Thrombotic thrombocytopenic purpura (TTP) is a rare, potentially fatal thrombotic microangiopathy caused by severe ADAMTS13 deficiency. Prompt treatment improves survival; however, reference standard ELISA and FRETS-VWF73 ADAMTS13 activity assays have long turnaround times that necessitate empiric treatment of many patients who ultimately are found not to have TTP. Rapid assays with analytical turnaround times within one hour have recently become available. We conducted a systematic review and meta-analysis of the performance characteristics of rapid assays relative to reference standard assays for ADAMTS13 activity for patients with suspected or confirmed TTP. Nineteen studies representing three rapid ADAMTS13 assays and 4,207 patient samples were included. The HemosIL AcuStar CLIA demonstrated high sensitivity (0.98, 95% CI 0.94 - 1.00), specificity (0.99, 0.97 - 1.00), and positive (0.96, 0.90 - 0.98) and negative predictive value (0.99, 0.99 - 1.00). The Technofluor FRET and Technoscreen assays had sensitivity of 0.93 (0.86 - 0.96) and 0.98 (0.42 - 1.00), specificity of 0.98 (0.95 - 0.99) and 0.87 (0.76 - 0.94), PPV of 0.97 (0.85 - 1.00) and 0.71 (0.59 - 0.80), and NPV of 0.96 (0.93 - 0.98) and 0.99 (0.72 - 1.00), respectively. The proportion of discrepant results (relative to reference standard assays) was 0.04 (0.03 - 0.05) for HemosIL AcuStar, 0.04 (0.02 - 0.06) for Technofluor FRET, and 0.11 (0.07 - 0.16) for the Technoscreen assay. With rapid turnaround time and high sensitivity, the HemosIL AcuStar CLIA appears able to reliably avert empiric plasma exchange, corticosteroids, and caplacizumab in patients without TTP.

Globally, an estimated 300 million individuals have sickle cell trait (SCT), the carrier state for sickle cell disease (SCD). Although SCD is associated with increased morbidity and shortened life span, SCT has a life span comparable with that of the general population. However, "sickle cell crisis" has been used as a cause of death for decedents with SCT in reports of exertion-related death in athletes, military personnel, and individuals in police custody. To appraise this practice, the American Society of Hematology convened an expert panel of hematologists and forensic pathologists to conduct a systematic review of the literature relating to the occurrence of sickle cell pain crises and exertion-related mortality in people with SCT. Multiple bibliographic databases were searched with controlled vocabulary and keywords related to "sickle cell trait," "vaso-occlusive pain," and "death," yielding 18 of 1474 citations. Independent pairs of reviewers selected studies and extracted data. We found no studies comparing uncomplicated acute pain crises in individuals with SCT and SCD. Additionally, no study was identified to support the occurrence of acute vaso-occlusive pain crises in individuals with SCT. Furthermore, this systematic review did not identify any evidence to support an association between SCT and sudden unexplained death in the absence of exertion-related rhabdomyolysis. We conclude that there are no data to support the diagnosis of acute vaso-occlusive sickle cell crisis as a cause of death in SCT, nor does the available evidence support the use of SCT as a cause of exertion-related death without rhabdomyolysis.

Desmopressin (1-desamino-8-d-arginine vasopressin [DDAVP]) can be used to prevent or stop bleeding. However, large interindividual variability is observed in DDAVP response and determinants are largely unknown. In this systematic review and meta-analysis, we aimed to identify the response to DDAVP and the factors that determine DDAVP response in patients. We included studies with patients with any bleeding disorder receiving DDAVP. First and second screening round and risk of bias assessment were performed by independent reviewers. The main outcome was proportion of patients with complete (factor level >50 U/dL) or partial (30-50 U/dL) response to DDAVP. Determinants of response including disease type, age, sex, von Willebrand factor (VWF) and factor VIII (FVIII) mutations, and baseline factor levels were investigated. In total, 591 articles were found and 103 were included. Of these, 71 articles (1772 patients) were suitable for the study's definition of response. Meta-analysis showed a pooled response proportion of 0.71 (0.64; 0.78) and a significant difference in response between disease subtypes. For hemophilia A, baseline FVIII activity (FVIII:C) was a borderline significant determinant of response. In patients with von Willebrand disease (VWD) type 1, VWF antigen (VWF:Ag), VWF activity, and FVIII:C were significant determinants. A large variation in response was observed for specific mutations in VWF and FVIII. Response to DDAVP varied between disease subtypes and was largely determined by the baseline levels of FVIII:C for hemophilia A and VWF:Ag for VWD. Our findings highlight the significant differences in response and emphasize the need for a standardized response definition and further research into response mechanisms.

