The safety of warfarin therapy in the nursing home setting

Safety Issues of Herb-Warfarin Interactions

Warfarin is a popular anticoagulant with high global demand. However, studies have underlined serious safety issues when warfarin is consumed concomitantly with herbs or its formulations. This review aimed to highlight the mechanisms behind herb-warfarin interactions while laying special emphasis on its PKPD interactions and evidence on Herb-Warfarin Interaction (HWI) with regards to three different scenarios, such as when warfarin is consumed with herbs, taken as foods or prescribed as medicine, or when used in special situations. A targeted literature methodology involving different scientific databases was adopted for acquiring information on the subject of HWIs. Results of the present study revealed some of the fatal consequences of HWI, including post-operative bleeding, thrombosis, subarachnoid hemorrhage, and subdural hematomas occurring as a result of interactions between warfarin and herbs or commonly associated food products from Hypericum perforatum, Zingiber officinale, Vaccinium oxycoccos, Citrus paradisi, and Punica granatum. In terms of PK-PD parameters, herbs, such as Coptis chinensis Franch. and Phellodendron amurense Rupr., were found to compete with warfarin for binding with plasma proteins, leading to an increase in free warfarin levels in the bloodstream, resulting in its augmented antithrombic effect. Besides, HWIs were also found to decrease International Normalised Ratio (INR) levels following the consumption of Persea americana or avocado. Therefore, there is an urgent need for an up-to-date interaction database to educate patients and healthcare providers on these interactions, besides promoting the adoption of novel technologies, such as natural language processing, by healthcare professionals to guide them in making informed decisions to avoid HWIs.

Effect of a Multifaceted Clinical Pharmacist Intervention on Medication Safety After Hospitalization in Persons Prescribed High-risk Medications: A Randomized Clinical Trial

IMPORTANCE

The National Action Plan for Adverse Drug Event (ADE) Prevention identified 3 high-priority, high-risk drug classes as targets for reducing the risk of drug-related injuries: anticoagulants, diabetes agents, and opioids.

OBJECTIVE

To determine whether a multifaceted clinical pharmacist intervention improves medication safety for patients who are discharged from the hospital and prescribed medications within 1 or more of these high-risk drug classes.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial was conducted at a large multidisciplinary group practice in Massachusetts and included patients 50 years or older who were discharged from the hospital and prescribed at least 1 high-risk medication. Participants were enrolled into the trial from June 2016 through September 2018.

INTERVENTIONS

The pharmacist-directed intervention included an in-home assessment by a clinical pharmacist, evidence-based educational resources, communication with the primary care team, and telephone follow-up. Participants in the control group were provided educational materials via mail.

MAIN OUTCOMES AND MEASURES

The study assessed 2 outcomes over a 45-day posthospital discharge period: (1) adverse drug-related incidents and (2) a subset defined as clinically important medication errors, which included preventable or ameliorable ADEs and potential ADEs (ie, medication-related errors that may not yet have caused injury to a patient, but have the potential to cause future harm if not addressed). Clinically important medication errors were the primary study outcome.

RESULTS

There were 361 participants (mean [SD] age, 68.7 [9.3] years; 177 women [49.0%]; 319 White [88.4%] and 8 Black individuals [2.2%]). Of these, 180 (49.9%) were randomly assigned to the intervention group and 181 (50.1%) to the control group. Among all participants, 100 (27.7%) experienced 1 or more adverse drug-related incidents, and 65 (18%) experienced 1 or more clinically important medication errors. There were 81 adverse drug-related incidents identified in the intervention group and 72 in the control group. There were 44 clinically important medication errors in the intervention group and 45 in the control group. The intervention did not significantly alter the per-patient rate of adverse drug-related incidents (unadjusted incidence rate ratio, 1.13; 95% CI, 0.83-1.56) or clinically important medication errors (unadjusted incidence rate ratio, 0.99; 95% CI, 0.65-1.49).

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, there was not an observed lower rate of adverse drug-related incidents or clinically important medication errors during the posthospitalization period that was associated with a clinical pharmacist intervention. However, there were study recruitment challenges and lower than expected numbers of events among the study population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02781662.

Changes in Anticoagulant Utilization Among United States Nursing Home Residents With Atrial Fibrillation From 2011 to 2016

Background

Nursing home residents with atrial fibrillation are at high risk for ischemic stroke and bleeding events. The most recent national estimate (2004) indicated less than one third of this high‐risk population was anticoagulated. Whether direct‐acting oral anticoagulant (DOAC) use has disseminated into nursing homes and increased anticoagulant use is unknown.

Methods and Results

A repeated cross‐sectional design was used to estimate the point prevalence of oral anticoagulant use on July 1 and December 31 of calendar years 2011 to 2016 among Medicare fee‐for‐service beneficiaries with atrial fibrillation residing in long‐stay nursing homes. Nursing home residence was determined using Minimum Data Set 3.0 records. Medicare Part D claims for apixaban, dabigatran, edoxaban, rivaroxaban, and warfarin were identified and point prevalence was estimated by determining if the supply from the most recent dispensing covered each point prevalence date. A Cochran‐Armitage test was performed for linear trend in prevalence. On December 31, 2011, 42.3% of 33 959 residents (median age: 85; Q1 79, Q3 90) were treated with an oral anticoagulant, of whom 8.6% used DOACs. The proportion receiving treatment increased to 47.8% of 37 787 residents as of December 31, 2016 (P<0.01); 48.2% of 18 054 treated residents received DOACs. Demographic and clinical characteristics of residents using DOACs and warfarin were similar in 2016. Half of the 8734 DOAC users received standard dosages and most were treated with apixaban (54.4%) or rivaroxaban (35.8%) in 2016.

