The InterModel Vigorish as a Lens for Understanding (and Quantifying) the Value of Item Response Models for Dichotomously Coded Items.

The deployment of statistical models-such as those used in item response theory-necessitates the use of indices that are informative about the degree to which a given model is appropriate for a specific data context. We introduce the InterModel Vigorish (IMV) as an index that can be used to quantify accuracy for models of dichotomous item responses based on the improvement across two sets of predictions (i.e., predictions from two item response models or predictions from a single such model relative to prediction based on the mean). This index has a range of desirable features: It can be used for the comparison of non-nested models and its values are highly portable and generalizable. We use this fact to compare predictive performance across a variety of simulated data contexts and also demonstrate qualitative differences in behavior between the IMV and other common indices (e.g., the AIC and RMSEA). We also illustrate the utility of the IMV in empirical applications with data from 89 dichotomous item response datasets. These empirical applications help illustrate how the IMV can be used in practice and substantiate our claims regarding various aspects of model performance. These findings indicate that the IMV may be a useful indicator in psychometrics, especially as it allows for easy comparison of predictions across a variety of contexts.

WHOLE GENOME TARGETED ENRICHMENT AND SEQUENCING OF HUMAN-INFECTING CRYPTOSPORIDIUM spp.

Cryptosporidium spp. are protozoan parasites that cause severe illness in vulnerable human populations. Obtaining pure Cryptosporidium DNA from clinical and environmental samples is challenging because the oocysts shed in contaminated feces are limited in quantity, difficult to purify efficiently, may derive from multiple species, and yield limited DNA (<40 fg/oocyst). Here, we develop and validate a set of 100,000 RNA baits (CryptoCap_100k) based on six human-infecting Cryptosporidium spp. (C. cuniculus, C. hominis, C. meleagridis, C. parvum, C. tyzzeri, and C. viatorum) to enrich Cryptosporidium spp. DNA from a wide array of samples. We demonstrate that CryptoCap_100k increases the percentage of reads mapping to target Cryptosporidium references in a wide variety of scenarios, increasing the depth and breadth of genome coverage, facilitating increased accuracy of detecting and analyzing species within a given sample, while simultaneously decreasing costs, thereby opening new opportunities to understand the complex biology of these important pathogens.

WHOLE GENOME TARGETED ENRICHMENT AND SEQUENCING OF HUMAN-INFECTING CRYPTOSPORIDIUM spp.

Cryptosporidium spp. are protozoan parasites that cause severe illness in vulnerable human populations. Obtaining pure Cryptosporidium DNA from clinical and environmental samples is challenging because the oocysts shed in contaminated feces are limited in quantity, difficult to purify efficiently, may derive from multiple species, and yield limited DNA (<40 fg/oocyst). Here, we develop and validate a set of 100,000 RNA baits (CryptoCap_100k) based on six human-infecting Cryptosporidium spp. ( C. cuniculus , C. hominis , C. meleagridis , C. parvum , C. tyzzeri , and C. viatorum ) to enrich Cryptosporidium spp. DNA from a wide array of samples. We demonstrate that CryptoCap_100k increases the percentage of reads mapping to target Cryptosporidium references in a wide variety of scenarios, increasing the depth and breadth of genome coverage, facilitating increased accuracy of detecting and analyzing species within a given sample, while simultaneously decreasing costs, thereby opening new opportunities to understand the complex biology of these important pathogens.

Phylogenomic reconstruction of Cryptosporidium spp. captured directly from clinical samples reveals extensive genetic diversity.

Cryptosporidium is a leading cause of severe diarrhea and mortality in young children and infants in Africa and southern Asia. More than twenty Cryptosporidium species infect humans, of which C. parvum and C. hominis are the major agents causing moderate to severe diarrhea. Relatively few genetic markers are typically applied to genotype and/or diagnose Cryptosporidium. Most infections produce limited oocysts making it difficult to perform whole genome sequencing (WGS) directly from stool samples. Hence, there is an immediate need to apply WGS strategies to 1) develop high-resolution genetic markers to genotype these parasites more precisely, 2) to investigate endemic regions and detect the prevalence of different genotypes, and the role of mixed infections in generating genetic diversity, and 3) to investigate zoonotic transmission and evolution. To understand Cryptosporidium global population genetic structure, we applied Capture Enrichment Sequencing (CES-Seq) using 74,973 RNA-based 120 nucleotide baits that cover ~92% of the genome of C. parvum. CES-Seq is sensitive and successfully sequenced Cryptosporidium genomic DNA diluted up to 0.005% in human stool DNA. It also resolved mixed strain infections and captured new species of Cryptosporidium directly from clinical/field samples to promote genome-wide phylogenomic analyses and prospective GWAS studies.