The benefit associated with the incorporation of vincristine-corticosteroid pulses in maintenance therapy for pediatric acute lymphoblastic leukemia (ALL) is unclear, particularly in the context of modern intensive therapy. This systematic review and meta-analysis examined the impact of reducing the frequency of vincristine-steroid pulses during maintenance for pediatric patients newly diagnosed with B-cell ALL. Two authors reviewed all eligible studies identified through a comprehensive search, extracted data from 25 publications (12 513 patients), and assessed the risk of bias. We created historical and contemporary subgroups; the latter included trials providing both a version of Protocol III from the early Berlin-Frankfurt-Munster trials and eliminating routine prophylactic cranial radiation. Meta-analysis of event-free survival data suggested no benefit between more frequent or less frequent pulses in contemporary trials (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.85-1.09), which differed significantly from historical trials (HR, 0.79; 95% CI, 0.68-0.91; P = .04). We found no significant impact of reduced pulse frequency on overall survival or relapse risk. There was however increased odds of grade 3+ nonhepatic toxicity in the high-pulse frequency group (odds ratio, 1.31; 95% CI, 1.12-1.52). This systematic review suggests that the previous benefit conferred by frequent pulses of vincristine-steroids in maintenance therapy for pediatric B-cell ALL in historical trials no longer applies in contemporary trials but is associated with toxicity. These results will help guide the development of the next phase of clinical trials in the field of pediatric ALL and question the continued use of pulses in maintenance among patients not in clinical trials, particularly those experiencing toxicity.

Intracranial hemorrhage (ICH) is a severe complication that is relatively common among patients with hemophilia. This systematic review aimed to obtain more precise estimates of ICH incidence and mortality in hemophilia, which may be important for patients, caregivers, researchers, and health policy makers. PubMed and EMBASE were systematically searched using terms related to "hemophilia" and "intracranial hemorrhage" or "mortality." Studies that allowed calculation of ICH incidence or mortality rates in a hemophilia population ≥50 patients were included. We summarized evidence on ICH incidence and calculated pooled ICH incidence and mortality in 3 age groups: persons of all ages with hemophilia, children and young adults younger than age 25 years with hemophilia, and neonates with hemophilia. Incidence and mortality were pooled with a Poisson-Normal model or a Binomial-Normal model. We included 45 studies that represented 54 470 patients, 809 151 person-years, and 5326 live births of patients with hemophilia. In persons of all ages, the pooled ICH incidence and mortality rates were 2.3 (95% confidence interval [CI], 1.2-4.8) and 0.8 (95% CI 0.5-1.2) per 1000 person-years, respectively. In children and young adults, the pooled ICH incidence and mortality rates were 7.4 (95% CI, 4.9-11.1) and 0.5 (95% CI, 0.3-0.9) per 1000 person-years, respectively. In neonates, the pooled cumulative ICH incidence was 2.1% (95% CI, 1.5-2.8) per 100 live births. ICH was classified as spontaneous in 35% to 58% of cases. Our findings suggest that ICH is an important problem in hemophilia that occurs among all ages, requiring adequate preventive strategies.

