frequently discontinued. Owing to these dynamic changes, outcome inferences are inconclusive.

Safe use of NSAIDs and RAS-inhibitors at Agogo Presbyterian Hospital, Ghana

BACKGROUND

Preventable adverse events of medication are an important cause of hospital admissions in the developed world, in which non-steroidal anti-inflammatory drugs (NSAIDs) and renin-angiotensin system (RAS-) inhibitors are frequently involved. NSAIDs and RAS-inhibitors are also often used in Ghana. The purpose of this study is to assess whether biochemical monitoring in patients on RAS-inhibitors, and co-administration of gastro protective agents (GPAs) in patients on NSAIDs, is done properly in Ghana.

MATERIAL AND METHODS

Two retrospective cross-sectional studies were carried out at the Agogo Presbyterian Hospital, Ghana, in 2013. In 114 out-and inpatients who are on NSAIDs, the risk for gastrointestinal side effects and the frequency of co-administration of GPAs were determined. In 301 outpatients who are on RAS-inhibitors, the risk for renal dysfunction and the frequency of biochemical monitoring were determined. Fisher's exact test was used to determine the statistical strength.

RESULTS

Co-administration of GPAs was done in 1.8% of patients on NSAIDs. Serum creatinine and potassium monitoring within one month after initiation of treatment with RAS-inhibitors were performed in 6.3% and 3.7%, respectively. Risk factors were neither associated with prescription of a GPA in patients on NSAIDs (p=0.134), nor in performing biochemical monitoring in patients on RAS-inhibitors (p=0.219 for creatinine, p=0.062 for potassium).

CONCLUSIONS

Biochemical monitoring in patients on RAS-inhibitors and use of GPAs in patients on NSAIDs is poorly performed at the Agogo Presbyterian Hospital in Ghana. Improving the already existing Ghanaian guidelines, especially those for RAS-inhibitors, and encouraging their widespread use among prescribers should be pursued.

Methods for using clinical laboratory test results as baseline confounders in multi-site observational database studies when missing data are expected

PURPOSE

Our purpose was to quantify missing baseline laboratory results, assess predictors of missingness, and examine performance of missing data methods.

METHODS

Using the Mini-Sentinel Distributed Database from three sites, we selected three exposure-outcome scenarios with laboratory results as baseline confounders. We compared hazard ratios (HRs) or risk differences (RDs) and 95% confidence intervals (CIs) from models that omitted laboratory results, included only available results (complete cases), and included results after applying missing data methods (multiple imputation [MI] regression, MI predictive mean matching [PMM] indicator).

RESULTS

Scenario 1 considered glucose among second-generation antipsychotic users and diabetes. Across sites, glucose was available for 27.7-58.9%. Results differed between complete case and missing data models (e.g., olanzapine: HR 0.92 [CI 0.73, 1.12] vs 1.02 [0.90, 1.16]). Across-site models employing different MI approaches provided similar HR and CI; site-specific models provided differing estimates. Scenario 2 evaluated creatinine among individuals starting high versus low dose lisinopril and hyperkalemia. Creatinine availability: 44.5-79.0%. Results differed between complete case and missing data models (e.g., HR 0.84 [CI 0.77, 0.92] vs. 0.88 [0.83, 0.94]). HR and CI were identical across MI methods. Scenario 3 examined international normalized ratio (INR) among warfarin users starting interacting versus noninteracting antimicrobials and bleeding. INR availability: 20.0-92.9%. Results differed between ignoring INR versus including INR using missing data methods (e.g., RD 0.05 [CI -0.03, 0.13] vs 0.09 [0.00, 0.18]). Indicator and PMM methods gave similar estimates.

CONCLUSION

Multi-site studies must consider site variability in missing data. Different missing data methods performed similarly. Copyright © 2016 John Wiley & Sons, Ltd.