Conclusions

Increases in anticoagulant use among US nursing home residents with atrial fibrillation coincided with declining warfarin use and increasing DOAC use.

Healthcare resource utilization and costs among nonvalvular atrial fibrillation patients initiating rivaroxaban or warfarin in skilled nursing facilities: a retrospective cohort study

Objective: Atrial fibrillation (AF) is present in up to 17% of patients in skilled nursing facilities (SNFs). This study compared healthcare resource utilization (HRU) and costs between AF patients initiating rivaroxaban or warfarin in SNFs.Methods: Using de-identified claims from Optum Clinformatics Extended Data Mart (1 January 2013 to 31 December 2017), this retrospective cohort study indexed AF patients with first SNF admission during which rivaroxaban or warfarin was initiated within 3 days of admission. To adjust for selection bias, inverse probability of treatment weighting (IPTW) was applied for baseline characteristics. Logistic regression and generalized linear models were used to compare HRU and costs.Results: 519 rivaroxaban and 1129 warfarin patients met inclusion criteria. After IPTW, the cohorts were well balanced for baseline characteristics. The average length of index SNF stay was 32.07 and 37.44 days for rivaroxaban and warfarin patients, respectively. During SNF stay, rivaroxaban patients had 27% lower odds of hospitalization (p < .0001), 2.7 fewer international normalized ratio (INR) tests per-patient-per-month (PPPM; p < .001), and 2.3 fewer pathology/laboratory encounters PPPM (p < .0001) than warfarin patients. All-cause healthcare costs were $2638 lower with rivaroxaban versus warfarin (p < .0001) during the index SNF stay, with lower medical costs (p < .0001) but higher pharmacy costs (p < .0001). Total all-cause healthcare costs 100 days post-index SNF were $8746 lower with rivaroxaban versus warfarin (p < .0001).Conclusions: In the SNF setting, AF patients treated with rivaroxaban had 5-day shorter length of stay, lower HRU, and lower all-cause total and medical costs compared to warfarin, despite higher treatment costs. These findings may help inform clinical decision-making to reduce economic burden.

[Treatment with oral anticoagulants in older patients: Should warfarin still be prescribed?]

Vitamin-K antagonists (VKA) have been the standard for oral anticoagulation. However, they carry several problems in older patients: frequent bleeding complications, complex management, risk of interactions with multiple drugs. Two classes of direct oral anticoagulants (DOA) are currently available in France: (a) direct thrombin inhibitors: dabigatran; and (b) direct factor Xa inhibitors: rivaroxaban, apixaban and others. Their management is easier: quickly effective after administration, they are given at fixed doses and do not need regular laboratory monitoring. Several randomized trials have shown that DOA are non-inferior to VKA for treating venous thromboembolic disease (prophylactic or curative treatment) and atrial fibrillation (prevention of associated embolisms). DOA might be also effective for long-term treatment of coronary disease, in some cases. No trial has specifically studied older patients. In the context of atrial fibrillation, subgroup analysis show similar results between patients above and below 75-years-old. Lower doses of dabigatran and apixaban should be used in many older people. All DOA are eliminated at least partly by kidneys. Their dose must be reduced in moderate renal failure (filtration glomerular rate (FGR) 30 to 50mL/min) and they are contraindicated in older patients with severe renal failure (FGR<30mL/min). DOA also have other problems: (a) important drug interactions are still possible, (b) the clinical application of specific coagulation tests need to be defined, (c) their safety in some subgroups of elderly patients, very different from patients included in clinical trials, is not known.

Anticoagulant medication errors in hospitals and primary care: a cross-sectional study

Objective

To assess the proportion of all medication error reports in hospitals and primary care that involved an anticoagulant. Secondary objectives were the anticoagulant involved, phase of the medication process in which the error occurred, causes and consequences of 1000 anticoagulant medication errors. Additional secondary objectives were the total number of anticoagulant medication error reports per month, divided by the total number of medication error reports per month and the proportion of causes of 1000 anticoagulant medication errors (comparing the pre- and post-guideline phase).

Design

A cross-sectional study.

Setting

Medication errors reported to the Central Medication incidents Registration reporting system.

Participants

Between December 2012 and May 2015, 42 962 medication errors were reported to the CMR.

Intervention

N/A.

Main outcome measure

Proportion of all medication error reports that involved an anticoagulant. Phase of the medication process in which the error occurred, causes and consequences of 1000 anticoagulant medication errors. The total number of anticoagulant medication error reports per month, divided by the total number of medication error reports per month (comparing the pre- and post-guideline phase) and the total number of causes of 1000 anticoagulant medication errors before and after introduction of the LSKA 2.0 guideline.

Results

Anticoagulants were involved in 8.3% of the medication error reports. A random selection of 1000 anticoagulant medication error reports revealed that low-molecular weight heparins were most often involved in the error reports (56.2%). Most reports concerned the prescribing phase of the medication process (37.1%) and human factors were the leading cause of medication errors mentioned in the reports (53.4%). Publication of the national guideline on integrated antithrombotic care had no effect on the proportion of anticoagulant medication error reports. Human factors were the leading cause of medication errors before and after publication of the guideline.

