Anticoagulation in the elderly

Comparing the post-operative complications following surgery for hip fracture of patients who were on warfarin versus patients who were on novel oral anticoagulants: a meta-analysis

BACKGROUND

Hip fracture in the elderly is considered a significant public health burden due to a high rate of mortality and this is globally being seen as a serious concern. However, comorbidities requiring anticoagulants are of particular concern in the post-operative setting. In this analysis, we aimed to systematically compare the post-operative complications following surgery for hip fracture of patients who were on warfarin versus patients who were on novel oral anticoagulants (NOACs).

METHODS

Web of Science, EMBASE, Google Scholar, the Cochrane databases, MEDLINE, and http://www.

CLINICALTRIALS

gov were searched for relevant studies from January to February 2024. The post-operative complications were considered the endpoints in this study. Risk ratios (RR) with 95% confidence intervals (CIs) were used to represent the data following statistical analysis. Weighted mean difference (WMD) calculated with mean and standard deviation, with 95% CIs, was used to represent the result for mean length of hospital stay.

RESULTS

A total number of 15,019 participants with hip fracture were included in this analysis. Eleven thousand two hundred and fifteen (11,215) participants were on warfarin therapy prior to fracture and surgery, whereas 3804 participants were on NOACs. Results of this analysis showed that the risks of post-operative mortality (RR, 1.03; 95% CI, 0.92-1.16; P = 0.57), deep vein thrombosis (RR, 1.10; 95% CI, 0.41-2.98; P = 0.84), pulmonary embolism (RR, 1.17; 95% CI, 0.44-3.10; P = 0.75), stroke (RR, 1.25; 95% CI, 0.23-6.71; P = 0.80) and myocardial infarction (RR, 0.42; 95% CI, 0.03-6.98; P = 0.55) were not significantly different in patients who underwent surgery for hip fracture and who were on warfarin versus on NOACs. The risks of infection (RR, 0.90; 95% CI, 0.28-2.93; P = 0.87) and blood transfusion (RR, 1.08; 95% CI, 0.80-1.45; P = 0.62) were also similarly manifested. However, the length of hospital stay [WMD, - 0.93; 95% CI, - 1.83 to 0.03; P = 0.04] was significantly less in patients who were on NOACs in comparison to those who were on warfarin.

CONCLUSIONS

The post-operative complications following surgery for hip fracture of patients who were on warfarin versus patients who were on NOACs were similar. However, those patients who were on warfarin had a significantly longer length of hospital stay.

Ventriculoperitoneal Shunt Placement Safety in Idiopathic Normal Pressure Hydrocephalus: Anticoagulated Versus Non-Anticoagulated Patients

BACKGROUND

Many patients with idiopathic normal pressure hydrocephalus (iNPH) have medical comorbidities requiring anticoagulation that could negatively impact outcomes. This study evaluated the safety of ventriculoperitoneal shunt placement in iNPH patients on systemic anticoagulation versus those not on anticoagulation.

METHODS

Patients >60 years of age with iNPH who underwent shunting between 2018 and 2022 were retrospectively reviewed. Baseline demographics, comorbidities (quantified by modified frailty index and Charlson comorbidity index), anticoagulant/antiplatelet agent use (other than aspirin), operative details, and complications were collected. Outcomes of interest were the occurrence of postoperative hemorrhage and overdrainage.

RESULTS

A total of 234 patients were included in the study (mean age 75.22 ± 6.04 years; 66.7% male); 36 were on anticoagulation/antiplatelet therapy (excluding aspirin). This included 6 on Warfarin, 19 on direct Xa inhibitors, 10 on Clopidogrel, and 1 on both Clopidogrel and Warfarin. Notably, 70% of patients (164/234) used aspirin alone or combined with anticoagulation or clopidogrel. Baseline modified frailty index was similar between groups, but those on anticoagulant/antiplatelet therapy had a higher mean Charlson comorbidity index (2.67 ± 1.87 vs. 1.75 ± 1.84; P = 0.001). Patients on anticoagulants were more likely to experience tract hemorrhage (11.1 vs. 2.5%; P = 0.03), with no significant difference in the rates of intraventricular hemorrhage or overdrainage-related subdural fluid collection.

CONCLUSIONS

Anticoagulant and antiplatelet agents are common in the iNPH population, and patients on these agents experienced higher rates of tract hemorrhage following ventriculoperitoneal shunt placement; however, overall hemorrhagic complication rates were similar.

