Warfarin Dose Research Articles

Predicting in vivo Target Occupancy (TO) Profiles via PBPK-TO Modeling of Warfarin Pharmacokinetics in Blood: Importance of Low Dose Data and Prediction of Stereoselective Target Interactions.

Warfarin is well-recognized for its high-affinity and capacity-limited binding to the pharmacological target and undergoes target-mediated drug disposition (TMDD). Here, we developed a physiologically-based pharmacokinetic (PBPK) model that incorporated saturable target binding and other reported hepatic disposition components of warfarin. The PBPK model parameters were optimized by fitting to the reported blood PK profiles of warfarin with no stereoisomeric separation following oral dosing of racemic warfarin (0.1, 2, 5, or 10 mg) using the Cluster Gauss-Newton Method (CGNM). The CGNM-based analysis yielded multiple "accepted" sets for six optimized parameters, which were then used to simulate the warfarin blood PK and in vivo target occupancy (TO) profiles. When further analyses examined the impact of dose selection on uncertainty in parameter estimation by the PBPK modeling, the PK data from 0.1 mg dose (well below target saturation) was important in practically identifying the target binding-related parameters in vivo When stereoselective differences were incorporated for both hepatic disposition and target interactions, our PBPK modeling predicted that R-warfarin (of slower clearance and lower target affinity than S-warfarin) contributes to TO prolongation following oral dosing of racemic warfarin. Our results extend the validity of the approach by which the PBPK-TO modeling of blood PK profiles can yield TO prediction in vivo (applicable to the drugs with targets of high affinity and abundance and limited distribution volume via non-target interactions). Our findings support that model-informed dose selection and PBPK-TO modeling may aid in TO and efficacy assessment in preclinical and clinical phase-1 studies. Significance Statement The current PBPK modeling incorporated the reported hepatic disposition components and target binding of warfarin and analyzed the blood PK profiles from varying warfarin doses, practically identifying target binding-related parameters in vivo By implementing the stereoselective differences between R- and S-warfarin, our analysis predicted the role of R-warfarin in prolonging overall target occupancy. Our results extend the validity of analyzing blood PK profiles to predict target occupancy in vivo, which may guide efficacy assessment in preclinical and clinical phase-1 studies.

Time-to-event modeling for achieving a stable warfarin dose using genetic and non-genetic covariates.

Time-to-event modeling is gaining importance in drug dosage determination, particularly using pharmacometrics approaches. To evaluate the various time-to-event models for estimating the time to achieve a stable warfarin dose in the Bahraini population. A cross-sectional study evaluating the non-genetic and genetic covariates (single nucleotide polymorphisms (SNPs) in CYP2C9, VKORC1 and CYP4F2 genotypes) was conducted in patients receiving warfarin for at least 6 months. Time to achieving a stable dose of warfarin was defined as the duration (in days) from the day of initiating warfarin until 2 consecutive prothrombin time-international normalized ratio (PT-INR) values were observed in the therapeutic range with a gap of at least 7 days. Exponential, Gompertz, log-logistics, and Weibull models were tested, and the model with the lowest objective function value (OFV) was chosen. The covariate selection was carried out using the Wald test and OFV. A hazard ratio (HR) with a 95% confidence interval (95% CI) was estimated. A total of 218 participants were included in the study. The Weibull model was observed to have the lowest OFV (1989.82). The expected time to reach a stable dose in the population was 21.35 days. The CYP2C9 genotypes were identified as the only significant covariate. The HR (95% CI) for achieving a stable warfarin dose within 6 months of initiation for individuals with CYP2C9 *1/*2 was 0.2 (0.09, 0.3), 0.2 (0.1, 0.5) for CYP2C9 *1/*3, 0.14 (0.04, 0.6) for CYP2C9 *2/*2, 0.2 (0.03, 0.9) for CYP2C9 *2/*3, and 0.8 (0.45, 0.9) for those with the C/T genotype for CYP4F2. We estimated the population time-to-event parameters for achieving a stable warfarin dose in our population and observed CYP2C9 genotypes to be the main predictor covariate followed by CYP4F2. The influence of these SNPs needs to be validated in a prospective study and an algorithm to predict a stable warfarin dose and the time to achieve it needs to be developed.

Warfarin-Rifampin-Gene (WARIF-G) Interaction: ARetrospective, Genetic, Case-Control Study.