Conclusions

Anticoagulant medication errors occurred in 8.3% of all medication errors. Most error reports concerned the prescribing phase of the medication process. Leading cause was human factors. The publication of the guideline had no effect on the proportion of anticoagulant medication errors.

Preventability of serious thromboembolic and bleeding events related to the use of oral anticoagulants: a prospective study

AIMS

To determine the preventability of serious adverse drug reactions (ADRs) related to the use of direct oral anticoagulants (DOACs), and to explore contributing factors to preventable ADRs. Results were compared with vitamin K antagonists (VKAs).

METHODS

We conducted a prospective observational study in the emergency departments of two teaching hospitals from July 2015 to January 2016. Patients admitted with a thrombotic or bleeding event while under DOAC or VKA were included. Four independent reviewers assessed causality, seriousness and preventability of ADRs using pilot-tested scales. For cases of serious and potentially preventable ADRs, we performed semi-structured interviews with general practitioners to identify contributing factors to ADRs. The primary outcome was the proportion of serious ADRs that were potentially preventable.

RESULTS

The analysis included 46 DOAC and 43 VKA patients (median age 79 years). Gastrointestinal (n = 34) and intracranial (n = 16) bleedings were the most frequent ADRs. Results were that 53% of DOAC- and 61% of VKA-related serious ADRs were deemed potentially preventable. Prescribing issues and inadequate monitoring were frequent for DOAC and VKA respectively. We identified many causes of preventable ADRs that applied to all oral anticoagulants, such as pharmacodynamic drug interactions and lack of communication.

CONCLUSIONS

More than half of serious ADRs were potentially preventable for both DOACs and VKAs. Interventions focusing on prescribing, patient education and continuity of care should help improve the use of DOACs in practice.

Role of Antiplatelet Therapy in Stroke Prevention in Patients With Atrial Fibrillation

Patients with atrial fibrillation are at increased risk of having a cardioembolic stroke. The use of oral anticoagulation is now well established to prevent strokes in patients with atrial fibrillation and a CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years [2 points], diabetes mellitus, prior stroke/transient ischemic attack or thromboembolism [2 points], vascular disease, age 65 to 74 years, and sex category) score of greater than 1, beyond sex. However, the role of antiplatelet therapy, specifically aspirin in low-risk patients or as an alternative to oral anticoagulation, remains controversial. The most recent US guidelines conflict with the European guidelines, which do not recommend antiplatelet monotherapy for stroke prevention irrespective of stroke risk. The aim of this review is to summarize published studies that question the role of aspirin in preventing strokes associated with atrial fibrillation. Overall, aspirin is found to play a limited role in the prevention of stroke in patients with atrial fibrillation and is associated with a similar risk of hemorrhagic events compared with anticoagulants. The benefit of dual antiplatelet therapy as an alternative to oral anticoagulation requires further study.

Validation of knowledge and adherence assessment tools among patients on warfarin therapy in a Saudi hospital anticoagulant clinic

Background Although it can result in serious complications due to its narrow therapeutic index, warfarin is widely used in the treatment and prevention of thromboembolic disorders. However, patients' adherence and knowledge are determinants of therapeutic success. Objective We sought to validate instruments to provide a reliable means of identifying gaps in patient understanding and nonadherence to inform targeted pharmacists' interventions to improve these measures. Methods A cross-sectional survey was conducted. Patients' knowledge about warfarin was rated using an Arabic-language tool. Medication adherence was assessed using the eight-item Morisky Medication Adherence Scale (MMAS-8). The international normalized ratio (INR) control was quantified by the Rosendaal Method. Setting At the Security Forces hospital anticoagulant clinic (ACC), Riyadh. Main outcome measure Validity of a Knowledge and adherence tool. Results Totally, 101 patients completed the questionnaires. Interestingly, the knowledge tool demonstrated good internal consistency (total Cronbach's alpha = 0.75) and significant concurrent validity with adherence levels. Fifty-two patients were classified as having unsatisfactory knowledge. Deficiency in knowledge was most obvious with respect to the consequences of missing a dose and when to seek immediate medical attention. The MMAS-8 had moderate reliability (Cronbach's alpha = 0.65); however, its concurrent validity with good INR control was not demonstrated. Conclusions This study revealed high prevalence of nonadherence and poor knowledge in the population visiting the ACC. Given that available knowledge and adherence tools seemed to have little validity in predicting clinical outcomes, structured tools should be designed, considering progression in clinical outcomes with future pharmacists' interventions.