Antihypertensive Medications and the Prevalence of Hyperkalemia in a Large Health System

Little is known about the frequency and patterns of hyperkalemia in clinical settings. We evaluated the association between baseline antihypertensive medications that may affect potassium levels (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, loop/thiazide diuretics, and potassium-sparing diuretics) and hyperkalemia, defined by potassium >5 mEq/L and >5.5 mEq/L, over a 3-year time period in 194 456 outpatients in the Geisinger Health System, as well as actions taken after an episode of hyperkalemia. The proportions of patients with 0, <2, 2 to 4, and ≥4 potassium measurements per year were 20%, 58%, 16%, and 6%. Potassium levels >5 mEq/L and >5.5 mEq/L occurred in 10.8% and 2.3% of all patients over the 3-year period; among patients with ≥4 measurements per year, corresponding values were 39.4% and 14.6%. Most cases of hyperkalemia occurred only once during follow-up. The antihypertensive medication class most strongly associated with hyperkalemia was angiotensin-converting enzyme inhibitors. Among patients with a measurement of potassium >5.5 mEq/L, only 24% were seen by a nephrologist and 5.2% were seen by a dietician during the 3-year period. Short-term actions after a potassium measurement >5.5 mEq/L included emergency room visit (3.1% within 7 days), remeasurement of potassium (44.3% with 14 days), and change in a potassium-altering medication (26.4% within 60 days). The most common medication changes were discontinuation/dose reduction of an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker or potassium-sparing diuretic, which occurred in 29.1% and 49.6% of people taking these medications, respectively. In conclusion, hyperkalemia is common. Future research may enable optimal renin-angiotensin-aldosterone system inhibitor use with improved management of hyperkalemia.

Appropriate baseline laboratory testing following ACEI or ARB initiation by Medicare FFS beneficiaries

BACKGROUND

Laboratory testing to identify contraindications and adverse drug reactions is important for safety of patients initiating angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs). Rates and predictors of appropriate testing among Medicare fee-for-service beneficiaries are unknown.

PURPOSE

The study's purpose was to examine baseline laboratory testing rates, identify predictors of suboptimal testing, and assess the prevalence of abnormal creatinine and potassium among beneficiaries initiating ACE inhibitors or ARBs.

DESIGN AND SUBJECTS

Retrospective cohort of 101 376 fee-for-service beneficiaries from 10 eastern US states in 1 July to 30 November 2011.

MAIN MEASURES

Appropriate monitoring for serum creatinine or serum potassium was defined as evidence of an outpatient claim within 180 days before or 14 days after the index prescription fill date.

KEY RESULTS

Thirty-eight percent of beneficiaries were men, 78% were White race, 26% had prevalent heart failure, and 89% had prevalent hypertension. Rates of appropriate baseline laboratory testing were 82.7% for potassium, 83.2% for creatinine, and 82.6% for both potassium and creatinine 180 days prior to initiation. In logistic regression, men (odds ratio [OR] = 1.15, 95% confidence interval [CI]: 1.11, 1.19), African-Americans (OR = 1.26, 95%CI: 1.20, 1.32), and beneficiaries with Alzheimer's disease and related disorders (OR = 1.22, 95%CI: 1.15, 1.28) or stroke (OR = 1.34, 95%CI: 1.26, 1.43) were more likely to experience suboptimal testing. At baseline, hyperkalemia was relatively uncommon (5.8%), and elevated creatinine values were rare (1.4%).

CONCLUSIONS

Appropriate monitoring could be improved for African-American beneficiaries and beneficiaries with a history of stroke or Alzheimer's disease and related disorders initiating ACE inhibitors or ARBs. Copyright © 2016 John Wiley & Sons, Ltd.

Linkage of Laboratory Results to Medicare Fee-for-Service Claims

BACKGROUND

Medicare is the single largest purchaser of laboratory testing in the United States, yet test results associated with Medicare laboratory claims have historically not been available.

OBJECTIVE

The purpose of this study was to describe both the linkage of laboratory results data to Medicare claims and the completeness of these results data. In a subgroup of beneficiaries initiating angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, we also demonstrate the generalizability of Medicare beneficiaries with laboratory values compared with those without laboratory values. We end with a discussion of the limitations and potential uses of these linked data.

METHODS

We obtained information about laboratory orders and results for all Medicare fee-for-service beneficiaries in 10 eastern states who had outpatient laboratory tests conducted by a large national laboratory services vendor in 2011. Using a combination of direct identifiers and patient demographic characteristics, we linked patients in these laboratory data to Medicare beneficiaries, enabling us to associate test results with existing claims.

RESULTS

Nearly all patients in the laboratory data were able to be linked to Medicare beneficiaries. There were over 2 million distinct beneficiaries with nearly 125 million specific test results in the laboratory data. For specific tests ordered in an outpatient or office setting in these 10 states, between 5% and 15% of them had linked laboratory data. Medicare beneficiaries initiating angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers who had laboratory results data had similar patient characteristics to those without results data.

CONCLUSIONS

This novel linkage of laboratory results data to Medicare claims creates unprecedented opportunities for conducting comparative effectiveness research related to patient safety and quality.

