Browsing by Author "Roberts, I."

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Effect of tranexamic acid on coagulation and fibrinolysis in women with postpartum haemorrhage (WOMAN-ETAC): a single-centre, randomised, double-blind, placebo-controlled trial
(The Wellcome Trust, 2018) Shakur-Still, H.; Roberts, I.; Fawole, B.; Kuti, M.; Olayemi, O. O.; Bello, A.; Huque, S.; Ogunbode, O.; Kotila, T.|; Aimakhu, C.; Okunade, O. A.; Olutogun, T.; Adetayo, C. O.; Dallaku, K.; Mansmann, U.; Hunt, B. J.; Pepple, T.; Balogun, E.
Background: Postpartum haemorrhage (PPH) is a leading cause of maternal death. The WOMAN trial showed that tranexamic acid (TXA) reduces death due to bleeding in women with PPH. We evaluated the effect of TXA on fibrinolysis and coagulation in a sample of WOMAN trial participants. Methods: Adult women with a clinical diagnosis of PPH were randomised to receive 1 g TXA or matching placebo in the WOMAN trial. Participants in the WOMAN trial at University College Hospital (Ibadan, Nigeria) also had venous blood taken just before administration of the first dose of trial treatment and again 30 (±15) min after the first dose (the ETAC study). We aimed to determine the effects of TXA on fibrinolysis (D-dimer and rotational thromboelastometry maximum clot lysis (ML)) and coagulation (international normalized ratio and clot amplitude at 5 min). We compared outcomes in women receiving TXA and placebo using linear regression, adjusting for baseline measurements. Results: Women (n=167) were randomised to receive TXA (n=83) or matching placebo (n=84). Due to missing data, seven women were excluded from analysis. The mean (SD) D-dimer concentration was 7.1 (7.0) mg/l in TXA-treated women and 9.6 (8.6) mg/l in placebo-treated women (p=0.09). After adjusting for baseline, the D-dimer concentration was 2.16 mg/l lower in TXA-treated women (-2.16, 95% CI -4.31 to 0.00, p=0.05). There was no significant difference in ML between TXA- and placebo-treated women (12.3% (18.4) and 10.7% (12.6), respectively; p=0.52) and no significant difference after adjusting for baseline ML (1.02, 95% CI -3.72 to 5.77, p=0.67). There were no significant effects of TXA on any other parameters. Conclusion: TXA treatment was associated with reduced D-dimer levels but had no apparent effects on thromboelastometry parameters or coagulation tests.
Effect of tranexamic acid on coagulation and fibrinolysis in women with postpartum haemorrhage (WOMAN-ETAC): protocol and statistical analysis plan for a randomized controlled trial
(Wellcome Trust., 2016) Shakur, H.; Fawole, B.; Kuti, M.; Olayemi, O.; Bello, A.; Ogunbode, O.; Kotila, T.; Aimakhu, S. H.; Gregg, M.; Roberts, I.
Background: Postpartum haemorrhage (PPH) is a leading cause of maternal death. Tranexamic acid has the potential to reduce bleeding and a large randomized controlled trial of its effect on maternal health outcomes in women with PPH (The WOMAN trial) is ongoing. We will examine the effect oftranexamic acid on fibrinolysis and coagulation in a subset of WOMAN trial participants. Methods: Adult women with clinically diagnosed primary PPH after vaginal or caesarean delivery are eligible for inclusion in the WOMAN trial. In a sub-group of trial participants, blood samples will be collected at baseline and 30 minutes after the first dose of tranexamic acid or matching placebo. Our primary objective is to evaluate the effect of tranexamic acid on fibrinolysis. Fibrinolysis will be assessed by measuring D-dimers and by rotational thromboelastometry (ROTEM). Secondary outcomes are international normalized ratio (INR), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, haemoglobin and platelets. We aim to include about 180 women from the University College Hospital, Ibadan in Nigeria. Discussion: This sub-study of WOMAN trial participants should provide information on the mechanism of action of tranexamic acid in women with postpartum haemorrhage. We present the trial protocol and statistical analysis plan. The trial protocol was registered prior to the start of patient recruitment. The statistical analysis plan was completed before un-blinding.