Anticoagulation in the Elderly

Oral anticoagulation has been shown to provide great benefit in preventing and treating thromboembolic disorders. The challenges of oral anticoagulation management in the elderly involve balancing the risks of bleeding versus the benefits of a life-saving treatment. Due to the complex nature of warfarin, therapy must be individualized with frequent monitoring, re-education, and adjustments based on concurrent illness and drug therapy. This review focuses on the use of warfarin, including indications, dosing recommendations, drug and dietary interactions, and reversal of anticoagulation. Methods to determine bleeding risks in this population and barriers that interfere with the prescribing of warfarin are discussed. Strategies to improve patient outcome and reduce adverse events are provided to assist clinicians in their decision-making skills. The potential advantages of anticoagulation clinics are summarized with regards to coordinating the care and minimizing the risks of anticoagulant therapy. The role of new-generation anticoagulants is also discussed as to their place in therapy.

Improving the management of warfarin in aged-care facilities utilising innovative technology: a proof-of-concept study

Objective

In aged-care facilities (ACFs) monitoring of warfarin can be logistically challenging and International Normalised Ratio (INR control) is often suboptimal. We aimed to determine whether an integrated information and communications technology system and the use of point-of-care (POC) monitors by nursing staff could improve the INR control of aged-care facility residents who take warfarin.

Methods

Nursing staff identified residents who were prescribed warfarin in participating ACFs. A computer program (MedePOC) was developed to store and transmit INR results from the ACFs to general practitioners (GPs) for dosage adjustment. Nursing staff received training in the use of the CoaguChek XS point-of-care INR monitor and the MedePOC software. Following a run-in phase, eligible patients were monitored weekly for up to 12 weeks. The primary outcome was the change in the time in therapeutic range (TTR) in the intervention phase compared to the TTR in the 12 months preceding the study. All GPs, nursing staff and patients were surveyed for their experiences and opinions of the project.

Key findings

Twenty-four patients and 19 GPs completed the trial across six ACFs. The mean TTR for all patients improved non-significantly from 58.9 to 60.6% (P = 0.79) and the proportion of INR tests in range improved non-significantly from 57.1 to 64.1% (P = 0.21). The mean TTR improved in 14 patients (58%) and in these patients the mean absolute improvement in TTR was 23.1%. A post hoc analysis of the INR data using modified therapeutic INR ranges to reflect the dosage adjustment practices of GPs suggested that the intervention did lead to improved INR control. The MedePOC program and POC monitoring was well received by nursing staff.

Conclusions

Weekly POC INR monitoring conducted in ACFs and electronic communication of the results and warfarin doses resulted in non-significant improvements in INR control in a small cohort of elderly residents. Further research involving modification to the communication strategy and a longer follow-up period is warranted to investigate whether this strategy can improve INR control and clinical outcomes in this vulnerable population.

Hospitalization for vitamin-K-antagonist-related bleeding: treatment patterns and outcome

BACKGROUND

Bleeding complications are common side effects of vitamin-K antagonist (VKA) therapy. Data on the in-hospital management and outcomes of these bleeding events are scarce and information is mostly derived from trial cohorts.

OBJECTIVES

The objective was to collect data on the management and clinical outcome of hospitalizations owing to VKA-related bleeding in real-world practice.

PATIENTS AND METHODS

We performed a multicenter observational cohort study involving 21 secondary and tertiary care hospitals in the administrative district Dresden, Saxony, Germany throughout the year 2005. All consenting patients presenting with VKA-related bleeding complications were included. No exclusion criteria applied. Data were collected at admission, at discharge and at 90 days to evaluate resource consumption, length of hospital stay and risk factors for in-hospital- and 3-month mortality.

RESULTS

Two hundred and ninety patients were included (median age 74 years; 50.7% male). The main indications for VKA therapy were atrial fibrillation (63.4%), prior thromboembolism (18.6%) and mechanical heart valves (11.4%), and most common bleeding localizations were large hematoma (23.1%), upper gastrointestinal (GI) tract (17.9%) and intracranial bleeding (14.1%). On hospital admission, the median International Normalized Ratio (INR) was 3.0 (range 0.9-12.5, interquartile range [IQR] 2.1-3.9). In-hospital mortality was 7.6% with impaired renal function as the most relevant risk factor. At 90 days mortality was 14.1% and 15.3% of survivors were help-dependent.