Warfarin is extensively metabolized by cytochrome P450 2C9 (CYP2C9). Concomitant use with the potent CYP2C9 inducer, rifampin, requires close monitoring and dosage adjustments. Although, in theory, warfarin dose increase should overcome this interaction, most reported cases over the last 50 years have not responded even to high warfarin doses, but some have responded to modest doses. To investigate the genetic polymorphisms' impact on this unexplained interpatient variability, we performed genotyping of CYP2C9, VKORC1, and CYP4F2 for warfarin and rifampin concomitant receivers from 2016 to 2022 at Hamad Medical Corporation, Doha, Qatar. We identified and included 36 patients: 22 responders and 14 nonresponders. Warfarin-responders were significantly more likely to have one or more warfarin-sensitizing CYP2C9/VKORC1 alleles than nonresponders (odds ratio=23.2, 95% confidence interval=3.2-195.6; P=0.0001). The mean genetic-based pre-interaction calculated dose was significantly lower for responders than for nonresponders (P < 0.001); and was negatively correlated with warfarin sensitivity index (WSI) (r=-0.58; P=0.0002). The median percentage time in therapeutic range and mean WSI were significantly higher in the warfarin-sensitizing CYP2C9/VKORC1 alleles carriers than noncarriers (P=0.017 and 0.0004, respectively). Whereas the warfarin-sensitizing CYP2C9/VKORC1 genotypes were associated with modest on-rifampin warfarin dose requirements, the noncarriers would have required more than double these doses to respond. Warfarin-sensitizing CYP2C9/VKORC1 genotypes and low genetic-based warfarin calculated doses were associated with higher warfarin sensitivity and better anticoagulation quality in patients receiving rifampin concomitantly.

A retrospective analysis of preemptive pharmacogenomic testing in 22,918 individuals from China

Pharmacogenomics (PGx) examines the influence of genetic variation on drug responses. With more and more Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines published, PGx is gradually shifting from the reactive testing of single gene toward the preemptive testing of multiple genes. But the profile of PGx genes, especially for the intra-country diversity, is not well understood in China. We retrospectively collected preemptive PGx testing data of 22,918 participants from 20 provinces of China, analyzed frequencies of alleles, genotypes and phenotypes of pharmacogenes, predicted drug responses for each participant, and performed comparisons between different provinces. After analyzing 15 pharmacogenes from CPIC guidelines of 31 drugs, we found that 99.97% of individuals may have an atypical response to at least one drug; the participants carry actionable genotypes leading to atypical dosage recommendation for a median of eight drugs. Over 99% of the participants were recommended a decreased warfarin dose based on genetic factors. There were 20 drugs with high-risk ratios from 0.18% to 58.25%, in which clopidogrel showed the highest high-risk ratio. In addition, the high-risk ratio of rasburicase in GUANGDONG (risk ratio (RR)=13.17, 95%CI:4.06-33.22, p < 0.001) and GUANGXI (RR=23.44, 95%CI:8.83-52.85, p < 0.001) were significantly higher than that in all provinces. Furthermore, the diversity we observed among 20 provinces suggests that preemptive PGx testing in different geographical regions in China may need to pay more attention to specific genes. These results emphasize the importance of preemptive PGx testing and provide essential evidence for promoting clinical implementation in China.

Global distribution of functionally important CYP2C9 alleles and their inferred metabolic consequences

BackgroundGenetic variability in the cytochrome P450 CYP2C9 constitutes an important predictor for efficacy and safety of various commonly prescribed drugs, including coumarin anticoagulants, phenytoin and multiple non-steroidal anti-inflammatory drugs (NSAIDs). A global map of CYP2C9 variability and its inferred functional consequences has been lacking.ResultsFrequencies of eight functionally relevant CYP2C9 alleles (*2, *3, *5, *6, *8, *11, *13 and *14) were analyzed. In total, 108 original articles were identified that included genotype data from a total of 81,662 unrelated individuals across 70 countries and 40 unique ethnic groups. The results revealed that CYP2C9*2 was most abundant in Europe and the Middle East, whereas CYP2C9*3 was the main reason for reduced CYP2C9 activity across South Asia. Our data show extensive variation within superpopulations with up to tenfold differences between geographically adjacent populations in Malaysia, Thailand and Vietnam. Translation of genetic CYP2C9 variability into functional consequences indicates that up to 40% of patients in Southern Europe and the Middle East might benefit from warfarin and phenytoin dose reductions, while 3% of patients in Southern Europe and Israel are recommended to reduce starting doses of NSAIDs.ConclusionsThis study provides a comprehensive map of the genetic and functional variability of CYP2C9 with high ethnogeographic resolution. The presented data can serve as a useful resource for CYP2C9 allele and phenotype frequencies and might guide the optimization of genotyping strategies, particularly for indigenous and founder populations with distinct genetic profiles.