The Impact of Measurement Model Misspecification on Coefficient Omega Estimates of Composite Reliability.

Coefficient omega indices are model-based composite reliability estimates that have become increasingly popular. A coefficient omega index estimates how reliably an observed composite score measures a target construct as represented by a factor in a factor-analysis model; as such, the accuracy of omega estimates is likely to depend on correct model specification. The current paper presents a simulation study to investigate the performance of omega-unidimensional (based on the parameters of a one-factor model) and omega-hierarchical (based on a bifactor model) under correct and incorrect model misspecification for high and low reliability composites and different scale lengths. Our results show that coefficient omega estimates are unbiased when calculated from the parameter estimates of a properly specified model. However, omega-unidimensional produced positively biased estimates when the population model was characterized by unmodeled error correlations or multidimensionality, whereas omega-hierarchical was only slightly biased when the population model was either a one-factor model with correlated errors or a higher-order model. These biases were higher when population reliability was lower and increased with scale length. Researchers should carefully evaluate the feasibility of a one-factor model before estimating and reporting omega-unidimensional.

Translation into Spanish and field-testing of a new score for evaluating psoriasis severity: The Simplified Psoriasis Index (SPI). / Traducción al español y ensayos de campo de una nueva escala destinada a la valoración global de la gravedad de la psoriasis: el índice de psoriasis simplificado (SPI).

BACKGROUND: The simplified psoriasis index (SPI) was developed in the United Kingdom to provide a simple summary measure for monitoring changes in psoriasis severity and associated psychosocial impact as well as for obtaining information about past disease behavior and treatment. Two complementary versions of the SPI allow for self-assessment by the patient or professional assessment by a doctor or nurse. Both versions have proven responsive to change, reliable, and interpretable, and to correlate well with assessment tools that are widely used in clinical trials - the Psoriasis Area and Severity Index and the Dermatology Quality of Life Index. The SPI has already been translated into several languages, including French, Brazilian Portuguese, Dutch, Arabic, and Thai. OBJECTIVE: To translate the professional and self-assessment versions of the SPI to Spanish and to field test the translations. METHOD: A medically qualified native Spanish speaker translated both versions of the SPI into Spanish. The Spanish translations were discussed by comparing them to blinded back translations into English undertaken by native English speakers; the Spanish texts were then revised in an iterative process involving the translators, 4 dermatologists, and 20 patients. The patients scored their own experience of psoriasis with the self-assessment version and commented on it. The process involved checking the conceptual accuracy of the translation, language-related differences, and subtle gradations of meaning in a process involving all translators and a panel of both Spanish- and English-speaking dermatologists, including a coauthor of the SPI. RESULTS: The final self-assessment and professional Spanish versions of the SPI are presented in this manuscript. CONCLUSIONS: Castilian Spanish translations of both versions of the SPI are now available for monitoring disease changes in Spanish-speaking patients with psoriasis under routine clinical care.

Traducción al español y ensayos de campo de una nueva escala destinada a la valoración global de la gravedad de la psoriasis: el índice de psoriasis simplificado (SPI) / Translation into Spanish and field-testing of a new score for evaluating psoriasis severity: The Simplified Psoriasis Index (SPI)

Antecedentes: El índice de psoriasis simplificado (SPI) fue desarrollado en el Reino Unido con el fin de proveer un resumen métrico para monitorizar los cambios en la gravedad de la psoriasis (SPI-s) y su impacto social asociado (SPI-p), junto con su comportamiento y tratamiento previo (SPI-i). Existen dos versiones complementarias, una para profesionales de salud, incluidos médicos o enfermeras (proSPI) y otra para la autoevaluación de los pacientes (saSPI). Ambas versiones han demostrado tener una variabilidad al cambio, ser confiables y tener una buena correlación con los instrumentos más utilizados en los estudios clínicos, como el PASI y el DQLI. El SPI estaba ya disponible en versiones adaptadas del francés, portugués (Brasil), holandés, arábigo y tailandés. Objetivo: El objetivo del proyecto actual era producir y probar traducciones del proSPI y saSPI al español. Método: Un médico hispanohablante realizó la primera traducción de ambas versiones al español. Ambas versiones fueron comparadas con sus contratraducciones al inglés de hablantes nativos y luego fueron ajustadas en un proceso repetitivo de múltiples pasos conducidas por traductores, cuatro dermatólogos y veinte pacientes quienes colaboraron con la evaluación del saSPI. Se verificó cuidadosamente la exactitud conceptual al revisar las discrepancias lingüísticas o diferencias sutiles en los significados en un proceso que involucró a todos los traductores y panel incluyendo dermatólogos de habla inglesa como hispana incluyendo a un cocreador del SPI. Resultados: Se presentan en este manuscrito las versiones finales acordadas del SPI en español. Conclusiones: Las versiones del SPI en español (castellano) están ahora disponibles para monitorizar clínicamente a los pacientes con psoriasis (AU)

