Identifying Potential Predictors of High-Quality Oral Anticoagulation Assessed by Time in Therapeutic International Normalized Ratio Range: A Prospective, Long-Term, Single-Center, Observational Study

Attainment of Target in Therapeutic Range of International Normalized Ratio and Correlates Among Patients on Warfarin Therapy at Jimma Medical Center, Jimma, Ethiopia

PURPOSE

Warfarin is effective therapy to prevent thromboembolic complications of venous thromboembolism, atrial fibrillation, and cardiac thrombus, among valvular heart diseases, including in patients treated with prostheses and/or repair. Its optimum effect is achieved when the international normalized ratio (INR) is in the target therapeutic range, but a subtherapeutic level increases risk of thromboembolism and complications. This study aimed to assess the attainment of target therapeutic range, proportion, and factors associated with subtherapeutic level of warfarin.

METHODS

A hospital-based cross-sectional study was conducted at Jimma Medical Center in Jimma, Ethiopia, from October 1, 2020 through December 30, 2021. All patients on warfarin and attending Medical Follow-Up Clinics of Jimma Medical Center during the study period were included. Data were collected using structured questionnaires and then analyzed using EpiData Manager software, version 3.1 (EpiData Association). χ2 Tests and logistic regression models were used to assess relationships among variables.

FINDINGS

Of 196 patients on warfarin, ∼60% were taking it for atrial fibrillation, followed by deep venous thrombosis, women accounted for 61.7% of patients, and mean (SD) age was 43 (7) years. Most patients (61.7%) lived in rural areas and 44.9% farmed to earn a living. Most of the study participants (51.5%) had a very low monthly income of less than USD50. Most of the patients (n = 107 [54.6%]) were advised on dietary selections while on warfarin and approximately two-thirds (n = 70 [65.4%]) were adherent to the advice. Most participants (n = 118 [60.2%]) were poorly adherent to warfarin therapy and more than two-thirds of them discontinued warfarin for financial reasons. Mean (SD) duration of warfarin therapy was 15.53 (18.92) months (range 1-90 months). Most of the respondents (n = 109 [55.6%]) had subtherapeutic INR and 21 (10.7%) were in the supratherapeutic range. Although the mean (SD) time in therapeutic range was 25.03% (24.17% [range 0-80%]), in most patients (n = 166 [84.7%]), it was <60%. Poor adherence (adjusted odds ratio = 6.13; 95% CI, 3.31-28.10), shorter duration of warfarin (<12 months; adjusted odds ratio = 0.104; 95% CI, 0.012-0.875), and presence of comorbidity (adjusted odds ratio = 0.035; 95% CI, 0.004-0.323) were significantly associated with subtherapeutic INR.

IMPLICATIONS

Attainment of therapeutic INR among patients on warfarin therapy is suboptimal. This was evidenced by a significant number of patients with low time in therapeutic range, as well as INR. Poor adherence to warfarin therapy, shorter duration since initiation of warfarin, and presence of comorbid illnesses were significantly associated with subtherapeutic INR. This can lead to complications of atrial fibrillation, including thrombus formation and subsequent cardioembolic stroke, venous thromboembolism, and others, leading to morbidity, increased mortality, and poor quality of life. Therefore, providing health education and treatment for comorbidities may improve adherence, which may also improve attainment of therapeutic INR and reduce complications and improve quality of life.

Integrated analysis of clinical and genetic factors on the interindividual variation of warfarin anticoagulation efficacy in clinical practice

AIM

The anticoagulation effect of warfarin is usually evaluated by percentage of time in therapeutic range (PTTR), which is negatively correlated with the risk of warfarin adverse reactions. This study aimed to explore the effects of genetic and nongenetic factors on anticoagulation efficacy of warfarin during different therapeutic range.

METHODS

We conducted an observational retrospective study aiming at evaluating the impact of clinical and genetic factors on PTTR from initial to more than six months treatment. This analysis included patients with heart valve replace (HVR) surgery who underwent long-term or life-long time treatment with standard-dose warfarin for anticoagulation control in Second Xiangya Hospital. All patients were followed for at least 6 months. We genotyped single nucleotide polymorphisms in VKORC1 and CYP2C9 associated with altered warfarin dose requirements and tested their associations with PTTR.