Targeted next-generation sequencing of genes involved in Warfarin Pharmacodynamics and pharmacokinetics pathways using the Saudi Warfarin Pharmacogenetic study (SWAP).

Warfarin is an oral anticoagulant commonly used for treatment and prophylaxis against thromboembolic events. Warfarins's narrow therapeutic index window is one of the main challenges in clinical practice; thus, it requires frequent monitoring and dose adjustment to maintain patients' therapeutic range. Warfarin dose variation and response are attributed to several inter-and intra-individuals factors, including genetic variants in enzymes involved in warfarin pharmacokinetics (PK) and pharmacodynamics (PD) pathways. Thus, we aim to utilize the next-generation sequencing (NGS) approach to identify rare and common genetic variants that might be associated with warfarin responsiveness. A predesigned NGS panel that included 16 genes involved in Warfarin PK/PD pathways was used to sequence 786 patients from the Saudi Warfarin Pharmacogenetic Cohort (SWAP). Identified variants were annotated using several annotation tools to identify the pathogenicity and allele frequencies of these variants. We conducted variants-level association tests with warfarin dose. We identified 710 variants within the sequenced genes; 19% were novel variants, with the vast majority being scarce variants. The genetic association tests showed that VKORC1 (rs9923231, and rs61742245), CYP2C9 (rs98332238, rs9332172, rs1057910, rs9332230, rs1799853, rs1057911, and rs9332119), CYP2C19 (rs28399511, and rs3758581), and CYP2C8 (rs11572080 and rs10509681) were significantly associated with warfarin weekly dose. Our model included genetics, and non-genetic factors explained 40.1% of warfarin dose variation. The study identifies novel variants associated with warfarin dose in the Saudi population. These variants are more likely to be population-specific variants, suggesting that population-specific studies should be conducted before adopting a universal warfarin genotype-guided dosing algorithm.

Using an electronic medical record patient portal for warfarin self-management: Empowering children and parents

BackgroundMany children taking warfarin perform their international normalized ratio (INR) at home, with results phoned to a clinician who instructs warfarin dosing. Data suggest that parents can be supported to make warfarin dosing decisions themselves, a process known as patient self-management (PSM). ObjectivesThis study aimed to determine the suitability and acceptability of warfarin PSM in children using the Epic Patient Portal. MethodsChildren currently performing INR patient self-testing were eligible. Participation involved an individualized education session, adherence to the PSM program, and participation in phone interviews. Clinical outcomes (INR time in therapeutic range and safety outcomes), patient portal functionality, and family experience were assessed. The hospital human research ethics committee approved the study and consent was obtained from parents/guardians. ResultsTwenty-four families undertook PSM. The median age of children was 11 years and all children had congenital heart disease. A median of 13 INRs was uploaded to the portal per family (range, 8-47) across a 10-month period. Before PSM, the mean time the INR was in therapeutic range was 71%; this increased to 79.9% during PSM (difference: P < .001). No adverse events were encountered. Eight families participated in a phone interview. The major theme identified was empowerment; minor themes that emerged included “gaining knowledge,” “trust and responsibility builds confidence,” “saving time,” and “resources as a safety net.” ConclusionThis study demonstrates that communication via the Epic Patient Portal is satisfactory to families and offers a suitable option for PSM for children. Importantly, PSM empowers and builds confidence in families to facilitate management of their child’s health.

Supra-therapeutic Anticoagulation with Warfarin: A Cross-sectional Study.

