Antithrombin testing and treatment in pregnancy: Their real-world relationship to clinical outcomes.

BACKGROUND: Antithrombin (AT) deficiency is a severe thrombophilia associated with increased rates of maternal morbidity, mortality, and greater healthcare resource utilization during pregnancy and postpartum. METHODS: Two large U.S. healthcare databases were queried for women aged 15-44 with delivery-related encounters: Cerner Real-World Data (CRWD, 01/01/2000-12/31/2021) and Premier Healthcare Database (PHD, 01/01/2016-01/01/2019). Individuals receiving cardiopulmonary bypass were excluded. Three cohorts were created: 1) Individuals who had AT levels tested any time between 9-months pre- through 3-months post-delivery (CRWD Test Cohort); 2) individuals prescribed AT concentrate (ATc) within 1-year pre- or 1-year post-delivery in CRWD (CRWD Medication Cohort); and 3) the same criteria as 2) applied to PHD (PHD Medication Cohort). RESULTS: There were 5411 individuals in the CRWD Test Cohort, 13 in the CRWD Medication Cohort and 38 in the PHD Medication Cohort. Demographic and baseline clinical characteristics were similar across cohorts. AT level testing occurred pre-delivery in 47.9 % of the CRWD Test Cohort and 23.1 % of the CRWD Medication Cohort. ATc was administered during the delivery hospitalization to 0.1 %, 23.1 % and 50.0 % of the CRWD Test, CRWD Medication, and PHD Medication Cohorts, respectively. Across cohorts, 5.4-7.9 % of individuals experienced thrombosis during the delivery-related encounter. Mean (SD) total costs for delivery through 1-year post-delivery were $190,894 ($276,893) with $123,763 ($177,122) of total costs related to abnormal coagulation. CONCLUSION: Opportunities exist to enhance the care of pregnant individuals with low AT levels throughout pregnancy, aiming for optimal maternal outcomes.

Antithrombin concentrates may benefit cardiopulmonary bypass patients with suspected heparin resistance: A retrospective analysis of real-world data.

Background: Heparin resistance is a common complication of surgical patients requiring anticoagulation, such as those undergoing cardiopulmonary bypass (CPB). Treatments to address heparin resistance include supplementation of antithrombin (AT) or fresh frozen plasma (FFP). This retrospective database analysis compared key outcomes in suspected heparin-resistant patients undergoing CPB treated with AT or FFP. Methods: De-identified United States electronic health records (Cerner Health Facts®) were queried. International Classification of Diseases (ICD-9/10) codes were used to determine CPB procedures and FFP administration. AT administration was identified using medication data, while a combination of lab and medication data examining activated clotting times detected heparin resistance in FFP patients. Adult inpatients (≥18 years old) seen between 2001 and 2018 were included. Differences in mortality, intensive care unit (ICU) length of stay (LOS), and hospital-free days (using a 30-day post-discharge period) were assessed with univariate models as well as adjusted logistic regression models controlling for patient characteristics and Charlson Comorbidity Index (CCI) scores. Results: Of the 502 patients identified, 247 received AT and 255 received FFP. The FFP cohort was associated with a higher CCI compared to the AT cohort (3.3 ± 2.4 vs. 2.3 ± 2.0, P < .001). The AT cohort was associated with a 71% (Odds Ratio [OR]: 0.29, 95% Confidence Interval [CI]: P = .003) and 66% (OR: 0.34, 95% CI: P = .01) reduction in mortality when compared to FFP using univariate and adjusted logistic regression models, respectively. Similarly, use of AT also showed a 22% shorter ICU LOS (P = .02) and 10% more hospital-free days in the 30 days following discharge (P = .004) according to the univariate models, though statistical significance was absent within adjusted models in both ICU LOS (P = .08) and hospital-free days (P = .53). Conclusions: Compared to FFP, AT use suggests a reduction in the odds of mortality in suspected heparin-resistant patients undergoing CPB, though larger prospective studies are necessary to elucidate potential differences in hospital-free days or ICU LOS across treatment modalities.

Correction to: Routine clinical care data for population pharmacokinetic modeling: the case for Fanhdi/Alphanate in hemophilia A patients.