Development of a medication monitoring attitude measure using a mixed methods item development process

Objectives

Medication monitoring is important for safe and effective medication use; however, no attitudinal measure exists for a health care provider's medication monitoring attitude. The objectives of this study were to (1) create a measure of a community pharmacist medication monitoring attitude; (2) test concurrent validity using a validated measure of medication monitoring behaviours; and (3) report community pharmacist attitudes towards medication monitoring.

Methods

A mixed methods item development process was employed to generate Likert-type items from qualitative interviews. Following item review and piloting, a four-contact survey, including 20 6-point Likert-type items and the four-item Behavioral Pharmaceutical Care Scale monitoring domain, was mailed to 599 randomly sampled US community pharmacists from the state of Iowa. Exploratory factor analysis, Pearson's correlation and descriptive statistics were used to address study objectives.

Key findings

There were 254 (42.4%) returned and usable surveys. Factor analysis yielded two domains, a seven-item, positively worded internal (α = 0.819) and an eight-item, negatively worded external domain (α = 0.811). Both domains were positively correlated with the monitoring domain of the Behavioral Pharmaceutical Care Scale supporting convergent validity. Overall, respondents had a positive internal monitoring attitude with a mean of 4.62 (0.68), although many practiced in an environment less conducive to monitoring, as evident by a mean of 3.13 (0.88). Pharmacists were more oriented towards medication side effect and effectiveness monitoring than nonadherence monitoring.

Conclusions

The mixed methods item development process created a reliable and valid measure of a pharmacist's medication monitoring attitude. While pharmacists had an overall positive medication monitoring attitude, improvements are needed to bolster adherence monitoring and make pharmacy environments more conducive to monitoring.

Adherence to renal function monitoring guidelines in patients starting antihypertensive therapy with diuretics and RAAS inhibitors: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) might complicate antihypertensive therapy. In The Netherlands, general practitioner clinical practice guidelines provide clear recommendations on monitoring of renal function to minimize this risk. Our objective was to investigate how day-to-day clinical practice corresponds to the guidelines.

METHODS

We conducted a retrospective cohort study in a dynamic population, using data on >9,000 adults that was retrieved from the Integrated Primary Care Information database. We investigated whether serum creatinine (SCR) was measured within 30 and 365 days after the start of (combined) use of a diuretic, an angiotensin-converting enzyme inhibitor, and/or angiotensin receptor blocker. We also investigated the association between calendar year, sex, type of therapy, risk factors for AKI and practice and SCR measurement.

RESULTS

Of 6,593 subjects who met the study criteria for single drug therapy, SCR was measured in 1,233 subjects within 30 days and in 3,896 subjects within 365 days. For combined drug therapy recipients (n = 2,497), these were 545 and 1,687, respectively. Associated cumulative probabilities were 19 % and 66 % with single drug therapy, and 22 % and 74 % with combined drug therapy. Significant differences were observed between practices. SCR measurement was associated with other characteristics, except for sex. Within 365 days, SCR increased >30 % of baseline in 103 subjects (1.6 %) after the start of single drug therapy, and in 85 (3.4 %) subjects who initiated combined drug therapy. In the majority (>70 %) of these subjects, this did not result in subsequent monitoring or adjustment of antihypertensive treatment.

CONCLUSIONS

Results from this study suggest that, on average, renal function is not monitored as strictly as recommended by relevant clinical practice guidelines.

Young age, male sex, and end-stage renal disease with secondary hyperparathyroidism as risk factors for intraoperative hyperkalemia during parathyroidectomy

STUDY OBJECTIVE

The aim of this study was to investigate the risk factors of intraoperative hyperkalemia in end-stage renal disease patients undergoing parathyroidectomy (PTx) with autotransplantation (AT).

DESIGN

Prospective observational study.

SETTING

Operating room of a tertiary care medical center.

PATIENTS

Thirty-two adult, American Society of Anesthesiologists physical status 2 and 3 patients with secondary hyperparathyroidism aged between 31 and 72 years scheduled for PTx with AT.

MEASUREMENTS

Laboratory chemistries (intact parathyroid hormone, Na, K, Ca, P, arterial blood gas) were obtained before surgery and at 2 time points during surgery. The first chemistry levels during surgery were checked after the first 2 parathyroid glands had been removed, and the second levels were checked after wound closure. Statistical analysis was performed using t test, Fisher exact test, the receiver operating characteristic curve method, as appropriate.