To identify the extent and associated factors for patients with prolonged prothrombin time, international normalized ratio (PT-INR), and the dosage modifications were carried out with warfarin. Studies evaluating patients on warfarin with supratherapeutic anticoagulation are limited. It is vital to understand the management strategies for patients receiving warfarin who are bleeding and those with only supratherapeutic PT-INR. To evaluate the factors associated with supratherapeutic anticoagulation without bleeding with warfarin. A cross-sectional study was carried out on patients receiving long-term warfarin with at least one PT-INR value > 3.2. Percent time in therapeutic range (TTR) was calculated and National Institute for Health and Care Excellence (NICE) guidelines were adhered to defining anticoagulation control into good (> 65%) and poor (< 65%). One hundred and forty-four patients were recruited. Nearly half of the study population had PT-INR values between 3.2 and 3.9. On average, individuals had at least 4 times PT-INR values in the supratherapeutic range. Elderly patients were observed with a significant trend of supratherapeutic INR. Duration of therapy was significantly correlated with the risk of PT-INR > 4. Lower TTR was observed in patients with frequent PT-INR > 4 and those patients had significantly poor anticoagulation control. Duration of warfarin therapy and HAS-BLED scores were observed to be significant predictors of supratherapeutic INR. Large variations were observed in the modifications of warfarin dose carried out at various supratherapeutic INR values and consequently PTINR values. We observed that the majority of patients with supratherapeutic INR had their INR values between 3.2 and 3.9. Elderly patients, with higher HAS-BLED scores and prolonged duration of warfarin therapy, were observed with an increased risk of supratherapeutic anticoagulation. Careful dosage modifications are needed particularly in high-risk categories as mentioned above.

Relationship between elevated bilirubin levels and enhanced warfarin effects during biliary obstruction.

A marked prolongation of the prothrombin time-international normalized ratio (PT-INR) is frequently observed during biliary obstruction in patients using warfarin. The objective of this study was to identify factors associated with PT-INR prolongation during biliary obstruction in patients using warfarin. Among 44 patients using warfarin who had biliary obstruction, we retrospectively investigated warfarin doses and laboratory data before and during biliary obstruction. The primary outcome was the association between changes in PT-INR (ΔPT-INR) and changes in laboratory data before and during biliary obstruction. Median PT-INR was 1.59 (IQR 1.38-1.95) before biliary obstruction and 2.27 (IQR 1.60-3.49) during biliary obstruction, indicating significant prolongation during the obstruction (P < 0.001). ΔPT-INR showed strong positive correlations with change in total bilirubin (ΔT-Bil; ρ = 0.692, P < 0.001) and change in conjugated bilirubin (ΔC-Bil; ρ = 0.731, P < 0.001). ΔPT-INR showed a weak negative correlation with the change in albumin (ΔAlb; ρ = -0.371, P < 0.05). When ΔPT-INR was used as the dependent variable in multiple linear regression analysis, ΔT-Bil, ΔC-Bil, and ΔAlb were significantly associated with ΔPT-INR. PT-INR was prolonged during biliary obstruction in patients using warfarin, and changes in bilirubin levels were associated with ΔPT-INR. If biliary obstruction with markedly elevated bilirubin levels occurs, measuring PT-INR could lead to safer warfarin therapy.

Anticoagulation Management in Patients Receiving Warfarin at Private Cardiac Centers in Addis Ababa, Ethiopia.

Anticoagulants are the cornerstone therapy for thromboembolism prevention and treatment. Warfarin is the frequently prescribed drug and remains the oral anticoagulant of choice in low- and middle-income countries, including Ethiopia. It is a narrow therapeutic index drug that needs high-quality anticoagulation monitoring with frequent international normalization ratio (INR) testing. The study aimed to assess anticoagulation management with warfarin among adult outpatients at two selected private cardiac centers in Addis Ababa, Ethiopia. A hospital-based retrospective study design that enrolled 374 patients receiving warfarin was employed at two private cardiac centres in Addis Ababa, Ethiopia. The time in the therapeutic range (TTR) was calculated using the Rosendaal method. The data were analyzed using Statistical Package for Social Science version 25. The mean age of the patients was 57 years, and 218 (58.3%) participants were females. Out of 3384 INR tests, 1562 (46.5%) were within the therapeutic range and the mean percentage of TTR was 47.24%. Only 25.67% of the patients spent their TTR ≥ 65%. The present study revealed that dose adjustments were required 1764 times. In non-therapeutic INR values of 1764 that required warfarin dose adjustment, 59.7% of the doses were adjusted. About 262 (70.1%) of co-prescribed medications had interaction with warfarin. Sixty-four patients (17.11%) experienced bleeding events. Anticoagulation management with warfarin was suboptimal in private cardiac Addis Ababa, Ethiopia, private cardiac centers. Warfarin adjustment practice for nontherapeutic INR values was not minimal, and many patients encountered bleeding during their course of therapy.