Assessment of Oral Anticoagulant Use in Residents of Long-Term Care Homes: Evidence for Contemporary Suboptimal Use

Objective: To describe the quality of warfarin use in residents of long-term care facilities and investigate potential predictors oral anticoagulant use. Design: Retrospective chart review (August 2013 to September 2014). Setting: Thirteen long-term care (LTC) and assisted living facilities (ALF). Participants: Residents from LTC or ALF settings who ( a) received warfarin or direct-acting oral anticoagulants (DOACs) and ( b) residents with a valid indication for oral anticoagulants such as atrial fibrillation, venous thromboembolism, but were not receiving these drugs. Primary Outcome: Time in therapeutic international normalized ratio (INR) range (TTR). Results: A total of 563 residents (70% female) with an average age of 85 years were identified. Participants had an average of 7.5 comorbidities and 9 medications. A total of 391 (69%) residents with indications for OACs were receiving such medications. Indications were atrial fibrillation (63%), venous or pulmonary embolism (16%), cardiac valves (0.4%); 26% did not have documented indications. Warfarin and DOACs were prescribed for 213 (38%) and 178 (32%) respectively, and 172 (31%) received no OACs The TTR ranged from 56%-75% (mean 63%). The frequency of INR determinations ranged from every 7 to 20 days, (mean 13 days) with no apparent relationship between frequency of testing and TTR. Conclusion: The TTR was higher (63.8%) than literature average (50%), but remains suboptimal given expected benefits of TTRs >75% versus TTRs circa 60%. Documentation of indications for OACs needs improvement, and it is possible that OACs are underused. Further work is necessary to understand how OAC use may be optimized in these facilities.

The effect of nurse-led care on stability time in therapeutic range of INR in ischemic stroke patients receiving warfarin

PURPOSE

The current study is designed in order to investigate the effect of nurse-led care (the supportive and educational measurements by nurses) on stability time in therapeutic range of INR in ischemic stroke patients receiving Warfarin.

METHOD

In this quasi-experimental study, 80 ischemic stroke patients were investigated, 40 patients in experimental group and 40 in the control group referred to the nurse-based warfarin clinics affiliated to Shiraz University of Medical Sciences. The mean±SD duration of the intervention was 144±84days. The patients based on the percentage stability time in the therapeutic range of INR were classified into 3 groups of good control (>75%), medium control (60-75%), and poor control groups (<60%). The results were analyzed using qui-square and independent t-test according to these categories.

RESULTS

38 patients in the experimental group and 39 in the control group had the therapeutic range of INR 2-3. The percentage of the stability time in the therapeutic range of INR (mean±SD) in the experimental group was 64.08%±18.7 and in the control group it was 44.58%±25.12 (P<0.001). The percentage of total INRs within the therapeutic range was 52.5% in the experimental group and 40.6% in the control group (P=0.001).

CONCLUSIONS

In conclusion, using the stroke prevention guidelines, thrombotic therapy protocols and familiarity with patients' diagnosis and risk factors in the experimental group led to more patients' stability time (The time that patients could remain stable within the INR therapeutic range) in their therapeutic range of INR as the best indicator of clinical performance.

Measuring Harm in Health Care: Optimizing Adverse Event Review

OBJECTIVE

The objective of this study was to identify modifiable factors that improve the reliability of ratings of severity of health care-associated harm in clinical practice improvement and research.

METHODS

A diverse group of clinicians rated 8 types of adverse events: blood product, device or medical/surgical supply, fall, health care-associated infection, medication, perinatal, pressure ulcer, surgery. We used a generalizability theory framework to estimate the impact of number of raters, rater experience, and rater provider type on reliability.

RESULTS

Pharmacists were slightly more precise and consistent in their ratings than either physicians or nurses. For example, to achieve high reliability of 0.83, 3 physicians could be replaced by 2 pharmacists without loss in precision of measurement. If only 1 rater was available for rating, ∼5% of the reviews for severe harm would have been incorrectly categorized. Reliability was greatly improved with 2 reviewers.

CONCLUSIONS

We identified factors that influence the reliability of clinician reviews of health care-associated harm. Our novel use of generalizability analyses improved our understanding of how differences affect reliability. This approach was useful in optimizing resource utilization when selecting raters to assess harm and may have similar applications in other settings in health care.

Underlying risk factors for prescribing errors in long-term aged care: a qualitative study

OBJECTIVES

To identify system-related risk factors perceived to contribute to prescribing errors in Australian long-term care settings, that is, residential aged care facilities (RACFs).

DESIGN AND SETTING

The study used qualitative methods to explore factors that contribute to unsafe prescribing in RACFs. Data were collected at three RACFs in metropolitan Sydney, Australia between May and November 2011. Participants included RACF managers, doctors, pharmacists and RACF staff actively involved in prescribing-related processes. Methods included non-participant observations (74 h), in-depth semistructured interviews (n=25) and artefact analysis. Detailed process activity models were developed for observed prescribing episodes supplemented by triangulated analysis using content analysis methods.

RESULTS

System-related factors perceived to increase the risk of prescribing errors in RACFs were classified into three overarching themes: communication systems, team coordination and staff management. Factors associated with communication systems included limited point-of-care access to information, inadequate handovers, information storage across different media (paper, electronic and memory), poor legibility of charts, information double handling, multiple faxing of medication charts and reliance on manual chart reviews. Team factors included lack of established lines of responsibility, inadequate team communication and limited participation of doctors in multidisciplinary initiatives like medication advisory committee meetings. Factors related to staff management and workload included doctors' time constraints and their accessibility, lack of trained RACF staff and high RACF staff turnover.

CONCLUSIONS

The study highlights several system-related factors including laborious methods for exchanging medication information, which often act together to contribute to prescribing errors. Multiple interventions (eg, technology systems, team communication protocols) are required to support the collaborative nature of RACF prescribing.