MAIN RESULTS

Eight patients (25%) developed hyperkalemia during surgery. The hyperkalemia patients had younger age (42±11.44 years vs 52.58±11.83 years, P=.044) and a male dominance (odds ratio, 11.4; P=.01; 95% confidence interval, 1.74-74.65). The cutoff for age was 40.5 years, according to the highest value for sensitivity plus specificity of the receiver operating characteristic curve. There was a higher incidence of intraoperative hyperkalemia in younger patients than in older patients (odds ratio, 8.33; P=.023; 95% confidence interval, 1.39-49.87) as well as a significant increase in potassium level during surgery in younger male patients (P=.005 and .002, respectively).

CONCLUSIONS

The anesthesiologist should be aware of the complications of intraoperative hyperkalemia during PTx with AT, especially in male end-stage renal disease patients younger than 40 years.

Prediction and management of hyperkalemia across the spectrum of chronic kidney disease

Hyperkalemia commonly limits optimizing treatment to slow stage 3 or higher chronic kidney disease (CKD) progression. The risk of hyperkalemia is linked to dietary potassium intake, level of kidney function, concomitant diseases that may affect potassium balance such as diabetes, and use of medications that influence potassium excretion. The risk predictors for developing hyperkalemia are an estimated glomerular filtration rate of less than 45 mL/min/1.73 m(2) and a serum potassium level greater than 4.5 mEq/L in the absence of blockers of the renin-angiotensin-aldosterone system (RAAS). Generally, monotherapy with RAAS blockers does not increase risk substantially unless hypotension or volume depletion occur. Dual RAAS blockade involving any combination of an angiotensin-converting enzyme inhibitor, angiotensin-receptor blocker, renin inhibition, or aldosterone-receptor blocker markedly increases the risk of hyperkalemia in patients with stage 3 or higher CKD. Moreover, dual RAAS blockade further reduces albuminuria by 25% to 30% compared with monotherapy, it has failed to show a benefit on CKD progression or cardiovascular outcome, and thus is not indicated in such patients because of its marked increase in hyperkalemia potential. Although sodium polystyrene resins exist to manage hyperkalemia in patients requiring therapy that increases serum potassium levels, they are not well tolerated. Newer, more predictable, better-tolerated polymers to bind potassium are on the horizon and may be approved within the next 1 to 2 years.

Development and application of indicators for the reduction of potentially preventable hospital admissions related to medications

OBJECTIVE

The Dutch HARM-Wrestling (HW) Task Force issued general and drug-specific recommendations aimed at reducing hospital admissions related to medication (HARMs). This study examines if the drug-specific recommendations could be converted into indicators that could be monitored in existing databases of general practitioner (GP) or community pharmacy (CP) data. The study also assesses the performance of these indicators before and during the official release of HW recommendations.

METHODS

HW recommendations were divided into sub-recommendations. We studied to what extent these were measurable as indicators based on available information in both databases. For each measurable indicator, performance between 2007 and 2010 was determined and possibilities for further improvement were estimated.

RESULTS

Thirty-four drug-specific HW recommendations were divided into 69 sub-recommendations, 32 of which were measurable as indicator in at least one of the databases. Application of these indicators between 2007 and 2010 showed that many of the indicators did not change over time. Possibilities for further improvement were estimated as moderate to major for 16/31 (52%) indicators measured in the GP database and 6/15 (40%) HW indicators measured in the CP database.

CONCLUSIONS

Further implementation of the HW recommendations and development of additional monitoring methods are warranted to improve drug safety in outpatients.

Monitoring and adverse events in relation to ACE inhibitor/angiotensin receptor blocker initiation in people with diabetes in general practice: a population database study

BACKGROUND AND AIM

To determine whether angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) initiation in people with diabetes is monitored as recommended by recent guidelines and the incidence of associated adverse renal events.

DESIGN

Retrospective population database analysis of 4056 people in Tayside, Scotland with type 2 diabetes prescribed an ACEI/ARB between 1 January 2005 and 31 December 2009.

METHOD

Measurement of urea and electrolytes (U&Es) before and after ACEI/ARB initiation and renal adverse events; defined as a ≥30% rise in serum creatinine and post-initiation potassium of ≥5.6 mmol/L. Associations of adverse events with patient demographics or co-prescription of drugs with known renal effects were examined.