Background: The simplified psoriasis index (SPI) was developed in the United Kingdom to provide a simple summary measure for monitoring changes in psoriasis severity and associated psychosocial impact as well as for obtaining information about past disease behavior and treatment. Two complementary versions of the SPI allow for self-assessment by the patient or professional assessment by a doctor or nurse. Both versions have proven responsive to change, reliable, and interpretable, and to correlate well with assessment tools that are widely used in clinical trials — the Psoriasis Area and Severity Index and the Dermatology Quality of Life Index. The SPI has already been translated into several languages, including French, Brazilian Portuguese, Dutch, Arabic, and Thai. Objective: To translate the professional and self-assessment versions of the SPI to Spanish and to field test the translations. Method: A medically qualified native Spanish speaker translated both versions of the SPI into Spanish. The Spanish translations were discussed by comparing them to blinded back translations into English undertaken by native English speakers; the Spanish texts were then revised in an iterative process involving the translators, 4 dermatologists, and 20 patients. The patients scored their own experience of psoriasis with the self-assessment version and commented on it. The process involved checking the conceptual accuracy of the translation, language-related differences, and subtle gradations of meaning in a process involving all translators and a panel of both Spanish- and English-speaking dermatologists, including a coauthor of the SPI. Results: The final self-assessment and professional Spanish versions of the SPI are presented in this manuscript. Conclusions: Castilian Spanish translations of both versions of the SPI are now available for monitoring disease changes in Spanish-speaking patients with psoriasis under routine clinical care (AU)

[Translated article] Translation into Spanish and Field-Testing of a New Score for Evaluating Psoriasis Severity: The Simplified Psoriasis Index (SPI) / Traducción al español y ensayos de campo de una nueva escala destinada a la valoración global de la gravedad de la psoriasis: el índice de psoriasis simplificado (SPI)

Background: The simplified psoriasis index (SPI) was developed in the United Kingdom to provide a simple summary measure for monitoring changes in psoriasis severity and associated psychosocial impact as well as for obtaining information about past disease behavior and treatment. Two complementary versions of the SPI allow for self-assessment by the patient or professional assessment by a doctor or nurse. Both versions have proven responsive to change, reliable, and interpretable, and to correlate well with assessment tools that are widely used in clinical trials — the Psoriasis Area and Severity Index and the Dermatology Quality of Life Index. The SPI has already been translated into several languages, including French, Brazilian Portuguese, Dutch, Arabic, and Thai. Objective: To translate the professional and self-assessment versions of the SPI to Spanish and to field test the translations. Method: A medically qualified native Spanish speaker translated both versions of the SPI into Spanish. The Spanish translations were discussed by comparing them to blinded back translations into English undertaken by native English speakers; the Spanish texts were then revised in an iterative process involving the translators, 4 dermatologists, and 20 patients. The patients scored their own experience of psoriasis with the self-assessment version and commented on it. The process involved checking the conceptual accuracy of the translation, language-related differences, and subtle gradations of meaning in a process involving all translators and a panel of both Spanish- and English-speaking dermatologists, including a coauthor of the SPI. Results: The final self-assessment and professional Spanish versions of the SPI are presented in this manuscript. Conclusions: Castilian Spanish translations of both versions of the SPI are now available for monitoring disease changes in Spanish-speaking patients with psoriasis under routine clinical care (AU)