Haematological and fibrinolytic status of Nigerian women with post-partum haemorrhage
(BioMed Central(BMC), 2018) Roberts, I.; Shakur, H.; Fawole, B.; Kuti, M.; Olayemi, O.; Bello, A.; Ogunbode, O.; Kotila, T..; Aimakhu, C. O.; Olutogun, T.; Hunt, B. J.; Huque, S
Background: Early treatment with tranexamic acid reduces deaths due to bleeding after post-partum haemorrhage. We report the prevalence of haematological, coagulation and fibrinolytic abnormalities in Nigerian women with postpartum haemorrhage. Methods: We performed a secondary analysis of the WOMAN trial to assess laboratory data and rotational thromboelastometry (ROTEM) parameters in 167 women with postpartum haemorrhage treated at University College Hospital, Ibadan, Nigeria. We defined hyper-fibrinolysis as EXTEM maximum lysis (ML) > 15% on ROTEM. We defined coagulopathy as EXTEM clot amplitude at 5 min (A5) < 40 mm or prothrombin ratio > 1.5. Results: Among the study cohort, 53 (40%) women had severe anaemia (haemoglobin< 70 g/L) and 17 (13%) women had severe thrombocytopenia (platelet count < 50 × 109/L). Thirty-five women (23%) had ROTEM evidence of hyper-fibrinolysis. Based on prothrombin ratio criteria, 16 (12%) had coagulopathy. Based on EXTEM A5 criteria, 49 (34%) had coagulopathy. Conclusion: Our findings suggest that, based on a convenience sample of women from a large teaching hospital in Nigeria, hyper-fibrinolysis may commonly occur in postpartum haemorrhage. Further mechanistic studies are needed to examine hyper-fibrinolysis associated with postpartum haemorrhage. Findings from such studies may optimize treatment approaches for postpartum haemorrhage.
Tranexamic acid for acute gastrointestinal bleeding (the HALT-IT trial): statistical analysis plan for an international, randomised, double-blind, placebo-controlled trial
(Springer Nature, 2019) Brenner, A.; Afolabi, A.; Ahmad, S. M.; Arribas, M.; Chaudhri, R.; Coats, T.; Cuzick, J.; Gilmore, I.; Hawkey, C.; Jairath, V.; Javaid, K.; Kayani, A.; Mutti, M.; Nadeem, M. A.; Shakur-Still, H.; Stanworth, S.; Veitch, A.; Roberts, I.
Background: Acute gastrointestinal (GI) bleeding is an important cause of mortality worldwide. Bleeding can occur from the upper or lower GI tract, with upper GI bleeding accounting for most cases. The main causes include peptic ulcer/erosive mucosal disease, oesophageal varices and malignancy. The case fatality rate is around 10% for upper GI bleeding and 3% for lower GI bleeding. Rebleeding affects 5–40% of patients and is associated with a four-fold increased risk of death. Tranexamic acid (TXA) decreases bleeding and the need for blood transfusion in surgery and reduces death due to bleeding in patients with trauma and postpartum haemorrhage. It reduces bleeding by inhibiting the breakdown of fibrin clots by plasmin. Due to the methodological weaknesses and small size of the existing trials, the effectiveness and safety of TXA in GI bleeding is uncertain. The Haemorrhage ALleviation with Tranexamic acid – Intestinal system (HALT-IT) trial aims to provide reliable evidence about the effects of TXA in acute upper and lower GI bleeding. Methods: The HALT-IT trial is an international, randomised, double-blind, placebo-controlled trial of tranexamic acid in 12,000 adults (increased from 8000) with acute upper or lower GI bleeding. Eligible patients are randomly allocated to receive TXA (1-g loading dose followed by 3-g maintenance dose over 24 h) or matching placebo. The main analysis will compare those randomised to TXA with those randomised to placebo on an intention-to-treat basis, presenting the results as effect estimates (relative risks) and confidence intervals. The primary outcome is death due to bleeding within 5 days of randomisation and secondary outcomes are: rebleeding; all-cause and cause-specific mortality; thromboembolic events; complications; endoscopic, radiological and surgical interventions; blood transfusion requirements; disability (defined by a measure of patient’s self-care capacity); and number of days spent in intensive care or high-dependency units. Subgroup analyses for the primary outcome will consider time to treatment, location of bleeding, cause of bleed and clinical Rockall score. Discussion: We present the statistical analysis of the HALT-IT trial. This plan was published before the treatment allocation was unblinded.