RESULTS

Overall, 89% of initiations were with an ACE inhibitor. A total of 18.84% (CI 95% 18.82-18.86) of patients initiating ACE inhibitor or ARB had U&Es measured in the 90 days before initiation and within 5-14 days after initiation. Only 1.7% of patients had an adverse renal event. Patients prescribed with an ARB were less likely to be monitored than those prescribed with an ACE inhibitor, but no less likely to suffer harm.

CONCLUSIONS

Current clinical practice of biochemical monitoring of ACE inhibitor/ARB is poor, but adverse events are rare. Further studies with serial U&Es are needed to establish the critical time window for adverse renal events and evaluate whether intensive biochemical monitoring recommended is required in low-risk groups.

Drug Adverse Event Detection in Health Plan Data Using the Gamma Poisson Shrinker and Comparison to the Tree-based Scan Statistic

Background: Drug adverse event (AE) signal detection using the Gamma Poisson Shrinker (GPS) is commonly applied in spontaneous reporting. AE signal detection using large observational health plan databases can expand medication safety surveillance. Methods: Using data from nine health plans, we conducted a pilot study to evaluate the implementation and findings of the GPS approach for two antifungal drugs, terbinafine and itraconazole, and two diabetes drugs, pioglitazone and rosiglitazone. We evaluated 1676 diagnosis codes grouped into 183 different clinical concepts and four levels of granularity. Several signaling thresholds were assessed. GPS results were compared to findings from a companion study using the identical analytic dataset but an alternative statistical method—the tree-based scan statistic (TreeScan). Results: We identified 71 statistical signals across two signaling thresholds and two methods, including closely-related signals of overlapping diagnosis definitions. Initial review found that most signals represented known adverse drug reactions or confounding. About 31% of signals met the highest signaling threshold. Conclusions: The GPS method was successfully applied to observational health plan data in a distributed data environment as a drug safety data mining method. There was substantial concordance between the GPS and TreeScan approaches. Key method implementation decisions relate to defining exposures and outcomes and informed choice of signaling thresholds.

Preventable drug-related morbidity in community pharmacy: commentary on the implications for practice and policy of a novel intervention

This commentary relates to a paper on the development and piloting of a risk management intervention in Portuguese community pharmacy, based on validated preventable drug-related morbidity indicators. In the paper we presented the research programme and implications for future evaluation. However, we believe that the intervention may be seen as important for patient safety without further evaluation. Therefore in this commentary we discuss considerations for service roll-out, by revisiting some issues already presented and by introducing aspects such as service definition and remuneration. We argue that in the absence of service remuneration, redesign of care processes through IT support and inter-professional collaboration, and coaching to encourage the aforementioned efforts it is unlikely that the proposed risk management intervention will succeed in preventing drug-related morbidity.

Electronic health record-based monitoring of primary care patients at risk of medication-related toxicity

BACKGROUND

Timely laboratory monitoring may reduce the potential harm associated with chronic medication use. A study was conducted to determine the proportion of patients receiving National Committee for Quality Assurance (NCQA)-recommended laboratory medication monitoring in a primary care setting and to assess the effect of electronic health record (EHR)-derived, paper-based, provider-specific feedback bulletins on subsequent patient receipt of medication monitoring.

METHODS

In a single-arm, pre-post intervention in two federally qualified community health centers in Baltimore, patients targeted were adults prescribed at least 6 months (in the preceding year) for at least one index medication (digoxin, statins, diuretics, angiotensin-converting enzyme inhibitors/ angiotensin II-receptor blockers) in a 12-month period (August 2008-July 2009).

RESULTS

Among the 2,013 patients for whom medication monitoring was recommended, 42% were overdue for monitoring at some point during the study. As the number of index medications the patient was prescribed increased, the likelihood of ever being overdue for monitoring decreased. Being listed on the provider-specific monitoring bulletin doubled the odds of a patient receiving recommended laboratory monitoring before the next measurement period (1-2 months). Limiting the intervention to the most overdue patients, however, mitigated its overall impact.

CONCLUSIONS

Recommended laboratory monitoring of chronic medications appears to be inconsistent in primary care, resulting in potential harm for individuals at risk for medication-related toxicity. EHRs may be an important component of systems designed to improve medication monitoring, but multimodal interventions will likely be needed to achieve high reliability.

Laboratory monitoring of patients treated with antihypertensive drugs and newly exposed to non steroidal anti-inflammatory drugs: a cohort study

Background

Drug-Drug Interactions between Non Steroidal Anti-Inflammatory Drugs (NSAIDs) and Angiotensin Converting Enzyme Inhibitors (ACEIs), Angiotensin Receptor Blocker (ARBs) or diuretics can lead to renal failure and hyperkalemia. Thus, monitoring of serum creatinine and potassium is recommended when a first dispensing of NSAID occur in patients treated with these drugs.