Pharmacogenetics of warfarin dosing in Chinese adults with nonvalvular atrial fibrillation.

The guide for the use of genotype-guided warfarin dosing in patients for the treatment of non-valvular atrial fibrillation (AF) is still lacking. We aimed to evaluate whether genotype-guided warfarin dosing is superior to conventional clinical dosing for the outcomes of interest in Chinese patients. Our study consisted of 508 newly recruited and 471 existing Chinese AF patients. Among the total 979 patients, 585 patients received their dose of warfarin determined by a genetic and clinical factor (gene group), while the remaining 394 patients whose dosing was determined empirically in control group. We incorporated CYP2C9 and VKORC1 genotypes into the gene group. The international normalized ratio (INR) measurement and standard protocols were used for further dose adjustment in both groups. The primary outcomes were the percentage of time in the therapeutic range (%TTR) and INR during 12-month follow-up. Secondary safety outcome included bleeding and thrombotic events. Compared with the control group, the average TTR of the gene group was higher [68.4 ± 20.6% vs 48.5 ± 21.6%, P < 0.001]. The average INR monitoring times to reach the therapeutic time in the gene group was lower (P < 0.001). The risk ratios (RR) for cumulative incidence of total bleeding events, minor bleeding events, gastrointestinal bleeding, and intracerebral bleeding events were not significantly different between the two groups (P > 0.05). Comparing to the analysis using existing 471 patients, the analysis using total 979 patients showed that the gene group experienced a lower (RR 0.4 (95% CI 0.2 to 0.8), P = 0.008) incidence of cumulative ischemic stroke. Genotype-guided warfarin administration increases the average TTR, reaches higher TTR levels in the early anticoagulant phase, and significantly reduces the risk of ischemic stroke events.

Genomewide Association Study Identifies Copy Number Variants Associated With Warfarin Dose Response and Risk of Venous Thromboembolism in African Americans.

The anticoagulant warfarin is commonly used to control and prevent thrombotic disorders, such as venous thromboembolism (VTE), which disproportionately afflicts African Americans. Despite the importance of copy number variants (CNVs), few studies have focused on characterizing and understanding their role in drug response and disease risk among African Americans. In this study, we conduct the first genome-wide analysis of CNVs to more comprehensively account for the contribution of genetic variation in warfarin dose requirement and VTE risk among African Americans. We used hidden Markov models to detect CNVs from high-throughput single-nucleotide polymorphism arrays for 340 African American participants in the International Warfarin Pharmacogenetics Consortium. We identified 11,570 CNVs resulting in 2,038 copy number variable regions (CNVRs) and found 3 CNVRs associated with warfarin dose requirement and 3 CNVRs associated with VTE risk in African Americans. CNVRs 1q31.2del and 6q14.1del were associated with increased warfarin dose requirement (β=11.18 and 4.94, respectively; Pemp =< 0.002); CNVR 19p13.31del was associated with decreased warfarin dose requirement (β=-1.41, Pemp =0.0004); CNVRs (2p22.1del and 5q35.1-q35.2del) were found to be associated with increased risk of VTE (odds ratios (ORs)=1.88 and 14.9, respectively; Pemp ≤0.02); and CNVR 10q26.12del was associated with a decreased risk of VTE (OR=0.6; Pemp =0.05). Modeling of the 10q26.12del in HepG2 cells revealed that this deletion results in decreased fibrinogen gene expression, decreased fibrinogen and WDR11 protein levels, and decreased secretion of fibrinogen into the extracellular matrix. We found robust evidence that CNVRs could contribute to warfarin dose requirement and risk of VTE in African Americans and for 10q26.3del describe a possible pathogenic mechanism.