RESULTS

A total of 629 patients with intact clinical data and available genotype data were enrolled in this study, and only 38.63% patients achieved good anticoagulation control (PTTR > 0.6). Clinical factors, including male gender, older age, overweight, AVR surgery and stroke history, were associated with higher PTTR. Patients with VKORC1 -1639AA genotype had significantly higher PTTR level compared with GA/GG genotype carriers only in the first month of treatment. Patients with CYP2C9*3 allele had higher PTTR compared with CYP2C9*1*1 carriers. Moreover, compared with VKORC1 -1639 AG/GG carriers, INR > 4 was more likely to be present in patients with AA genotype. The frequency of CYP2C9*1*3 in patients with INR > 4 was significantly higher than these without INR > 4.

CONCLUSION

We confirmed the relevant factors of warfarin anticoagulation control, including genetic factors (VKORC1 -1639G > A and CYP2C9*3 polymorphisms) and clinical factors (male gender, older age, overweight, AVR surgery and stroke history), which could be helpful to individualize warfarin dosage and improve warfarin anticoagulation control during different treatment period.

Management Strategies Following Slightly Out of Range INRs: Watchful Waiting vs. Dose Changes

Watchful waiting describes maintaining a warfarin dose after a slightly out-of-range INR and retesting within the following 2 weeks.

Although a warfarin dose change is more effective in producing a therapeutic INR, our study supports ACCP guidelines for watchful waiting.

Patients’ international normalized ratios (INRs) often fall slightly out of range. In these cases, the American College of Chest Physicians (ACCP) guidelines suggest maintaining the current warfarin dose and retesting the INR within the following 2 weeks (watchful waiting). We sought to determine whether watchful waiting or dose changes for slightly out-of-range INRs is more effective in obtaining in-range INRs at follow-up. INRs and management strategies of warfarin-treated patients within the Michigan Anticoagulation Quality Improvement Initiative registry were analyzed. Management strategies included watchful waiting or dose changes. INRs slightly out of range (target range 2.0-3.0) and their associated management were identified. Multilevel mixed-effects logistic regression was used to estimate the probability of the next INR being in range, adjusted for clustering due to multiple out-of-range INRs per patient. A total of 45 351 slightly out-of-range INRs (ranging 1.50-1.99 and 3.01-3.49) from 8288 patients were identified. The next INR was slightly less likely to be in range with watchful waiting than with a dose change (predicted probabilities 58.9% vs 60.0%, P = 0.024). Although a significant statistical difference was detected in the probabilities of the next INR being back in range when managed by a dose change compared with watchful waiting following a slightly out-of-range INR, the magnitude of the difference was small and unlikely to represent clinical importance. Our study supports the current guideline recommendations for watchful waiting in cases of slightly out-of-range INRs values.

Thromboembolism, Bleeding, and Mortality Incidence of Direct Oral Anticoagulants Versus Warfarin Postbariatric Surgery

BACKGROUND

There is no randomized controlled trial comparing direct oral anticoagulants (DOACs) and warfarin following bariatric surgery to date. The mortality, thromboembolism, and bleeding risk of DOACs in comparison with warfarin following bariatric surgery remains unclear. We aimed to provide a clinical comparison between DOACs and warfarin for these 3 prespecified outcomes.

METHODS

A systematic literature search was performed on November 10, 2019, using PubMed, Embase, clinicaltrial.gov, and Cochrane databases. Studies with adult patients who were on either warfarin or DOACs following bariatric surgery and reported the incidence of thromboembolism, bleeding, or mortality were included. Pooled incidence for these prespecified outcomes and its 95% confidence interval (CI) were calculated for each drug separately using the random-effects model, along with a nonadjusted P value comparing the 2 subgroups.

RESULTS

A total of 11 studies (805 patients) were included. Comparing DOACs to warfarin, the following pooled incidences were observed for mortality (DOACs: 3.0%; 95% CI 0.4%-18.6% versus warfarin: 1.5%; 95% CI 0.8%-2.9%; P value comparing the 2 subgroups = .38), thromboembolism (DOACs: 4.9%; 95% CI 1%-21.1% versus warfarin: 1.5%; 95% CI 0.8%-2.9%; P value = .18), and bleeding (DOACs: 3.9%; 95% CI 0.7%-18.2% versus warfarin: 11.3%; 95% CI 5.7%-21.4%; P value = .23).

CONCLUSION

The results of our meta-analysis remain hypothesis-generating, providing rationale for future randomized controlled trial design or well-designed comparative observational studies. Currently, it does not support the change in the current recommendation from warfarin to DOACs following bariatric surgery.