The article Routine clinical care data for population pharmacokinetic modeling: the case for Fanhdi/Alphanate in hemophilia A patients, written by Pierre Chelle, Cindy H. T. Yeung, Santiago Bonanad, Juan Cristóbal Morales Muñoz, Margareth C. Ozelo, Juan Eduardo Megías Vericat, Alfonso Iorio, Jeffrey Spears, Roser Mir, Andrea Edginton, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 21 May 2019 without open access.

Routine clinical care data for population pharmacokinetic modeling: the case for Fanhdi/Alphanate in hemophilia A patients.

Fanhdi/Alphanate is a plasma derived factor VIII concentrate used for treating hemophilia A, for which there has not been any dedicated model describing its pharmacokinetics (PK). A population PK model was developed using data extracted from the Web-Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) project. WAPPS-Hemo provided individual PK profiles for hemophilia patients using sparse observations as provided in routine clinical care by hemophilia centers. Plasma factor activity measurements and covariate data from hemophilia A patients on Fanhdi/Alphanate were extracted from the WAPPS-Hemo database. A population PK model was developed using NONMEM and evaluated for suitability for Bayesian forecasting using prediction-corrected visual predictive check (pcVPC), cross validation, limited sampling analysis and external evaluation against a population PK model developed on rich sampling data. Plasma factor activity measurements from 92 patients from 12 centers were used to derive the model. The PK was best described by a 2-compartment model including between subject variability on clearance and central volume, fat free mass as a covariate on clearance, central and peripheral volumes, and age as covariate on clearance. Evaluations showed that the developed population PK model could predict the PK parameters of new individuals based on limited sampling analysis and cross and external evaluations with acceptable precision and bias. This study shows the feasibility of using real-world data for the development of a population PK model. Evaluation and comparison of the model for Bayesian forecasting resulted in similar results as a model developed using rich sampling data.

Performing and interpreting individual pharmacokinetic profiles in patients with Hemophilia A or B: Rationale and general considerations.

OBJECTIVES: In a separate document, we have provided specific guidance on performing individual pharmacokinetic (PK) studies using limited samples in persons with hemophilia with the goal to optimize prophylaxis with clotting factor concentrates. This paper, intended for clinicians, aims to describe how to interpret and apply PK properties obtained in persons with hemophilia. METHODS: The members of the Working Party on population PK (PopPK) of the ISTH SSC Subcommittee on Factor VIII and IX and rare bleeding disorders, together with additional hemophilia and PK experts, completed a survey and ranking exercise whereby key areas of interest in the field were identified. The group had regular web conferences to refine the manuscript's scope and structure, taking into account comments from the external feedback to the earlier document. RESULTS: Many clinical decisions in hemophilia are based on some form of explicit or implicit PK assessment. Individual patient PK profiles can be analyzed through traditional or PopPK methods, with the latter providing the advantage of fewer samples needing to be collected on any prophylaxis regimen, and without the need the for a washout period. The most useful presentation of PK results for clinical decision making are a curve of the factor activity level over time, the time to achieve a certain activity level, or related parameters like half-life or exposure (AUC). Software platforms have been developed to deliver this information to clinicians at the point of care. Key characteristics of studies measuring average PK parameters were reviewed, outlining what makes a credible head-to-head comparison among different concentrates. Large data collections of PK and treatment outcomes currently ongoing will advance care in the future. CONCLUSIONS: Traditionally used to compare different concentrates, PK can support tailoring of hemophilia treatment by individual profiling, which is greatly simplified by adopting a PopPK/Bayesian method and limited sampling protocol.

Cost analysis of plasma-derived factor VIII/von Willebrand factor versus recombinant factor VIII for treatment of previously untreated patients with severe hemophilia A in the United States.