Automated warfarin dose prediction for Asian, American, and Caucasian populations using a deep neural network

Existing warfarin dose prediction algorithms based on pharmacogenetics and clinical parameters have not been used clinically due to the absence of external validation, lack of assessment for clinical utility, and high risk of bias. Moreover, given the high degree of heterogeneity across different datasets used to develop these algorithms, it is unsurprising that prediction errors remain high, and dosing accuracy is dependent on specific ethnic populations. To circumvent these challenges, deep neural models are increasingly used to improve the precision and accuracy of warfarin dose predictions. Hence, this study sought to develop a deep learning-based model using a well-established curated dataset of over 6000 patients from the International Warfarin Pharmacogenomics Consortium (IWPC). Clinically-relevant input data such as physical attributes, medical conditions, concomitant medications, genotype status of functional warfarin genetic polymorphisms, and therapeutic INR were entered followed by applying a unique and robust training and validation method. The deep model yielded a low average mean absolute error (MAE) of 7.6 mg/week and a relatively low mean percentage of error of 40.9% in Asians, 14.2 mg/week MAE and 36.9% in African Americans, and 12.7 mg/week MAE and 45.4% mean percentage of error in White Caucasians. This model also resulted in 36.4% of all patients with a predicted dose within 20% of the administered dose. Hence, our proposed deep model provides an alternative to predicting warfarin dose in the clinical setting upon validation in ethnically-similar datasets.

Comparison of Maintenance Dose Predictions by Warfarin Dosing Algorithms Based on Chinese and Western Patients.

Warfarin has a long record of safe and effective clinical use, and it remains one of the most commonly prescribed drugs for the prevention and treatment of thromboembolic conditions even in the era of direct oral anticoagulants. To address its large interindividual variability and narrow therapeutic window, the Clinical Pharmacogenetics Implementation Consortium has recommended using pharmacogenetic dosing algorithms, such as the ones developed by the International Warfarin Pharmacogenetics Consortium (IWPC) and by Gage et al, to dose warfarin when genotype information is available. In China, dosing algorithms based on local patient populations have been developed and evaluated for predictive accuracy of warfarin maintenance doses. In this study, percentage deviations of doses predicted by 15 Chinese dosing algorithms from that by IWPC and Gage algorithms were systematically evaluated to understand the differences between Chinese and Western algorithms. In general, dose predictions by Chinese dosing algorithms tended to be lower than those predicted by IWPC or Gage algorithms for the most prevalent VKORC1 and CYP2C9 genotypes in the Chinese population. The extent of negative prediction deviation appeared to be largest in the younger age group with smaller body weight. Our findings are consistent with previous reports that Asians have a higher sensitivity to warfarin and require lower doses than Western populations.

Warfarin hypersensitivity in the internist's practice: a case report

Anticoagulants are widely used in clinical practice to reduce the risk of cardiovascular events. However, there are associated clinical conditions that require coagulation system monitoring due to an increased risk of bleeding. In clinical practice, cases of warfarin hypersensitivity due to gene polymorphisms are known. Taking warfarin in such a situation is often manifested by massive bleeding that threatens the patient's life. Sixty seven-years-old female patient was admitted to the internal medicine department of Rostov State Medical University clinic in March 2022. The day before, she noted severe abdominal pain, loose bloody stool. An outpatient examination revealed an increase in international normalized ratio to 9,42, thrombin time &gt;30 sec. There were no signs of primary gastrointestinal pathology. According to anamnesis, on January 21, 2022, the patient underwent mechanical aortic valve replacement, in connection with which warfarin was prescribed at a dose of 2,5 mg/day. After establishing hypocoagulation, warfarin was discontinued. A pharmacogenetic analysis was performed, which established the carriage of polymorphisms of cytochrome P450 system genes, the homozygous mutation 1075A&gt;C (CYP2C9 (*3/*3)), and the heterozygous mutation of the vitamin K reductase gene VKORC1 G(-1639)A (VKORC1 GA). The individual dosage of warfarin was calculated according to International Warfarin Pharmacogenetics Consortium guidelines, which was 9 mg/week. After adjusting the dose of warfarin, the level of international normalized ratio decreased to 3,61, thrombin time to 13 sec. The patient was discharged with recommendations to follow an individual warfarin regimen and monitor coagulation parameters. The presence of hypersensitivity to warfarin is not a reason for its complete withdrawal in situations requiring longterm anticoagulation. In this regard, it is necessary for the doctor to be vigilant when prescribing warfarin to a patient, understanding the causes and methods for diagnosing hypersensitivity to warfarin, and timely correction of its dosage.