Developing a list of high-alert medications for patients with chronic diseases

BACKGROUND

Patients with chronic diseases often receive multiple medications and are associated with increased vulnerability to medication errors. Identifying high-alert medications for them would help to prioritize the interventions with greatest impact for improving medication safety. The aim of this study was to develop a list of high-alert medications for patients with chronic illnesses (HAMC list) that would prove useful to the Spanish National Health Service strategies on chronicity.

METHODS

The RAND/UCLA appropriateness method was used. Drug classes/drugs candidates to be included on the HAMC list were identified from a literature search in MedLine, bulletins issued by patient safety organizations, incidents recorded in Spanish incident reporting systems, and previous lists. Eighteen experts in patient/medication safety or in chronic diseases scored candidate drugs for appropriateness according to three criteria (evidence, benefit and feasibility of implementing safety practices). Additionally they rated their priority of inclusion on a Likert scale.

RESULTS

The final HAMC list includes 14 drug classes (oral anticoagulants, narrow therapeutic range antiepileptics, antiplatelets - including aspirin -, antipsychotics, β-blockers, benzodiazepines and analogues, corticosteroids long-term use, oral cytostatics, oral hypoglycemic drugs, immunosuppressants, insulins, loop diuretics, nonsteroidal anti-inflammatory drugs, and opioid analgesics), and 4 drugs or pairs of drugs (amiodarone/ dronedarone, digoxin, oral methotrexate and spironolactone/eplerenone).

CONCLUSIONS

An initial list of high-alert medications for patients with chronic diseases has been developed, which can be built into the medication management strategies for chronicity to guide the implementation of efficient safety strategies and to identify those patients at greater risk for preventable adverse drug events.

A survey of nursing home physicians to determine laboratory monitoring adverse drug event alert preferences

OBJECTIVE

We conducted a survey of nursing home physicians to learn about (1) the laboratory value thresholds that clinical event monitors should use to generate alerts about potential adverse drug events (ADEs); (2) the specific information to be included in the alerts; and (3) the communication modality that should be used for communicating them.

METHODS

Nursing home physician attendees of the 2010 Conference of AMDA: The Society for Post-Acute and Long-Term Care Medicine.

RESULTS

A total of 800 surveys were distributed; 565 completed surveys were returned and seven surveys were excluded due to inability to verify that the respondents were physicians (a 70% net valid response rate). Alerting threshold preferences were identified for eight laboratory tests. For example, the majority of respondents selected thresholds of ≥5.5 mEq/L for hyperkalemia (63%) and ≤3.5 without symptoms for hypokalemia (54%). The majority of surveyed physicians thought alerts should include the complete active medication list, current vital signs, previous value of the triggering lab, medication change in the past 30 days, and medication allergies. Most surveyed physicians felt the best way to communicate an ADE alert was by direct phone/voice communication (64%), followed by email to a mobile device (59%).

CONCLUSIONS

This survey of nursing home physicians suggests that the majority prefer alerting thresholds that would generally lead to fewer alerts than if widely accepted standardized laboratory ranges were used. It also suggests a subset of information items to include in alerts, and the physicians' preferred communication modalities. This information might improve the acceptance of clinical event monitoring systems to detect ADEs in the nursing home setting.

Anticoagulation in long-term care: how can we improve medication monitoring?

Thromboembolic diseases affect a significant proportion of older adults; however, due to the risks and associated adverse events with anticoagulation therapy, this population may be less likely to receive the best care. Among anticoagulant-related events within the nursing home, most involve oral anticoagulant agents and occur due to deficiencies in monitoring. With the recent approvals of new oral anticoagulant agents dabigatran, rivaroxaban, and apixaban, more options are now available for treating thrombotic disorders. Ensuring that all members of the health care team are aware of the risks and benefits of these agents is paramount to improving the monitoring as well as safety in older adults who are at greatest risk for adverse events.

Anticoagulant medication errors in nursing homes: characteristics, causes, outcomes, and association with patient harm

Appropriate and safe use of medications is an important aspect of quality of care in nursing home patients. Because of their complex medication use process, anticoagulants are prone to medication errors in the frail elderly. Therefore, we designed this study to characterize anticoagulant medication errors and to evaluate their association with patient harm using individual medication error incidents reported by all North Carolina nursing homes to the Medication Error Quality Initiative (MEQI) during fiscal years 2010-2011. Characteristics, causes, and specific outcomes of harmful anticoagulant medication errors were reported as frequencies and proportions and compared between anticoagulant errors and other medication errors using chi-square tests. A multivariate logistic regression model explored the relationship between anticoagulant medication errors and patient harm, controlling for patient- and error-related factors.

Prescribing in care homes: the role of the geriatrician

Large numbers of frail elderly people spend some time of their lives in care homes. Increasing age is associated with altered physiology, multiple diagnoses and complex comorbidity, and polypharmacy. Those living in care homes often take larger numbers of medications than those who live in the community and the risk of morbidity as a direct or indirect result of medications is high. Many methods have been suggested to revise the number and type of medications prescribed for individuals at risk of adverse drug reactions (ADRs), both in the community and in hospital with variable success and implementation. Assessment of prescribed and nonprescribed medications by pharmacists, nurses and general practitioners all have a role in optimizing therapeutics with evidence that improved prescribing can reduce the risk of ADRs. In conjunction with these professionals, community geriatricians undertaking a comprehensive geriatric assessment can reduce the number of medications prescribed or optimize therapy where there may be underprescribing (e.g. in depression), thereby reducing the overall risk of hospital admission ADRs.