Methods

We conducted a pharmacoepidemiological retrospective cohort study using data from the French Health Insurance Reimbursement Database to evaluate the proportion of serum creatinine and potassium laboratory monitoring in patients treated with ACEI, ARB or diuretic and receiving a first dispensing of NSAID. We described the first dispensing of NSAID among 3,500 patients of a 4-year cohort (6,633 patients treated with antihypertensive drugs) and analyzed serum creatinine and potassium laboratory monitoring within the 3 weeks after the first NSAID dispensing.

Results

General Practitioners were the most frequent prescribers of NSAIDs (85.5%, 95% CI: 84.3–86.6). The more commonly prescribed NSAIDs were ibuprofen (20%), ketoprofen (15%), diclofenac (15%) and piroxicam (12%). Serum creatinine and potassium monitoring was 10.7% (95% CI: 9.5–11.8) in patients treated by ACEIs, ARBs or diuretics. Overall, monitoring was more frequently performed to women aged over 60, treated with digoxin or glucose lowering drugs, but not to patients treated with ACEIs, ARBs or diuretics. Monitoring was more frequent when NSAIDs' prescribers were cardiologists or anesthesiologists.

Conclusion

Monitoring of serum creatinine and potassium of patients treated with ACEIs, ARBs or diuretics and receiving a first NSAID dispensing is insufficiently performed and needs to be reinforced through specific interventions.

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.

Adherence to biochemical monitoring recommendations in patients starting with renin angiotensin system inhibitors: a retrospective cohort study in the Netherlands

BACKGROUND

Renin angiotensin system inhibitors (RASIs) are frequently involved in serious adverse events. These events principally occur in high-risk patients and often arise within the first days after treatment initiation; therefore, guidelines recommend biochemical monitoring within 3 weeks after the start of therapy with RASIs.

OBJECTIVE

The purpose of this study was to examine the level of biochemical monitoring directly after treatment initiation with RASIs in patients with different risk profiles and to study the attitudes of the physicians involved towards biochemical monitoring.

METHODS

We carried out a retrospective analysis of 202 patients who started RASI therapy in 2006 in Groesbeek, the Netherlands. We determined the rate of serum creatinine and potassium monitoring within 3 weeks after the start of therapy. In addition, we studied the intentions and attitudes towards biochemical monitoring during RASI therapy among 68 general practitioners and medical specialists by way of a brief questionnaire.

RESULTS

Serum creatinine and potassium monitoring after treatment initiation was performed in 34% and 28% of patients, respectively. Of all the patients, 29% had two or more additional risk factors for renal function deterioration. In these high-risk patients, creatinine was significantly less often monitored compared with low-risk patients (22% vs 39%). In contrast to these findings, the prescribing physicians claimed to check serum creatinine within 2 weeks after treatment initiation in 85% of their patients. Most of the prescribing physicians (88%) rated this monitoring as (very) important.

CONCLUSIONS

We demonstrated that, despite positive intentions of physicians, the biochemical monitoring recommendation in patients treated with RASIs is poorly met. In addition, serum creatinine monitoring was significantly less often performed in high-risk patients compared with low-risk patients.

Beyond the prescription: medication monitoring and adverse drug events in older adults

Whether a person will suffer harm from a medication or how severe that harm will be is difficult to predict precisely. As a result, many adverse drug events (ADEs) occur in patients in whom it was reasonable to believe that the drug's benefits exceeded its risks. Improving safety and reducing the burden of ADEs in older adults requires addressing this uncertainty by not only focusing on the appropriateness of the initial prescribing decision, but also by detecting and mitigating adverse events once they have started to occur. Such enhanced monitoring of signs, symptoms, and laboratory parameters can determine whether an adverse event has only mild and short-term consequences or major long-term effects on morbidity and mortality. Although current medication monitoring practices are often suboptimal, several strategies can be leveraged to improve the quality and outcomes of monitoring. These strategies include using health information technology to link pharmacy and laboratory data, prospective delineation of risk, and patient outreach and activation, all within a framework of team-based approaches to patient management. Although many of these strategies are theoretically possible now, they are poorly used and will be difficult to implement without a significant restructuring of medical practice. An enhanced focus on medication monitoring will also require a new conceptual framework to re-engineer the prescribing process. With this approach, prescribing quality does not hinge on static attributes of the initial prescribing decision but entails a dynamic process in which the benefits and harms of drugs are actively monitored, managed, and reassessed over time.