The short-term effect of the COVID-19 pandemic on the management of warfarin therapy

Aim    The aim of this study was to investigate the short-term effect of the COVID-19 pandemic on the management of warfarin therapy used for atrial fibrillation (AF) and prosthetic valve disease.Material and methods    The study included 139 Atrial fibrillation (AF) patients and 173 prosthetic valve patients (PVP) who were using warfarin. The time in therapeutic range (TTR), International Normalized Ratio (INR) averages, the numbers of INR tests, and the non-adherence to INR monitoring (NIM) were compared for the pre-covid period (PCP) and the COVID-19 period (CP). Also, adherence to warfarin therapy was evaluated with a questionnaire.Results    For all patients, the INR values were higher in the CP (2.47 vs 2.60, p&lt;0.001), and the NIM percentage was higher (19.2 % vs 71.5 %, p&lt;0.001) in the CP. The number of INR tests was lower during the CP (p&lt;0.001).The percentage of patients with TTR≥70 % was lower during the CP (41.7 % vs 33 % p=0.017). Subgroup analysis showed that for PVP, TTR values and the percentage of patients with TTR ≥70 % were similar in both the PCP and CP periods. The questionnaire showed that for 94.1 % of respondents, the major cause of NIM in the CP was the COVID-19 pandemic. However, during the CP, adherence to warfarin medication was high (95.5 %).Conclusion    Lower TTR during the COVID-19 pandemic can increase bleeding and thromboembolic cases.Therefore, patients taking warfarin should be followed more closely, and more practical ways should be considered for INR testing.

Low Performance of a Clinical-Genetic Model in the Estimation of Time in Therapeutic Range in Acenocoumarol-Adherent Patients with Nonvalvular Atrial Fibrillation: The Quality of Anticoagulation Challenge

BACKGROUND

Anticoagulation with vitamin K antagonists continues to be a challenging task given the difficulty of achieving a correct time in therapeutic range (TTR). The SAMeTT2R2 score has been proposed to identify patients that will be good responders. In this study we aimed to analyse clinical and genetic factors involved in a correct level of anticoagulation in patients with atrial fibrillation and thereby potentially improve the diagnostic performance of SAMeTT2R2 score.

METHODS

We prospectively included 212 consecutive patients with nonvalvular atrial fibrillation under treatment with acenocoumarol for at least 6 months that were attended in a cardiology outpatient clinic and were categorized as adherent to medication. We carried out a multivariate regression analysis to detect the independent predictive factors of good control. In all patients VKORC1, CYP2C9⁎2, CYP2C9⁎3, and MIR133A2 genotyping was performed.

RESULTS

A total of 128 (60.4%) patients presented TTR <70% (average TTR = 63.2). We identified body mass index (OR 0.94, 95%CI 0.89-0.99, p=0.032) and regular vitamin K intake (OR 0.53, 95%CI 0.28-0.99, p= 0.046) as independent predictors of poor anticoagulation control. The discriminatory power of a clinical-genetic model derived from our cohort was significantly better compared to the SAMeTT2R2 score (C-statistic 0.658 versus 0.524, p<0.001).

CONCLUSIONS

In our study the SAMeTT2R2 score revealed a poor ability in the prediction of TTR. Besides SAMeTT2R2, body mass index and possibly vitamin K intake should be taken into account when deciding the optimal anticoagulation strategy. The information provided by the identified genotypes was marginal.

Comparing the Cost Effectiveness of Non-vitamin K Antagonist Oral Anticoagulants with Well-Managed Warfarin for Stroke Prevention in Atrial Fibrillation Patients at High Risk of Bleeding

BACKGROUND

Several studies have compared the cost effectiveness of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin using results from clinical trials evaluating NOACs. However, the time in therapeutic range (TTR) of warfarin groups ranged across clinical trials, and all were below the therapeutic goal of 70%. We compared the cost effectiveness of edoxaban 60 mg, apixaban 5 mg, dabigatran 150 mg, dabigatran 110 mg, rivaroxaban 20 mg, and well-managed warfarin with a TTR of 70% in preventing stroke among patients with atrial fibrillation at high risk of bleeding.

METHODS

For the six treatments, we used a Markov state-transition model to quantify lifetime costs in $US and effectiveness in quality-adjusted life-years (QALYs). We simulated relative risk ratios of clinical events with each NOAC versus warfarin with a TTR of 70% using published regression models that predict how the incidence of thrombotic or hemorrhagic events changes for each unit change in TTR. We re-ran our analysis for two other estimates of TTR: 65 and 75%.