Antecedentes: El índice de psoriasis simplificado (SPI) fue desarrollado en el Reino Unido con el fin de proveer un resumen métrico para monitorizar los cambios en la gravedad de la psoriasis (SPI-s) y su impacto social asociado (SPI-p), junto con su comportamiento y tratamiento previo (SPI-i). Existen dos versiones complementarias, una para profesionales de salud, incluidos médicos o enfermeras (proSPI) y otra para la autoevaluación de los pacientes (saSPI). Ambas versiones han demostrado tener una variabilidad al cambio, ser confiables y tener una buena correlación con los instrumentos más utilizados en los estudios clínicos, como el PASI y el DQLI. El SPI estaba ya disponible en versiones adaptadas del francés, portugués (Brasil), holandés, arábigo y tailandés. Objetivo: El objetivo del proyecto actual era producir y probar traducciones del proSPI y saSPI al español. Método: Un médico hispanohablante realizó la primera traducción de ambas versiones al español. Ambas versiones fueron comparadas con sus contratraducciones al inglés de hablantes nativos y luego fueron ajustadas en un proceso repetitivo de múltiples pasos conducidas por traductores, cuatro dermatólogos y veinte pacientes quienes colaboraron con la evaluación del saSPI. Se verificó cuidadosamente la exactitud conceptual al revisar las discrepancias lingüísticas o diferencias sutiles en los significados en un proceso que involucró a todos los traductores y panel incluyendo dermatólogos de habla inglesa como hispana incluyendo a un cocreador del SPI. Resultados: Se presentan en este manuscrito las versiones finales acordadas del SPI en español. Conclusiones: Las versiones del SPI en español (castellano) están ahora disponibles para monitorizar clínicamente a los pacientes con psoriasis (AU)

Analysis of Cryptosporidium spp. from clinical samples by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

AIM: To purify Cryptosporidium spp. oocysts from clinical stool samples and evaluate using an up-to-date mass spectrometry protocol producing high-quality reference spectra. METHODS AND RESULTS: A refined purification protocol was developed for oocysts from stools, involving salt flotation and potassium bromide density centrifugation. Purified oocysts were prepared for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by formic acid extraction, and the extracts analysed using the Bruker MALDI Biotyper system. Individual spectral markers were identified by their specific mass peaks. Cryptosporidium parvum oocysts (Iowa strain) propagated in vivo, and C. parvum (n = 2) and Cryptosporidium hominis (n = 1) oocysts from clinical stool samples produced distinct spectra that were considered specific to Cryptosporidium spp. with no evidence of contamination. CONCLUSIONS: The production of distinct spectra demonstrated the utility of the purification method for oocysts from clinical stool samples and provided reference spectra. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of MALDI-TOF MS and other mass spectrometry techniques has been limited previously to C. parvum oocysts propagated in vivo. Appropriate purification of oocysts can achieve sufficient biomass, enabling analysis by MALDI-TOF MS and potentially other mass spectrometry platforms, facilitating peptide and protein discovery and identification of biomarkers from a much wider range of Cryptosporidium spp. from natural infections.

Secukinumab efficacy in reducing the severity and the psychosocial impact of moderate-to-severe psoriasis as assessed by the Simplified Psoriasis Index: results from the IPSI-PSO study.

BACKGROUND: The utility of the Simplified Psoriasis Index (SPI), a recently developed multidomain tool for assessing psoriasis, was investigated in a study assessing response to secukinumab. METHODS: In an open-label, multicentre study involving 17 French centres, patients with moderate-to-severe plaque psoriasis received secukinumab 300 mg subcutaneously once weekly from baseline to W4, then every 4 weeks until W48. Dermatologist-scored SPI psoriasis severity (proSPI-s) was compared with Psoriasis Area and Severity Index (PASI). Patient self-assessed severity (saSPI-s) and psychosocial impact (SPI-p) were compared with PASI and Dermatology Life Quality Index (DLQI), respectively. RESULTS: We included 120 patients (69.2% male; mean age 45.9 years; mean duration of psoriasis 21.6 years). Mean baseline scores were as follows: proSPI-s 24.9, saSPI-s 23.5, PASI 23.1, SPI-p 8.2 and DLQI 13.6. Severity scores achieved by 16 weeks (proSPI-s 2.3, saSPI-s 2.2 and PASI 2.2) were maintained to W52. Reductions in mean psychosocial impact scores were maintained to W52 (SPI-p and DLQI, respectively, 2.1 and 1.5 at W16; 1.5 and 1.9 at W52). CONCLUSIONS: Decrease of PASI scores in response to secukinumab was closely correlated with proSPI-s, supporting the latter's suitability for assessing response to therapy. Although the correlation between PASI and saSPI-s was slightly weaker, patients were able to complete a valid assessment of their psoriasis independently, and thus potentially remotely. With the added benefit of psychosocial impact assessment (SPI-p), SPI provides a valid tool enabling patients to assess their own psoriasis, remotely if necessary.