An economic evaluation of a laboratory monitoring program for renin-angiotensin system agents

BACKGROUND

The efficiency of patient safety interventions is not well studied, especially laboratory monitoring for drug therapy. More than one-third of preventable adverse drug events are associated with inadequate monitoring. Current knowledge of decreasing adverse drug events through expanded monitoring programs is lacking.

DESIGN

The authors focused on a laboratory monitoring program (above usual practice) of renin-angiotensin system (RAS) agents to prevent adverse events of hyperkalemia and acute renal failure. They used a probabilistic decision model to estimate cost savings and cost effectiveness (at $30,000 and $10,000 per quality-adjusted life-year (QALY)). Costs included the monitoring program, and offsets from reduced care in 3 populations (overall, chronic kidney disease [CKD], and diabetes).

MAIN RESULTS

Adverse events were most common in those with CKD. Intervening on all new users or the subset with diabetes was almost never expected to be cost saving (probability <1%). But a monitoring program restricted to patients with CKD was expected to be cost saving (probability = 95%). A strategy that intervened on all patients, or those with diabetes, was never cost effective, (probability <1%). But intervening on patients with CKD was estimated to be cost effective (at either cost-effectiveness threshold) at least 95% of the time in the base case.

CONCLUSIONS

The authors' findings illustrate that for laboratory monitoring to be cost effective, the patient population must be at high enough risk of adverse events. Further inquiry into the willingness to pay for patient safety interventions is needed.

Life-threatening drug-associated hyperkalemia: a retrospective study from laboratory signals

PURPOSE

Life-threatening hyperkalemia may be induced by drugs and preventable in at-risk patients. This study was designed to describe cases of 'serious' drug-associated hyperkalemia.

METHODS

Adult subjects with a serum potassium concentration above 6.5 mmol/L detected at admission or during hospital stay in nephrology, cardiology, geriatric, emergency or intensive care units were identified by biology laboratories of hospitals and clinics located in Midi-Pyrenees (southwest France). Patients dialyzed for end-stage kidney disease were excluded. Data were collected from medical files. Hyperkalemia was defined as drug-associated if at least one drug known to increase serum potassium concentration was taken when hyperkalemia occurred (among drugs taken in outpatient care for hyperkalemia detected at admission and among drugs taken in outpatient care and continued at hospital and drugs introduced from admission for hyperkalemia detected during hospital stay).

RESULTS

Of 168 hyperkalemia cases, 102 (60.7%) were classified as drug-associated. They concerned elderly patients (mean age: 76.1 years) often having arterial hypertension and/or cardiac diseases (88.2%). Risk factors, mainly acute kidney failure, were observed in almost all cases (98.0%). Drugs predominantly involved were angiotensin-converting enzyme inhibitors (47.1%), spironolactone (41.2%), angiotensin II receptor antagonists (23.5%) and potassium supplements (23.5%). In 10% of cases, death could be attributed to hyperkalemia.

CONCLUSIONS

Laboratory databases allowed an exhaustive identification of hyperkalemia cases. The frequency of drug-related hyperkalemia and their characteristics suggest that treatment with drugs known to increase serum potassium concentration can be inappropriate, especially regarding associations or indications, and is highly risky for predisposed patients.

Oversight: a retrospective study of biochemical monitoring in patients beginning antihypertensive drug treatment in primary care

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Guidelines recommend biochemical monitoring of patients treated with antihypertensive agents, although there is little primary evidence for these recommendations.

WHAT THIS STUDY ADDS

Patients treated for hypertension in general practice often have no biochemical tests before, or in the 6 months after, starting drug treatment.

AIMS

Guidelines on the management of hypertension have recommended baseline testing of serum electrolyte and creatinine concentrations before treatment since the 1990s. We wished to examine the extent of laboratory monitoring in patients with newly diagnosed hypertension and newly treated with antihypertensive drugs.

METHODS

We carried out a retrospective analysis of 74,096 patients in the General Practice Research Database (GPRD) aged 18 years and older with newly diagnosed hypertension and prescribed a single antihypertensive agent. We determined the number of patients with a laboratory test for serum electrolyte and creatinine (or urea) concentrations prior to the first antihypertensive drug prescription and in the 6 months after and patient factors associated with subsequent monitoring.