A retrospective study on pattern of pulmonary embolism in chestdepartment-Assiut University

BackgroundPulmonary embolism (PE) is a severe and fatal disease, and its incidence varies widely between countries.AimTo determine the frequency of PE in the Chest Department of Assiut University Hospital, to determine the risk factors and effective treatment, and to study the outcome of the disease in this locality.Patients and methodsIn this retrospective study, 222 patients suspected to have PE were screened for PE and underwent computed tomography-pulmonary angiogram to confirm or exclude a clinical suspicion of PE. All of the following were collected from patient data sheets: history, clinical examination data, ECG abnormalities, chest radiograph, Doppler ultrasound, echocardiography, chest ultrasound, laboratory reports, treatment lines, and the outcome in the form of mortality, ICU admission, length of hospital stay, and discharge to home.ResultsOf the included PE cases, all of them received heparin followed by warfarin, except for 10 patients who received rivaroxaban without any toxicity. Warfarin dose needed to reach therapeutic international normalized ratio (between 2 and 3) was 3–9 mg in –85% of the patients. A total of 71 patients needed admission to ICUs, and of them, 24 patients died, but there were no recorded deaths in the ward. Housewives represented 43.7%. The most common symptoms were dyspnea (84%) and chest pain (62%). Tachypnea was the most frequent sign (72%), and hypotension was observed in 13.5%. PE was common in patients with diabetes mellitus, patients with chronic obstructive pulmonary disease (COPD), patients with deep-vein thrombosis, and those who use oral contraceptive pills (18.5, 17.5, 17.1, and 14.4%, respectively). Regarding echocardiography findings, 16.4% of our patients were cardiomyopathic, 74.4% had mild to moderate pulmonary hypertension, with severe pulmonary hypertension detected in only 7% of patients. Computed tomography-pulmonary angiogram revealed main pulmonary artery embolism in 49.09% of the patients, and in 60 (27%) patients, it was bilateral.ConclusionPE is frequent in Upper Egypt. Diabetes and COPD are the most important risk factors of PE. Death owing to PE is markedly associated with OHS and COPD morbidity.

Autosplenectomy may be a good prognostic sign in sickle cell diseases

Background: Sickle cell diseases (SCDs) are inborn and destructive processes on vascular endothelium, particularly at the capillaries. Methods: Patients with red blood cells (RBCs) transfusions of less than 50 units in their lives were put into the first and 50 units or higher were put into the second groups. Results: There were 224 patients in the first and 92 patients in the second groups. Mean ages were similar in them (28.9 vs 30.0 years, respectively, p&gt;0.05). The male ratio was higher in the second group (45.5% vs 64.1%, p&lt;0.001). In contrast to the lower prevalence of autosplenectomy (56.2% vs 45.6%, p&lt;0.05), painful crises per year, digital clubbing, chronic obstructive pulmonary disease (COPD), leg ulcers, stroke, chronic renal disease (CRD), and coronary heart disease (CHD) were all higher in the second group (p&lt;0.05 for all). Conclusion: The sickled or just hardened RBCs-induced capillary endothelial damage initiates at birth, and terminates with multiorgan failures even at childhood. Although RBCs suspensions and corticosteroids in acute, and aspirin with an anti-inflammatory dose plus low-dose warfarin plus hydroxyurea both in acute and chronic phases decrease severity, survivals are still shortened in both genders, dramatically. In contrast to the lower prevalence of autosplenectomy, painful crises per year, digital clubbing, COPD, leg ulcers, stroke, CRD, and CHD were higher in the second group. So there may be an inverse relationship between prevalence of autosplenectomy and severity of SCDs, and spleen may act as a chronic inflammatory focus as a filter of blood for these abnormally hardened RBCs. Key words: Sickle cell diseases, sickled or just hardened red blood cells, capillary endothelial edema, myocardial infarction, stroke, sudden deaths, autosplenectomy

As a good prognostic sign, Autosplenectomy is higher in females in Sickle Cell Diseases