Evaluation of a Pharmacist-Managed Anticoagulation Clinic

Background

Anticoagulation therapy is important in the prevention and treatment of cardioembolic events. Warfarin is frequently used but requires continual monitoring to ensure safety and efficacy. The target time in therapeutic range (TTR) is not always achieved.

Objectives

The objectives for this study were to determine the TTR for a pharmacist-managed anticoagulation clinic and identify reasons for sub- and supratherapeutic international normalized ratio (INR) values.

Methods

Medical records for subjects prescribed warfarin were reviewed. Demographic and relevant clinical information was assessed. INR measurements were extracted for subjects enrolled. The TTR was calculated, and the cause for sub- or supratherapeutic values was determined when possible.

Results

One hundred twenty-six subjects were included in this retrospective study. The calculated TTR was 51%. The cause for more than 65% of the sub- and supratherapeutic INR values could not be determined. One subject incurred a clot and 6 subjects suffered a bleed. No deaths occurred. Age was the only factor that correlated with a supratherapeutic INR value ( r = −0.179, P = .045).

Conclusion

Pharmacists in the anticoagulation clinic are effectively managing patients who are taking warfarin by frequently maintaining INR values near or within the recommended therapeutic range. Very few negative outcomes occurred during the time of study.

Novel anticoagulants in atrial fibrillation stroke prevention

This review article evaluates novel oral anticoagulants in comparison with warfarin for thromboembolism prophylaxis in patients with atrial fibrillation (AF). AF is the most frequently diagnosed arrhythmia in the United States. The most serious side effect of AF is stroke. Warfarin has several decades of proven efficacy in AF-related stroke prevention but the drug's numerous drawbacks make its implementation difficult for practitioners and patients. The difficulties of warfarin have prompted the development of alternative anticoagulants for AF-related stroke prevention with better efficacy, safety, and convenience. The oral direct thrombin inhibitor, dabigatran, and the oral factor Xa inhibitors, rivaroxaban and apixaban, have been evaluated in a large phase III trial. Dabigatran, rivaroxaban and apixaban were shown to be noninferior compared with warfarin in the prevention of stroke. Dabigatran and apixaban were found to be statistically superior to warfarin. All three may also have a better safety profile than warfarin. In conclusion, novel anticoagulants have a different pharmacologic profile compared with warfarin that may eliminate many of the treatment inconveniences. Practitioners must also be aware of the disadvantages these new drugs possess when choosing a management strategy for their patients. Drug selection may become clearer as these new drugs are used more extensively.

Use of warfarin in long-term care: a systematic review

BACKGROUND

The use of warfarin in older patients requires special consideration because of concerns with comorbidities, interacting medications, and the risk of bleeding. Several studies have suggested that warfarin may be underused or inconsistently prescribed in long-term care (LTC); no published systematic review has evaluated warfarin use for stroke prevention in this setting. This review was conducted to summarize the body of published original research regarding the use of warfarin in the LTC population.

METHODS

A systematic literature search of the PubMed, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library was conducted from January 1985 to August 2010 to identify studies that reported warfarin use in LTC. Studies were grouped by (1) rates of warfarin use and prescribing patterns, (2) association of resident and institutional characteristics with warfarin prescribing, (3) prescriber attitudes and concerns about warfarin use, (4) warfarin management and monitoring, and (5) warfarin-related adverse events. Summaries of study findings and quality assessments of each study were developed.

RESULTS

Twenty-two studies met the inclusion criteria for this review. Atrial fibrillation (AF) was the most common indication for warfarin use in LTC and use of warfarin for stroke survivors was common. Rates of warfarin use in AF were low in 5 studies, ranging from 17% to 57%. These usage rates were low even among residents with high stroke risk and low bleeding risk. Scored bleeding risk had no apparent association with warfarin use in AF. In physician surveys, factors associated with not prescribing warfarin included risk of falls, dementia, short life expectancy, and history of bleeding. International normalized ratio was in the target range approximately half of the time. The combined overall rate of warfarin-related adverse events and potential events was 25.5 per 100 resident months on warfarin therapy.

CONCLUSIONS

Among residents with AF, use of warfarin and maintenance of INR levels to prevent stroke appear to be suboptimal. Among prescribers, perceived challenges associated with warfarin therapy often outweigh its benefits. Further research is needed to explicitly consider the appropriate balancing of risks and benefits in this frail patient population.

[Management and therapy of atrial fibrillation in geriatric patients]

Among geriatric patients, atrial fibrillation is the most common cardiac arrhythmia. In patients over 80 years of age, the prevalence rises to approximately 10%. Atrial fibrillation is associated with serious health implications, including a 2-fold increase in mortality risk and a 5-fold increase in stroke risk. In contrast to these facts, the current guidelines on the management of atrial fibrillation of the European Society of Cardiology (ESC) contain only a short paragraph on these patients. Many relevant clinical aspects go without any comment. Thus, the purpose of our paper is to discuss those special needs of geriatric patients and their physicians which are not mentioned in the guidelines of the ESC. In our review, we discuss rhythm versus rate control, oral anticoagulation, outcome, prevention, falls, adherence, polypharmacy, dementia, nursing home patients, frailty, and geriatric assessment in consideration of geriatric patients. An extended search of the literature on Pubmed served as the basis for this review. Individual aspects of each geriatric patient should be considered when managing these complex patients; however, the complexity of each case must not lead to an individualized therapy that is not in accordance with current guidelines and the literature. A large number of papers which help us to answer most of the clinical questions regarding the management of trial fibrillation in geriatric patients have already been published.