RESULTS

Thirty-four thousand nine hundred and forty-seven patients (47%) had at least one biochemical test in the 12 months prior to beginning antihypertensive treatment, and 26,946 (36%) had at least one biochemical monitoring test in the 6 months after beginning antihypertensive treatment. Thirteen thousand five hundred and four (18%) had both baseline and monitoring tests. Baseline tests were normal in 11,671 patients (86%), of whom 10,213 (88%) had normal tests at first monitoring. Monitoring was significantly more likely in patients treated with ACE inhibitors than thiazides (adjusted OR 1.90; 95% CI 1.80, 2.00), older patients (adjusted OR 1.23; 95% CI 1.11, 1.36) [individuals aged 80-89 years compared with <40 years], and patients with diabetes mellitus (adjusted OR 2.03; 95% CI 1.91, 2.16).

CONCLUSION

Biochemical testing at baseline and monitoring after starting treatment is often omitted in newly diagnosed hypertensive patients. When both are tested, one in eight normal results becomes abnormal.

The positive predictive value of a hyperkalemia diagnosis in automated health care data

PURPOSE

Our objectives were to determine performance of coded hyperkalemia diagnosis at identifying (1) clinically evident hyperkalemia and (2) serum potassium>6 mmol/L.

METHODS

This retrospective observational study included 8722 patients with diabetes within an integrated healthcare system who newly initiated an angiotensin converting enzyme inhibitor, angiotensin receptor blocker, or spironolactone. The primary outcome was first hyperkalemia-associated event (hospitalization, emergency department visit or death within 24 hours of coded diagnosis and/or potassium≥6 mmol/L) during the first year of therapy. Medical records were reviewed.

RESULTS

Among a random sample of 99 patients not coded as having hyperkalemia, none had hyperkalemia upon record review. Among all 64 patients identified as having hyperkalemia, all had hospitalization or emergency department visit associated with coded diagnosis or elevated potassium. Of 55 with coded diagnosis, 42 (PPV 76%) had clinically evident hyperkalemia; 32 (PPV 58%) had potassium≥6. Of 9 identified using only potassium≥6, 7 (PPV 78%) had clinically evident hyperkalemia.

CONCLUSIONS

Nearly one-fourth of patients with coded diagnosis do not have clinically evident hyperkalemia and nearly one-half do not have potassium≥6. Because both false positives and negatives occur with coded diagnoses, medical record validation of hyperkalemia-associated outcomes is necessary.

Doctors' perceptions of laboratory monitoring in office practice

BACKGROUND

Laboratory monitoring has been increasingly recognized as an important area for improving patient safety in ambulatory care. Little is known about doctors' attitudes towards laboratory monitoring and potential ways to improve it.

METHODS

Six focus groups and one individual interview with 20 primary care doctors and nine specialists from three Massachusetts communities.

RESULTS

Participants viewed laboratory monitoring as a critical, time-consuming task integral to their practice of medicine. Most believed they commit few laboratory monitoring errors and were surprised at the error rates reported in the literature. They listed various barriers to monitoring, including not knowing which doctor was responsible for ensuring the completion of laboratory monitoring, uncertainty regarding the necessity of monitoring, lack of alerts/reminders and patient non-adherence with recommended monitoring. The primary facilitator of monitoring was ordering laboratory tests while the patient is in the office. Primary care doctors felt more strongly than specialists that computerized alerts could improve laboratory monitoring. Participants wanted to individualize alerts for their practices and warned that alerts must not interrupt work flow or require too many clicks.

CONCLUSIONS

Doctors in community practice recognized the potential of computerized alerts to enhance their monitoring protocols for some medications. They viewed patient non-adherence as a barrier to optimal monitoring. Interventions to improve laboratory monitoring should address doctor workflow issues, in addition to patients' awareness of the importance of fulfilling recommended therapeutic monitoring to prevent adverse drug events.

Managing medications in clinically complex elders: "There's got to be a happy medium"

Multiple medication use is common in older adults and may ameliorate symptoms, improve and extend quality of life, and occasionally cure disease. Unfortunately, multiple medication use is also a major risk factor for prescribing and adherence problems, adverse drug events, and other adverse health outcomes. Using the case of an older patient taking multiple medications, this article summarizes the evidence-based literature about improving medication use and withdrawing specific drugs and drug classes. It also describes a systematic approach for how health professionals can assess and improve medication regimens to benefit patients and their caregivers and families.