BACKGROUND: Inhibitor development to factor VIII (FVIII) hemophilia therapy results in increased complications and substantial economic costs. The SIPPET study, the first randomized controlled trial to compare the immunogenicity of plasma-derived FVIII (pdFVIII)/von Willebrand factor (VWF) and recombinant-DNA-derived FVIII (rFVIII), demonstrated higher inhibitor rates in previously untreated patients (PUPs) treated with rFVIII than in PUPs treated with pdFVIII/VWF. OBJECTIVE: To quantify the economic impact of treating PUPs with pdFVIII/VWF vs rFVIII. METHODS: An Excel-based clinical and economic model was developed from a US healthcare payer perspective and run over a 5-year period. The analysis utilized a cohort approach to model patient treatment and outcomes over a monthly cycle to quantify differences in costs of FVIII, bypassing agents, and hospitalizations for serious bleeds. Rates of high-titer inhibitor development were obtained from the SIPPET study. Patients developing high-titer inhibitors were treated with immune tolerance induction (ITI). Patients who developed low-titer inhibitors and those who did not develop inhibitors continued their usual FVIII treatment. Patients who were successfully treated with ITI returned to FVIII treatment, while unsuccessfully treated patients received bypassing agents. Total costs per treated patient were estimated and a one-way sensitivity analysis was conducted to quantify the impact of parameter uncertainty on the model outcomes. RESULTS: Total cumulative costs per patient over 5 years were $834,621 for pdFVIII/VWF patients and $1,237,163 for rFVIII patients, representing a total saving of $402,542 per patient over the 5-year period, for an average annual saving of $80,508 per patient. CONCLUSIONS: Based on data from the SIPPET study, this analysis found that initiating FVIII treatment in severe hemophilia A PUPs with pdFVIII/VWF has the potential to offer substantial cost savings to healthcare payers, amounting to a one-third reduction in costs.

Issues in the Diagnosis and Management of Hereditary Antithrombin Deficiency.

OBJECTIVE: To review insights gained in the past several years about hereditary antithrombin (AT) deficiency and to outline approaches to the management of patients with AT deficiency in the acute and chronic settings. DATA SOURCES: An extensive literature search of Scopus (January 2008-April 2016) was performed for the terms congenital antithrombin deficiency, inherited antithrombin deficiency, or hereditary antithrombin deficiency Additional references were identified by reviewing literature citations. STUDY SELECTION: All relevant English-language case reports, reviews, clinical studies, meeting abstracts, and book chapters assessing hereditary AT deficiency were included. DATA SYNTHESIS: AT deficiency significantly increases the risk of venous thromboembolism (VTE). The risk of VTE is particularly high during pregnancy, the postpartum period, and following major surgery. Effective clinical management includes determination of the appropriate type and duration of antithrombotic therapy (ie, AT replacement for acute situations) while minimizing the risk of bleeding. For persons newly diagnosed with AT deficiency, age, lifestyle, concurrent medical conditions, family history, and personal treatment preferences can be used to individualize patient management. Patients should be informed of the risks associated with hormonal therapy, pregnancy, surgical procedures, and immobility, which further increase the risk of VTE in patients with AT deficiency. CONCLUSION: AT deficiency poses the highest risk for VTE among the hereditary thrombophilias, often requiring long-term anticoagulation. Undertaking an evaluation for hereditary thrombophilia is controversial; however, a diagnosis of VTE in association with AT deficiency can have management implications. An important treatment option for patients with this disorder in high-risk situations is AT concentrate.

Comorbidities and inhibitors in adult patients with haemophilia: issues, costs and management strategies.

Along with greater life expectancy in patients with haemophilia has been an increase in associated haemophilia-related (arthropathy, osteoporosis, viral infections) and age-related (cardiovascular disease, renal disease, cancer and others) comorbidities, many of which are only just emerging as the population ages. At present, experience in managing these comorbidities is limited. As the demographic shift continues, haemophilia care centres can expect to encounter more patients with greater levels of complexity. In the absence of evidence-based information to guide the management of adult patients with haemophilia, it is important that the scientific position be reviewed on a regular basis. To this end, several topics relevant to the clinical management of adult patients with haemophilia were examined in a symposium entitled Comorbidities and inhibitors in adult patients with haemophilia: issues, costs and management strategies held on 11 February 2015 in Helsinki, Finland, in conjunction with the 8th Annual Congress of the European Association for Haemophilia and Allied Disorders. This article is a summary of that event.