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Expected individual benefit of prophylactic platelet transfusions in hemato-oncology patients based on bleeding risks
Cornelissen LL, Caram-Deelder C, Fustolo-Gunnink SF, Groenwold RHH, Stanworth SJ, Zwaginga JJ, van der Bom JG
Transfusion. 2021
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Editor's Choice
Abstract
BACKGROUND Prophylactic platelet transfusions prevent bleeding in hemato-oncology patients, but it is unclear how any benefit varies between patients. Our aim was to assess if patients with different baseline risks for bleeding benefit differently from a prophylactic platelet transfusion strategy. STUDY DESIGN AND METHODS Using the data from the randomized controlled TOPPS trial (Trial of Platelet Prophylaxis), we developed a prediction model for World Health Organization grades 2, 3, and 4 bleeding risk (defined as at least one bleeding episode in a 30 days period) and grouped patients in four risk-quartiles based on this predicted baseline risk. Predictors in the model were baseline platelet count, age, diagnosis, disease modifying treatment, disease status, previous stem cell transplantation, and the randomization arm. RESULTS The model had a c-statistic of 0.58 (95% confidence interval [CI] 0.54-0.64). There was little variation in predicted risks (quartiles 46%, 47%, and 51%), but prophylactic platelet transfusions gave a risk reduction in all risk quartiles. The absolute risk difference (ARD) was 3.4% (CI -12.2 to 18.9) in the lowest risk quartile (quartile 1), 7.4% (95% CI -8.4 to 23.3) in quartile 2, 6.8% (95% CI -9.1 to 22.9) in quartile 3, and 12.8% (CI -3.1 to 28.7) in the highest risk quartile (quartile 4). CONCLUSION In our study, generally accepted bleeding risk predictors had limited predictive power (expressed by the low c-statistic), and, given the wide confidence intervals of predicted ARD, could not aid in identifying subgroups of patients who might benefit more (or less) from prophylactic platelet transfusion.
PICO Summary
Population
Haemato-oncology patients enrolled in the TOPPS trial (n= 600).
Intervention
Platelet transfusions based on a threshold of 10 × 10 9/L (Prophylactic arm, n= 299).
Comparison
Platelet transfusions in case of active bleeding (Therapeutic arm, n= 301).
Outcome
47% of patients (279) developed at least one WHO grade 2, 3, or 4 bleeding during 30-day follow-up. The model had a c-statistic of 0.58. There was little variation in predicted risks (quartiles 46%, 47%, and 51%), but prophylactic platelet transfusions gave a risk reduction in all risk quartiles. The absolute risk difference was 3.4% in the lowest risk quartile (quartile 1), 7.4% in quartile 2, 6.8% in quartile 3, and 12.8% in the highest risk quartile (quartile 4).
2.
Preterm neonates benefit from low prophylactic platelet transfusion threshold despite varying risk of bleeding or death
Fustolo-Gunnink SF, Fijnvandraat K, van Klaveren D, Stanworth S, Curley AE, Onland W, Steyerberg EW, de Kort E, d'Haens E, Hulzebos C, et al
Blood. 2019
Abstract
The Platelets for Neonatal Thrombocytopenia (PlaNeT-2) trial reported an unexpected overall benefit of a prophylactic platelet transfusion threshold of 25x109/L compared to 50x109/L for major bleeding and/or mortality in preterm neonates (7% absolute risk reduction). However, some neonates in the trial may have experienced little benefit or even harm from the 25x109/L threshold. We aimed to assess this heterogeneity of treatment effect in the PlaNet-2 trial, in order to investigate whether all preterm neonates benefit from the low threshold. We developed a multivariable logistic regression model in the PlaNet-2 data to predict baseline risk of major bleeding and/or mortality for all 653 neonates. We then ranked the neonates based on their predicted baseline risk and categorized them into four risk quartiles. Within these quartiles we assessed absolute risk difference between the 50x109/L and 25x109/L threshold group. A total of 146 neonates died or developed major bleeding. The internally validated C-statistic of the model was 0.63 (95% confidence interval 0.58 - 0.68). The 25x109/L threshold was associated with absolute risk reduction in all risk groups, varying from 4.9% in the lowest to 12.3% in the highest risk group. These results suggest that a 25x109/L prophylactic platelet count threshold can be adopted in all preterm neonates, irrespective of predicted baseline outcome risk. Future studies are needed to improve the predictive accuracy of the baseline risk model. Current Controlled Trials number ISRCTN87736839.
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Randomized Trial of Platelet-Transfusion Thresholds in Neonates
Curley A, Stanworth SJ, Willoughby K, Fustolo-Gunnink SF, Venkatesh V, Hudson C, Deary A, Hodge R, Hopkins V, Lopez Santamaria B, et al
The New England Journal of Medicine. 2019;380:242-251
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Editor's Choice
Abstract
BACKGROUND Platelet transfusions are commonly used to prevent bleeding in preterm infants with thrombocytopenia. Data are lacking to provide guidance regarding thresholds for prophylactic platelet transfusions in preterm neonates with severe thrombocytopenia. METHODS In this multicenter trial, we randomly assigned infants born at less than 34 weeks of gestation in whom severe thrombocytopenia developed to receive a platelet transfusion at platelet-count thresholds of 50,000 per cubic millimeter (high-threshold group) or 25,000 per cubic millimeter (low-threshold group). Bleeding was documented prospectively with the use of a validated bleeding-assessment tool. The primary outcome was death or new major bleeding within 28 days after randomization. RESULTS A total of 660 infants (median birth weight, 740 g; and median gestational age, 26.6 weeks) underwent randomization. In the high-threshold group, 90% of the infants (296 of 328 infants) received at least one platelet transfusion, as compared with 53% (177 of 331 infants) in the low-threshold group. A new major bleeding episode or death occurred in 26% of the infants (85 of 324) in the high-threshold group and in 19% (61 of 329) in the low-threshold group (odds ratio, 1.57; 95% confidence interval [CI], 1.06 to 2.32; P=0.02). There was no significant difference between the groups with respect to rates of serious adverse events (25% in the high-threshold group and 22% in the low-threshold group; odds ratio, 1.14; 95% CI, 0.78 to 1.67). CONCLUSIONS Among preterm infants with severe thrombocytopenia, those randomly assigned to receive platelet transfusions at a platelet-count threshold of less than 50,000 per cubic millimeter had a significantly higher rate of death or major bleeding within 28 days after randomization than those in the group that received less than 25,000 per cubic millimeter. (Funded by the National Health Service Blood and Transplant Research and Development Committee and others; Current Controlled Trials number, ISRCTN87736839 .).
PICO Summary
Population
Infants born at less than 34 weeks of gestation in whom severe thrombocytopenia developed, from centres in Ireland, The Netherlands and UK (n= 660).
Intervention
platelet-count thresholds of 50,000 per cubic millimeter (high-threshold group, n= 328).
Comparison
25,000 per cubic millimeter (low-threshold group, n= 331).
Outcome
In the high-threshold group, 90% of the infants (296 of 328 infants) received at least one platelet transfusion, as compared with 53% (177 of 331 infants) in the low-threshold group. A new major bleeding episode or death occurred in 26% of the infants (85 of 324) in the high-threshold group and in 19% (61 of 329) in the low-threshold group (odds ratio, 1.57; 95% confidence interval [CI], 1.06 to 2.32). There was no significant difference between the groups with respect to rates of serious adverse events (25% in the high-threshold group and 22% in the low-threshold group; odds ratio, 1.14; 95% CI, 0.78 to 1.67).