RESULTS

Treatment with edoxaban 60 mg cost $US127,520/QALY gained compared with warfarin with a TTR of 70% and cost $US41,860/QALY gained compared with warfarin with a TTR of 65%. However, warfarin with a TTR of 75% was more effective and less expensive than all NOACs. For three levels of TTR, apixaban 5 mg, dabigatran 150 mg, dabigatran 110 mg, and rivaroxaban 20 mg were dominated strategies.

CONCLUSIONS

The comparative cost effectiveness of edoxaban and warfarin is highly sensitive to TTR. At the $US100,000/QALY willingness-to-pay threshold, our results suggest that warfarin is the most cost-effective treatment for patients who can achieve a TTR of 70%.

Quality and predictors of anticoagulant control with vitamin K antagonist for stroke prevention in atrial fibrillation

Supplementary Material to this article is available online at www.thrombosis-online.com.

Satisfaction, quality of life and perception of patients regarding burdens and benefits of vitamin K antagonists compared with direct oral anticoagulants in patients with nonvalvular atrial fibrillation

AIM

To compare the satisfaction of patients treated with vitamin K antagonists (VKA) with that of patients treated with direct oral anticoagulants (DOACs) and to determine the impact on quality of life of both treatments in patients with nonvalvular atrial fibrillation (NVAF).

METHODS

Cross-sectional multicenter study in which outpatients with NVAF completed the ACTS (Anti-Clot Treatment Scale), SAT-Q (Satisfaction Questionnaire) and EQ-5D-3L (EuroQol 5 dimensions questionnaire, 3 level version) questionnaires.

RESULTS

The study population comprised 1337 patients, of whom 587 were taking DOACs and 750 VKAs. Compared with VKAs, DOACs were more commonly prescribed in patients with a history of stroke and in patients with a higher thromboembolic risk. The study scores were as follows: SAT-Q: 63.8 ± 17.8; EQ-5D-3L total score: 75.6 ± 20.9; visual analog scale: 63.1 ± 20.6; ACTS Burdens: 51.8 ± 8.4 and ACTS Benefits: 11.9 ± 2.4. The ACTS Burdens score and ACTS Benefits score were higher with DOACs than with VKAs (54.83 ± 6.11 vs 49.50 ± 9.15; p < 0.001 and 12.36 ± 2.34 vs 11.48 ± 2.46; p < 0.001 respectively).

CONCLUSION

NVAF patients treated with oral anticoagulants had many comorbidities and a high thromboembolic risk. Satisfaction and quality of life with oral anticoagulants were high, although they were both better with DOACs than with VKAs.

Factors Affecting the Quality of Anticoagulation With Vitamin K Antagonists in Venous Thromboembolism Patients

Introduction:

Treatment of venous thromboembolism (VTE) is classically based on oral vitamin K antagonists (VKAs). Due to the disadvantages and side effects of these drugs, monitoring the quality of anticoagulation by assessing time within therapeutic range (TTR) is recommended. Variables altering the TTR in patients with VTE are yet to be determined. The aim of this study was to analyze the quality of anticoagulation in patients with VTE treated with VKAs and to identify factors associated with poor-quality anticoagulation.

Methods:

A retrospective observational study was performed in a cohort of 94 patients diagnosed with VTE undergoing treatment with VKAs. The TTR at 6 months was analyzed by the Rosendaal method. Univariate and a multivariate logistic regression analyses were performed to unravel factors that increase risk of poor-quality anticoagulation.

Results:

The TTR at 6 months in this cohort was 60.5%; 54 patients had a TTR < 65%. In the univariate analysis, female sex, age ≥ 65 years, and renal impairment were significantly associated with poor-quality anticoagulation. However, in the multivariate logistic regression model, only renal impairment was independently associated with poor-quality anticoagulation (odds ratio = 3.31, 95% confidence interval [1.049, 10.486], p = .041).

Discussion:

The average quality of anticoagulation was 60.5%, and a high percentage of patients had a quality of anticoagulation below recommended levels. Study findings indicate that renal impairment is an independent risk factor for poor-quality anticoagulation in patients with VTE treated with VKAs.