CONCLUSIONS

VKA-related bleeding leading to hospitalization is associated with long hospitalization, relevant resource utilization, high mortality or persistent sequlae. Patient-related factors such as impaired renal function, chronic cardiac or pulmonary disease and dementia are predictive of in-hospital and 3-month mortality.

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.

The risks of warfarin use in the elderly

The use of warfarin in the elderly, particularly for stroke prevention in chronic atrial fibrillation, is steadily increasing. Although the benefits of warfarin are greatest in the elderly, so are the risk of adverse outcomes and the difficulties of anticoagulant management. Clinical systems need to improve to counter this therapeutic dilemma, as warfarin is likely to remain the only widely available oral anticoagulant for the foreseeable future. Aspects that require attention are: the careful selection of patients in whom treatment with warfarin is appropriate; initiating therapy in a low dose (e.g., 2.5-5 mg/day); thorough education of patients and carers; close monitoring, especially with any change in the patient's regular drug therapy; involving patients more in the management of their warfarin therapy (self-monitoring/management in suitable patients); and ongoing review of the appropriateness of therapy as circumstances change.

Vitamin K antagonists and direct thrombin inhibitors: present and future

Warfarin and related compounds are efficacious and safe in a variety of clinical thrombotic disorders; however, these drugs have a narrow therapeutic window, whereby inadequate therapy is associated with an increased thrombotic risk and overanticoagulation is associated with bleeding. Therefore, attempts have been made to develop alternatives to warfarin. Ximelagatran, an oral direct thrombin inhibitor, has been shown to be as efficacious and safe as warfarin for the prevention and treatment of different thrombotic disorders. This article reviews the pharmacology of the coumarins, the most commonly used vitamin K antagonists, and the practical aspects regarding their use in the management of thrombotic disorders. The future role of the oral direct thrombin inhibitor ximelagatran also is reviewed.

Dosing Practices and Risk Factors for Bleeding in Patients Receiving Enoxaparin for the Treatment of an Acute Coronary Syndrome

OBJECTIVES

To describe dosing practices and to identify risk factors for bleeding in patients with an acute coronary syndrome (ACS) who received treatment with enoxaparin.

DESIGN

Retrospective chart review.

SETTING

Coronary care unit of a tertiary-care teaching hospital.

PATIENTS

Patients with a discharge diagnosis of an ACS who received at least one dose of enoxaparin, 1 mg/kg, were eligible for this study. Enoxaparin dosing practices, factors that might influence the safety of enoxaparin administration, and bleeding events were documented. Multivariable regression analysis was used to identify independent predictors of bleeding in this clinical setting.

RESULTS

Of 208 patients with an ACS who received enoxaparin, 48 patients (23%) received a dose that was > 10% or < 10% of the recommended 1 mg/kg dose, 18 patients (9%) did not have body weight documentation to guide enoxaparin dosing, and 17 patients (8%) had significant renal impairment (serum creatinine > 150 micromol/L), with the potential for bioaccumulation of enoxaparin. There were 35 bleeding events (17%), of which 8 events (4%) were major. Risk factors for any bleeding (major or minor) were increasing patient age (odds ratio [OR], 1.57; 95% confidence interval [CI], 1.13 to 2.20), coadministered nonsteroidal anti-inflammatory or antiplatelet drug therapy (OR, 2.38; 95% CI, 1.06 to 5.38), and number of enoxaparin doses (OR, 2.15; 95% CI, 1.25 to 3.68). Risk factors for major bleeding were increasing patient age (OR, 2.56; 95% CI, 1.05 to 6.28) and coadministered clopidogrel (OR, 7.70; 95% CI, 1.16 to 51.9).

CONCLUSION

In this clinical practice assessment of patients with an ACS, the use of enoxaparin was suboptimal, with the potential to increase bleeding complications. Coadministered clopidogrel, other drugs that affect hemostasis, and increasing age conferred an increased bleeding risk.

Coumarin therapy in thrombosis

Oral anticoagulants are the most commonly used agents in the long-term prophylaxis and treatment of arterial and venous thrombotic disorders. As new and expanded indications for their use, such as the prevention of recurrent myocardial infarction or the treatment of systemic embolism in atrial fibrillation, are developed, the use of oral anticoagulants is rising. Also, in North America, oral anticoagulants are used commonly for preventing venous thromboembolism following orthopedic surgery. This article reviews the pharmacology of warfarin sodium, the most commonly used oral anticoagulant in North America, and discusses practical aspects of the use of this agent in thrombotic disorder management.