Partially and Fully Noncompensatory Response Models for Dichotomous and Polytomous Items.

This article extends Sympson's partially noncompensatory dichtomous response model to ordered response data, and introduces a set of fully noncompensatory models for dichotomous and polytomous response data. The theoretical properties of the partially and fully noncompensatory response models are contrasted, and a small set of Monte Carlo simulations are presented to evaluate their parameter recovery performance. Results indicate that the respective models fit the data similarly when correctly matched to their respective population generating model. The fully noncompensatory models, however, demonstrated lower sampling variability and smaller degrees of bias than the partially noncompensatory counterparts. Based on the theoretical properties and empirical performance, it is argued that the fully noncompensatory models should be considered in item response theory applications when investigating conjunctive response processes.

Preoperative oral antibiotic bowel preparation in elective resectional colorectal surgery reduces rates of surgical site infections: a single-centre experience with a cost-effectiveness analysis.

INTRODUCTION: Surgical site infections cause considerable postoperative morbidity and mortality. The aim of this study was to determine the effect on surgical site infection rates following introduction of a departmental oral antibiotic bowel preparation protocol. METHODS: A prospective single-centre study was performed for elective colorectal resections between May 2016-April 2018; with a control group with mechanical bowel preparation and treatment group with oral antibiotic bowel preparation (neomycin and metronidazole) and mechanical bowel preparation. The primary outcome of surgical site infection and secondary outcomes of anastomotic leak, length of stay and mortality rate were analysed using Fisher's exact test and independent samples t-tests. A cost-effectiveness analysis was also performed. RESULTS: A total of 311 patients were included; 156 in the mechanical bowel preparation group and 155 in the mechanical bowel preparation plus oral antibiotic bowel preparation group. The study included 180 (57.9%) men and 131 (42.1%) women with a mean age of 68 years. There was a significant reduction in surgical site infection rates (mechanical bowel preparation 16.0% vs mechanical bowel preparation plus oral antibiotic bowel preparation 4.5%; P = 0.001) and mean length of stay (mechanical bowel preparation 10.2 days vs mechanical bowel preparation plus oral antibiotic bowel preparation 8.2 days; P = 0.012). There was also a reduction in anastomotic leak and mortality rates. Subgroup analyses demonstrated significantly reduced surgical site infection rates in laparoscopic resections (P = 0.008). There was an estimated cost saving of £239.13 per patient and £37,065 for our institution over a one-year period. CONCLUSION: Oral antibiotic bowel preparation is a feasible and cost-effective intervention shown to significantly reduce the rates of surgical site infection and length of stay in elective colorectal surgery.

Model Selection of Nested and Non-Nested Item Response Models Using Vuong Tests.

In this paper, we apply Vuong's general approach of model selection to the comparison of nested and non-nested unidimensional and multidimensional item response theory (IRT) models. Vuong's approach of model selection is useful because it allows for formal statistical tests of both nested and non-nested models. However, only the test of non-nested models has been applied in the context of IRT models to date. After summarizing the statistical theory underlying the tests, we investigate the performance of all three distinct Vuong tests in the context of IRT models using simulation studies and real data. In the non-nested case we observed that the tests can reliably distinguish between the graded response model and the generalized partial credit model. In the nested case, we observed that the tests typically perform as well as or sometimes better than the traditional likelihood ratio test. Based on these results, we argue that Vuong's approach provides a useful set of tools for researchers and practitioners to effectively compare competing nested and non-nested IRT models.

[French adaptation of a new score for global assessment of psoriasis severity: The Simplified Psoriasis Index (SPI)]. / Adaptation française d'un nouveau score destiné à l'évaluation globale de la sévérité du psoriasis : l'Indice Simplifié du Psoriasis (Simplified Psoriasis Index, SPI).