Educational Level, Anticoagulation Quality, and Clinical Outcomes in Elderly Patients with Acute Venous Thromboembolism: A Prospective Cohort Study

Whether the level of education is associated with anticoagulation quality and clinical outcomes in patients with acute venous thromboembolism (VTE) is uncertain. We thus aimed to investigate the association between educational level and anticoagulation quality and clinical outcomes in elderly patients with acute VTE. We studied 817 patients aged ≥65 years with acute VTE from a Swiss prospective multicenter cohort study (09/2009-12/2013). We defined three educational levels: 1) less than high school, 2) high school, and 3) post-secondary degree. The primary outcome was the anticoagulation quality, expressed as the percentage of time spent in the therapeutic INR range (TTR). Secondary outcomes were the time to a first recurrent VTE and major bleeding. We adjusted for potential confounders and periods of anticoagulation. Overall, 56% of patients had less than high school, 25% a high school degree, and 18% a post-secondary degree. The mean percentage of TTR was similar across educational levels (less than high school, 61%; high school, 64%; and post-secondary, 63%; P = 0.36). Within three years of follow-up, patients with less than high school, high school, and a post-secondary degree had a cumulative incidence of recurrent VTE of 14.2%, 12.9%, and 16.4%, and a cumulative incidence of major bleeding of 13.3%, 15.1%, and 15.4%, respectively. After adjustment, educational level was neither associated with anticoagulation quality nor with recurrent VTE or major bleeding. In elderly patients with VTE, we did not find an association between educational level and anticoagulation quality or clinical outcomes.

Vitamin K antagonist use: evidence of the difficulty of achieving and maintaining target INR range and subsequent consequences

Vitamin K antagonists (VKAs) are effective oral anticoagulants that are titrated to a narrow therapeutic international normalized ratio (INR) range. We reviewed published literature assessing the impact of INR stability - getting into and staying in target INR range - on outcomes including thrombotic events, major bleeding, and treatment costs, as well as key factors that impact INR stability.

A time in therapeutic range (TTR) of ≥65 % is commonly accepted as the definition of INR stability. In the real-world setting, this is seldom achieved with standard-of-care management, thus increasing the patients’ risks of thrombotic or major bleeding events. There are many factors associated with poor INR control. Being treated in community settings, newly initiated on a VKA, younger in age, or nonadherent to therapy, as well as having polymorphisms of CYP2C9 or VKORC1, or multiple physical or mental co-morbid disease states have been associated with lower TTR. Clinical prediction tools are available, though they can only explain <10 % of the variance behind poor INR control.

Clinicians caring for patients who require anticoagulation are encouraged to intensify diligence in INR management when using VKAs and to consider appropriate use of newer anticoagulants as a therapeutic option.

Quality of anticoagulation control among patients with atrial fibrillation: An experience of a tertiary care center in Saudi Arabia

Background

Atrial fibrillation (AF) is the most common chronic rhythm disorder. Patients with AF are at an increased risk of ischemic stroke. Therefore, optimal anticoagulation is essential to reduce the risk of stroke. The aim of this study was to assess the level of anticoagulation control achieved in patients with nonvalvular AF receiving medical care in a tertiary care hospital.

Methods

This was a retrospective cohort study in ambulatory care clinics at tertiary care hospital in Saudi Arabia. We included 110 nonvalvular AF patients treated with warfarin for at least 3 months at King Abdulaziz Medical City, Riyadh, Saudi Arabia, between May 1, 2012, and July 31, 2012. Thereafter, international normalized ratio results were collected for 1 year. Anticoagulation control was assessed by calculating time within therapeutic range (TTR) as per the Rosendaal method.

Results

The mean age was 64.9 ± 16.5 years; 60.9% were female. The mean TTR was 59%. Almost one third of the patients (32.7%) had poor anticoagulation control; TTR of <50%. Poor anticoagulation control was significantly associated with higher CHADS2 (congestive heart failure, hypertension, age, diabetes, stroke) score (p = 0.043). TTR was not significantly different between men and women. Similarly, TTR was not associated with age or duration of anticoagulation. There was no adequate information to assess the effect of other factors such as diet, compliance, and level of education on anticoagulation. Thirty-one patients (28.2%) had a history of prior stroke. The overall quality of anticoagulation was not significantly different between patients with and without stroke, (TTR was 56.3% and 60.1%, respectively; p = 0.46).

Conclusion

Quality of anticoagulation in patients with AF receiving medical care in a tertiary care hospital was suboptimal, with nearly 40% of the time spent outside the therapeutic range. Methods to improve anticoagulation control among patients with AF should be implemented.

Anticoagulation Control in Patients With Nonvalvular Atrial Fibrillation Attended at Primary Care Centers in Spain: The PAULA Study

INTRODUCTION AND OBJECTIVES

To determine the current status of anticoagulation control in patients with nonvalvular atrial fibrillation treated with vitamin K antagonists in the primary care setting in Spain.