Challenges of Older Patients’ Knowledge About Warfarin Therapy

Objective: To review the challenges of warfarin education for older patients (aged 65 years or older) in terms of knowledge, access to warfarin education, and education resources. Methods: A quasi-systematic review of the literature was performed via electronic database searches (eg, Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, International Pharmaceutical Abstracts, Meditext, and Google Scholar) from 1990 to May 2011. Results: The 62 articles reviewed found that improved patient knowledge results in better anticoagulation control. The review also found that between 50% and 80% of older patients have inadequate knowledge about the basic aspects of warfarin therapy (eg, action, benefits and risks, interactions with other drugs or foods, international normalized ratio management). Demographic factors, such as advancing age, lower family income, and limited health literacy, were found to inversely affect patients’ warfarin knowledge, and access to warfarin education and information resources were often suboptimal in different practice settings. Finally, a number of educational strategies and resources that could be readily incorporated to improve the effectiveness of current warfarin education programs were extracted from the review. Conclusion: This comprehensive review highlights that education about warfarin in older patients is currently suboptimal and may in part contribute to poor therapeutic outcomes. This review article also acknowledges the need to identify, target, and develop educational strategies and resources to further improve older patients’ knowledge about their warfarin therapy.

Evaluation of warfarin drug interaction listings in US product information for warfarin and interacting drugs

BACKGROUND

Because interactions with warfarin represent a serious risk to patients, drug information sources used by clinicians should contain accurate, timely, and practical drug interaction information.

OBJECTIVE

The aim of this study was to assess the information regarding warfarin interactions that is included in the official labeling of prescription products that interact with warfarin.

METHODS

We examined the official labeling information approved by the US Food and Drug Administration for the 50 drugs, biologics, and drug classes that were commonly identified by 3 drug information compendia--Clinical Pharmacology, ePocrates(®), and Micromedex(®)--and the warfarin US prescribing information (PI) as having an interaction with warfarin. The PI of each product was assessed for possible mention of an interaction with warfarin. The data were collected and tabulated by 1 investigator. A clinical investigator evaluated the data for accuracy and consistency. Unresolved issues were discussed with a third investigator and decided by consensus. The interaction listings were compared to determine similarities, differences, and inconsistencies and analyzed by 5 investigators.

RESULTS

Of the labeling for 73 products evaluated, 62 (85%) included mention of an interaction with warfarin. Those failing to mention the warfarin interaction were for older generic drugs or influenza vaccine. Among the labels listing an interaction with warfarin, the location of the information, the terminology used, and the inclusion of evidence for the interaction was inconsistent . When considering the PI for all 73 products, Fleiss' kappa coefficient (κ = 0.467) suggested moderate concordance according to the method of Landis and Koch.

CONCLUSION

This assessment of official US product labeling for 50 drugs, biologics, and drug classes known to interact with warfarin, comprising 73 distinct agents, found that 15% failed to mention the interaction, even though the interaction was mentioned in the warfarin labeling.

Randomized trial of a warfarin communication protocol for nursing homes: an SBAR-based approach

BACKGROUND

More than 1.6 million Americans currently reside in nursing homes. As many as 12% of them receive long-term anticoagulant therapy with warfarin. Prior research has demonstrated compelling evidence of safety problems with warfarin therapy in this setting, often associated with suboptimal communication between nursing home staff and prescribing physicians.

METHODS

We conducted a randomized trial of a warfarin management protocol using facilitated telephone communication between nurses and physicians in 26 nursing homes in Connecticut in 2007-2008. Intervention facilities received a warfarin management communication protocol using the approach "Situation, Background, Assessment, and Recommendation" (SBAR). The protocol included an SBAR template to standardize telephone communication about residents on warfarin by requiring information about the situation triggering the call, the background, the nurse's assessment, and recommendations.

RESULTS

There were 435 residents who received warfarin therapy during the study period for 55,167 resident days in the intervention homes and 53,601 in control homes. In intervention homes, residents' international normalized ratio (INR) values were in the therapeutic range a statistically significant 4.50% more time than in control homes (95% confidence interval [CI], 0.31%-8.69%). There was no difference in obtaining a follow-up INR within 3 days after an INR value ≥4.5 (odds ratio 1.02; 95% CI, 0.44-2.4). Rates of preventable adverse warfarin-related events were lower in intervention homes, although this result was not statistically significant: the incident rate ratio for any preventable adverse warfarin-related event was .87 (95% CI, .54-1.4).

CONCLUSION

Facilitated telephone communication between nurses and physicians using the SBAR approach modestly improves the quality of warfarin management for nursing home residents.

Predictors of anticoagulation in hospice patients with lung cancer

BACKGROUND

Guidelines recommend lifelong anticoagulation in patients with cancer and a history of thromboembolism, but the use of anticoagulation in hospice has not been described. A retrospective study of medication data was conducted to determine patterns of anticoagulant use and predictors of type of anticoagulant prescribed for hospice patients with lung cancer.