Background: Sickle cell diseases (SCDs) are inborn and destructive processes on vascular endothelium, particularly at the capillaries. Methods: All patients with the SCDs were included. Results: We studied 222 males and 212 females with similar ages (30.8 vs 30.3 years, p&gt;0.05, respectively). Although the higher prevalence of autosplenectomy (50.4% vs 53.3%, p&lt;0.05), transfused units of red blood cells (RBCs) in their lives (48.1 vs 28.5, p=0.000), disseminated teeth losses (5.4% vs 1.4%, p&lt;0.001), ileus (7.2% vs 1.4%, p&lt;0.001), cirrhosis (8.1% vs 1.8%, p&lt;0.001), leg ulcers (19.8% vs 7.0%, p&lt;0.001), clubbing (14.8% vs 6.6%, p&lt;0.001), coronary heart disease (CHD) (18.0% vs 13.2%, p&lt;0.05), chronic renal disease (CRD) (9.9% vs 6.1%, p&lt;0.05), chronic obstructive pulmonary disease (COPD) (25.2% vs 7.0%, p&lt;0.001), and stroke (12.1% vs 7.5%, p&lt;0.05) were all lower in females. Conclusion: The sickled or just hardened RBCs-induced capillary endothelial damage initiates at birth, and terminates with multiorgan failures even at childhood. Although RBCs suspensions and corticosteroids in acute, and aspirin with an anti-inflammatory dose plus low-dose warfarin plus hydroxyurea both in acute and chronic phases decrease severity, survivals are still shortened in both genders, dramatically. Although the higher prevalence of autosplenectomy, transfused units of RBCs in their lives disseminated teeth losses, ileus, cirrhosis, leg ulcers, clubbing, CHD, CRD, COPD, and stroke were all lower in females. So there may be an inverse relationship between autosplenectomy and severity of SCDs, and spleen may act as a chronic inflammatory focus as a filter of blood for these sickled or just hardened RBCs. Key words: Sickled or just hardened red blood cells, capillary endothelial edema, myocardial infarction, stroke, sudden deaths, autosplenectomy, female gender

Male Gender alone may be a bad Prognostic Factor in Sickle Cell Diseases

Background: Sickle cell diseases are inborn and destructive processes on vascular endothelium, particularly at the capillaries. Methods: All patients were included. Results: We studied 222 males and 212 females with similar ages (30.8 vs 30.3 years, p&gt;0.05, respectively). Smoking (23.8% vs 6.1%, p&lt;0.001), alcohol (4.9% vs 0.4%, p&lt;0.001), transfused red blood cells (RBCs) in their lives (48.1 vs 28.5 units, p=0.000), disseminated teeth losses (5.4% vs 1.4%, p&lt;0.001), chronic obstructive pulmonary disease (COPD) (25.2% vs 7.0%, p&lt;0.001), ileus (7.2% vs 1.4%, p&lt;0.001), cirrhosis (8.1% vs 1.8%, p&lt;0.001), leg ulcers (19.8% vs 7.0%, p&lt;0.001), clubbing (14.8% vs 6.6%, p&lt;0.001), coronary heart disease (CHD) (18.0% vs 13.2%, p&lt;0.05), chronic renal disease (CRD) (9.9% vs 6.1%, p&lt;0.05), and stroke (12.1% vs 7.5%, p&lt;0.05) were all higher, and autosplenectomy (50.4% vs 53.3%, p&lt;0.05) and mean age of mortality were lower in males (30.2 vs 33.3 years, p&lt;0.05). Conclusion: The sickled or just hardened RBCs-induced capillary endothelial damage initiates at birth, and terminates with multiorgan failures even at childhood. Although RBCs suspensions and corticosteroids in acute, and aspirin with an anti-inflammatory dose plus low-dose warfarin plus hydroxyurea both in acute and chronic phases decrease severity, survivals are still shortened in both genders, dramatically. Transfused units of RBCs in their lives, disseminated teeth losses, COPD, ileus, cirrhosis, leg ulcers, clubbing, CHD, CRD, and stroke were all higher, and autosplenectomy and mean age of mortality were lower in males which can not be explained by effects of smoking and alcohol alone at these younger mean ages, relatively. Key words: Sickle cell diseases, sickled or just hardened red blood cells, capillary endothelial edema, myocardial infarction, stroke, sudden deaths, male gender

Comparison of medication adherence to different oral anticoagulants: population-based cohort study

ObjectivePrevious observational studies have yielded conflicting results on whether medication adherence differs between patients receiving warfarin and direct oral anticoagulants (DOACs). Importantly, no study has adequately accounted for warfarin dosing...