METHODS

The PAULA study was a multicenter cross-sectional/retrospective observational study conducted throughout Spain. The study included patients with nonvalvular atrial fibrillation who had been receiving vitamin K antagonist therapy during the past year and were attended at primary care centers. International normalized ratio (INR) values over the past 12 months were recorded. The degree of anticoagulation control was defined as the time the patient had remained within the therapeutic range and was determined by both the direct method (poor control < 60%) and by the Rosendaal method (poor control < 65%).

RESULTS

The study assessed 1524 patients (mean age, 77.4 ± 8.7 years; 48.6% women; 64.2% in permanent atrial fibrillation; CHADS2 mean, 2.3 ± 1.2; CHA2DS2-VASc, 3.9 ± 1.5, and HAS-BLED, 1.6 ± 0.9). The mean number of INR readings recorded per patient was 14.4 ± 3.8. A total of 56.9% of patients had adequate INR control according to the direct method and 60.6% according to the Rosendaal method. The multivariate analysis identified the following predictors for poor INR control: female sex, dietary habits potentially affecting anticoagulation with vitamin K antagonists, multidrug therapy, and a history of labile INR.

CONCLUSIONS

Approximately 40% of patients (43.1% by the direct method and 39.4% by the Rosendaal method) with nonvalvular atrial fibrillation who were receiving anticoagulation therapy with vitamin K antagonists in primary care in Spain had poor anticoagulation control during the previous 12 months.

Comparison of two approaches of INR-follow-up and determinants of INR-stability

INTRODUCTION

Patients with atrial fibrillation (AF) and treated with coumarins need a close follow-up of the international normalized ratio (INR)-values. This can be done by the general practitioner (GP) or by a haematologist in an outpatient hospital clinic.

OBJECTIVE

To compare both ways of follow-up and to investigate determinants of stable INR-patterns.

METHODS

Cross-sectional single-centre study in patients with AF treated at the UZ Brussel, a university hospital in Brussels. Of the 113 patients included in the study, 71 had their INR followed-up by their GP and 42 similar patients were followed-up by a haematologist. Data of these 113 patients were further analysed to identify possible determinants for stable INR-values.

RESULTS

The time in therapeutic range (TTR) did not significantly differ between both groups. However, patients in the GP-group had significantly more INR-values under 2.0 compared to patients from the haematologist-group (P =  0.044), whereas patients in the haematologist-group had significantly more INR-values above 3.0 compared to patients from the GP-group (P = 0.038). Reimbursement costs of both ways of follow-up were comparable, but the out-of-pocket costs for the patient were lower in the GP-group. The time since AF diagnosis was the only significant determinant predicting a higher TTR.

CONCLUSION

Both approaches of follow-up seem to lead to the same TTR, yielding no reason to advocate one approach above the other. However, the patient costs were lower when followed-up by the GP.

Comorbidities against quality control of VKA therapy in non-valvular atrial fibrillation: a French national cross-sectional study

Background

Given the prevalence of non-valvular atrial fibrillation in the geriatric population, thromboembolic prevention by means of vitamin K antagonists (VKA) is one of the most frequent daily concerns of practitioners. The effectiveness and safety of treatment with VKA correlates directly with maximizing the time in therapeutic range, with an International Normalized Ratio (INR) of 2.0-3.0. The older population concentrates many of factors known to influence INR rate, particularly concomitant medications and concurrent medical conditions, also defined as comorbidities.

Objective

Determine whether a high burden on comorbidities, defined by a Charlson Comorbidity Index (CCI) of 3 or greater, is associated a lower quality of INR control.

Study-Design

Cross-sectional study.

Settings

French geriatric care units nationwide.

Participants

2164 patients aged 80 and over and treated with vitamin K antagonists.

Measurements

Comorbidities were assessed using the Charlson Comorbidity Index (CCI). The recorded data included age, sex, falls, kidney failure, hemorrhagic event, VKA treatment duration, and the number and type of concomitant medications. Quality of INR control, defined as time in therapeutic range (TTR), was assessed using the Rosendaal method.

Results

487 patients were identified the low-quality control of INR group. On multivariate logistic regression analysis, low-quality control of INR was independently associated with a CCI ≥3 (OR = 1.487; 95% CI [1.15; 1.91]). The other variables associated with low-quality control of INR were: hemorrhagic event (OR = 3.151; 95% CI [1.64; 6.07]), hospitalization (OR = 1.614, 95% CI [1.21; 2.14]).

Conclusion

An elevated CCI score (≥3) was associated with low-quality control of INR in elderly patients treated with VKA. Further research is needed to corroborate this finding.