OBJECTIVE: Although several scores exist to assess psoriasis severity, most have marked limitations that rule out their use in routine clinical practice. A new score, the Simplified Psoriasis Index (SPI), has recently been developed and validated in adults in Britain for such use. It has separate components for current severity (SPI-s), psychosocial impact (SPI-p) and past history and interventions (SPI-p), and it is suitable for either professional assessment or patient self-assessment. The aim of this work was to produce a validated translation of SPI into French (as spoken in France). METHODS: The index was translated and validated using a strict methodology comprising respectively five and eight phases for the professional (proSPI) and self-administered instruments (saSPI). Translation of the saSPI instrument also involved a cognitive debriefing with five psoriasis patients. RESULTS: Linguistic discrepancies and subtle differences of meaning arising during the process were closely examined. The developer of the instrument ensured conceptual accuracy. A panel of health experts guaranteed that medical terms were correctly translated. Five patients with plaque psoriasis (two female and three male of median age 45 years [range: 31-78]) tested the SPI-p version during cognitive interviews and found the questionnaire clear and easy to understand. CONCLUSION: Validated French translations of both SPI instruments are now available for use in routine clinical practice. Further investigations are currently underway to validate the psychometric properties of the instrument.

Health sequelae of human cryptosporidiosis-a 12-month prospective follow-up study.

To investigate long-term health sequelae of cryptosporidiosis, with especial reference to post-infectious irritable bowel syndrome (PI-IBS). A prospective cohort study was carried out. All patients with laboratory-confirmed, genotyped cryptosporidiosis in Wales, UK, aged between 6 months and 45 years of age, over a 2-year period were contacted. Five hundred and five patients agreed to participate and were asked to complete questionnaires (paper or online) at baseline, 3 and 12 months after diagnosis. The presence/absence of IBS was established using the Rome III criteria for different age groups. Two hundred and five of 505 cases completed questionnaires (40% response rate). At 12 months, over a third of cases reported persistent abdominal pain and diarrhoea, 28% reported joint pain and 26% reported fatigue. At both 3 and 12 months, the proportion reporting fatigue and abdominal pain after Cryptosporidium hominis infection was statistically significantly greater than after C. parvum. Overall, 10% of cases had sufficient symptoms to meet IBS diagnostic criteria. A further 27% met all criteria except 6 months' duration and another 23% had several features of IBS but did not fulfil strict Rome III criteria. There was no significant difference between C. parvum and C. hominis infection with regard to PI-IBS. Post-infectious gastrointestinal dysfunction and fatigue were commonly reported after cryptosporidiosis. Fatigue and abdominal pain were significantly more common after C. hominis compared to C. parvum infection. Around 10% of people had symptoms meriting a formal diagnosis of IBS following cryptosporidiosis. Using age-specific Rome III criteria, children as well as adults were shown to be affected.

Fibrinogen concentrate vs. fresh frozen plasma for the management of coagulopathy during thoraco-abdominal aortic aneurysm surgery: a pilot randomised controlled trial.

Major vascular surgery is frequently associated with significant blood loss and coagulopathy. Existing evidence suggests hypofibrinogenaemia develops earlier than other haemostatic deficiencies during major blood loss. The purpose of this study was to assess whether the use of an infusion of fibrinogen concentrate to prevent and treat hypofibrinogenaemia during surgery resulted in satisfactory haemostasis, removing or reducing the need for blood component transfusion. Twenty patients undergoing elective extent-4 thoraco-abdominal aortic aneurysm repair were randomly allocated to receive either fresh frozen plasma or fibrinogen concentrate to treat hypofibrinogenaemia during surgery. Coagulation was assessed during and after surgery by point-of-care and laboratory testing, respectively, and treatment was guided by pre-defined transfusion triggers. Despite blood losses of up to 11,800 ml in the patients who received the fibrinogen concentrate, none required fresh frozen plasma during surgery, and only two required platelet transfusions. The median (IQR [range]) allogeneic blood component administration during surgery and in the first 24 h postoperatively was 22.5 (14-28 [2-41]) units in patients allocated to fresh frozen plasma vs. 4.5 (3-11[0-17]) in patients allocated to fibrinogen concentrate (p = 0.011). All patients in both groups were assessed by the surgeon to have satisfactory haemostasis at the end of surgery. Mean (SD) postoperative fibrinogen concentrations were similar in patients allocated to fresh frozen plasma and fibrinogen concentrate (1.6 (0.3) g.l-1 vs. 1.6 (0.2) g.l-1 ; p = 0.36) but the mean (SD) international normalised ratio and activated partial thromboplastin time ratio were lower in patients allocated to fresh frozen plasma (1.1 (0.1) vs. 1.8 (0.3); p < 0.0001 and 1.1 (0.2) vs. 1.7 (0.5); p = 0.032, respectively). Fibrinogen concentrate may be used as an alternative to fresh frozen plasma in the treatment of coagulopathy during thoraco-abdominal aortic aneurysm repair.