METHODS

Medication data were evaluated for 16,896 hospice patients with lung cancer in 2006 to determine patient and hospice characteristics that predicted anticoagulant prescription. Independent predictors of warfarin versus low molecular weight heparin (LMWH) prescription were identified using a logistic regression model.

RESULTS

One of every 11 patients was prescribed an anticoagulant, most commonly warfarin. Compared with patients prescribed LMWH, patients prescribed warfarin were older (71.6 vs 65.8 years, P<.001), were more likely white (81.2% vs 74.3%, P = .03), had a longer stay in hospice (median 21 days vs 17 days, P = .001), and were more likely to have ≥3 comorbid illnesses (37.5% vs 25.0%, P<.001). The strongest independent predictor of type of anticoagulant prescribed was geographic region, with hospices in the Northeast more likely to prescribe LMWH.

CONCLUSIONS

Anticoagulant use is prevalent in patients with lung cancer enrolled in hospice. This study highlights the need to understand the benefits and risks of anticoagulation at the end of life.

The quality of warfarin prescribing and monitoring in Veterans Affairs nursing homes

OBJECTIVES

To describe the quality of warfarin prescribing and monitoring in Veterans Affairs (VA) nursing homes and to assess the factors associated with maintaining a therapeutic international normalized ratio (INR).

DESIGN

Retrospective cohort.

SETTING

Five VA nursing homes.

PARTICIPANTS

All veterans who received warfarin between January 1 and June 30, 2008, at the nursing homes.

MEASUREMENTS

Using medical records, the percentage of person-time spent in the target INR range, the proportion of patients with INRs in the therapeutic range on 50% or more of their person-days, and the frequency of INR monitoring were estimated. Multivariable logistic regression was used to identify factors associated with maintaining a therapeutic INR 50% or more of the time.

RESULTS

Over 6 months, 160 patients received 10,380 person-days of warfarin. INRs were in the therapeutic range for 55% of the person-days, and 99% of the INR tests were repeated within 4 weeks of the previous result. On an individual level, 49% of patients had INRs in the target range for 50% or more of their person-days. Achieving this outcome was more likely in patients with prevalent warfarin use than with new use (adjusted odds ratio (AOR)=2.86, 95% confidence interval (CI)=1.06-7.72). Conversely, patients with a history of a stroke (AOR=0.38, 95% CI =0.18-0.80) were less likely to have therapeutic INRs for 50% or more of their days.

CONCLUSION

Warfarin appears to be prescribed and monitored effectively in VA nursing home patients. Future studies should focus on increasing time in therapeutic range in patients with poor INR control.

A team-based approach to warfarin management in long term care: a feasibility study of the MEDeINR electronic decision support system

Background

Previous studies in long-term care (LTC) have demonstrated that warfarin management is suboptimal with preventable adverse events often occurring as a result of poor International Normalized Ratio (INR) control. To assist LTC teams with the challenge of maintaining residents on warfarin in the therapeutic range (INR of 2.0 to 3.0), we developed an electronic decision support system that was based on a validated algorithm for warfarin dosing. We evaluated the MEDeINR system in a pre-post implementation design by examining the impact on INR control, testing frequency, and experiences of staff in using the system.

Methods

For this feasibility study, we piloted the MEDeINR system in six LTC homes in Ontario, Canada. All128 residents (without a prosthetic valve) who were taking warfarin were included. Three-months of INR data prior to MEDeINR was collected via a retrospective chart audit, and three-months of INR data after implementation of MEDeINR was captured in the central computer database. The primary outcomes compared in a pre-post design were time in therapeutic range (TTR) and time in sub/supratherapeutic ranges based on all INR measures for every resident on warfarin. Secondary measures included the number of monthly INR tests/resident and survey/focus-group feedback from the LTC teams.

Results

LTC homes in our study had TTR's that were higher than past reports prior to the intervention. Overall, the TTR increased during the MEDeINR phase (65 to 69%), but was only significantly increased for one home (62% to 71%, p < 0.05). The percentage of time in supratherapeutic decreased from 14% to 11%, p = 0.08); there was little change for the subtherapeutic range (21% to 20%, p = 0.66). Overall, the average number of INR tests/30 days decreased from 4.2 to 3.1 (p < 0.0001) per resident after implementation of MEDeINR. Feedback received from LTC clinicians and staff was that the program decreased the work-load, improved confidence in management and decisions, and was generally easy to use.

Conclusion

Although LTC homes in our sample had TTR's that were relatively high prior to the intervention, the MEDeINR program represented a useful tool to promote optimal TTR, decrease INR venipunctures, streamline processes, and increase nurse and physician confidence around warfarin management. We have demonstrated that MEDeINR was a practical, usable clinical information system that can be incorporated into the LTC environment.

Patient Factors That Influence Warfarin Dose Response

Warfarin has long been the mainstay of oral anticoagulation therapy for the treatment and prevention of venous and arterial thrombosis. The narrow therapeutic index of warfarin, and the complex number of factors that influence international normalized ratio (INR) response, makes optimization of warfarin therapy challenging. Determination of the appropriate warfarin dose during initiation and maintenance therapy requires an understanding of patient factors that influence dose response: age, body weight, nutritional status, acute and chronic disease states, and changes in concomitant drug therapy and diet. This review will examine specific clinical factors that can affect the pharmacokinetics and pharmacodynamics of warfarin, as well as the role of pharmacogenetics in optimizing warfarin therapy.