Outcomes for patients with hematologic malignancy infected with COVID-19 have not been aggregated. The objective of this study was to perform a systematic review and meta-analysis to estimate the risk of death and other important outcomes for these patients. We searched PubMed and EMBASE up to 20 August 2020 to identify reports of patients with hematologic malignancy and COVID-19. The primary outcome was a pooled mortality estimate, considering all patients and only hospitalized patients. Secondary outcomes included risk of intensive care unit admission and ventilation in hospitalized patients. Subgroup analyses included mortality stratified by age, treatment status, and malignancy subtype. Pooled prevalence, risk ratios (RRs), and 95% confidence intervals (CIs) were calculated using a random-effects model. Thirty-four adult and 5 pediatric studies (3377 patients) from Asia, Europe, and North America were included (14 of 34 adult studies included only hospitalized patients). Risk of death among adult patients was 34% (95% CI, 28-39; N = 3240) in this sample of predominantly hospitalized patients. Patients aged ≥60 years had a significantly higher risk of death than patients <60 years (RR, 1.82; 95% CI, 1.45-2.27; N = 1169). The risk of death in pediatric patients was 4% (95% CI, 1-9; N = 102). RR of death comparing patients with recent systemic anticancer therapy to no treatment was 1.17 (95% CI, 0.83-1.64; N = 736). Adult patients with hematologic malignancy and COVID-19, especially hospitalized patients, have a high risk of dying. Patients ≥60 years have significantly higher mortality; pediatric patients appear to be relatively spared. Recent cancer treatment does not appear to significantly increase the risk of death.

Treatment of splanchnic vein thrombosis (SVT) is challenging, and evidence to guide therapeutic decisions remains scarce. The objective of this systematic review and meta-analysis was to determine the efficacy and safety of anticoagulant therapy for SVT. MEDLINE, EMBASE, and clinicaltrials.gov were searched from inception through December 2019, without language restrictions, to include observational studies and randomized controlled trials reporting radiological or clinical outcomes in patients with SVT. Pooled proportions and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated in a random-effects model. Of 4312 records identified by the search, 97 studies including 7969 patients were analyzed. In patients receiving anticoagulation, the rates of SVT recanalization, SVT progression, recurrent venous thromboembolism (VTE), major bleeding, and overall mortality were 58% (95% CI, 51-64), 5% (95% CI, 3-7), 11% (95% CI, 8-15), 9% (95% CI, 7-12), and 11% (95% CI, 9-14), respectively. The corresponding values in patients without anticoagulation were 22% (95% CI, 15-31), 15% (95% CI, 8-27), 14% (95% CI, 9-21), 16% (95% CI, 13-20), and 25% (95% CI, 20-31). Compared with no treatment, anticoagulant therapy obtained higher recanalization (RR, 2.39; 95% CI, 1.66-3.44) and lower thrombosis progression (RR, 0.24; 95% CI, 0.13-0.42), major bleeding (RR, 0.73; 95% CI, 0.58-0.92), and overall mortality (RR, 0.45; 95% CI, 0.33-0.60). These results demonstrate that anticoagulant therapy improves SVT recanalization and reduces the risk of thrombosis progression without increasing major bleeding. The incidence of recurrent VTE remained substantial in patients receiving anticoagulation, as well. Effects were consistent across the different subgroups of patients. This trial was registered on the PROPERO database at (https://www.crd.york.ac.uk/prospero//display_record.php?ID=CRD42019127870) as #CRD42019127870.

Direct oral anticoagulants (DOACs) are an emerging treatment option for patients with cancer and acute venous thromboembolism (VTE), but studies have reported inconsistent results. This systematic review and meta-analysis compared the efficacy and safety of DOACs and low-molecular-weight heparins (LMWHs) in these patients. MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and conference proceedings were searched to identify relevant randomized controlled trials. Additional data were obtained from the original authors to homogenize definitions for all study outcomes. The primary efficacy and safety outcomes were recurrent VTE and major bleeding, respectively. Other outcomes included the composite of recurrent VTE and major bleeding, clinically relevant nonmajor bleeding (CRNMB), and all-cause mortality. Summary relative risks (RRs) were calculated in a random effects meta-analysis. In the primary analysis comprising 2607 patients, the risk of recurrent VTE was nonsignificantly lower with DOACs than with LMWHs (RR, 0.68; 95% CI, 0.39-1.17). Conversely, the risks of major bleeding (RR, 1.36; 95% CI, 0.55-3.35) and CRNMB (RR, 1.63; 95% CI, 0.73-3.64) were nonsignificantly higher. The risk of the composite of recurrent VTE or major bleeding was nonsignificantly lower with DOACs than with LMWHs (RR, 0.86; 95% CI, 0.60-1.23). Mortality was comparable in both groups (RR, 0.96; 95% CI, 0.68-1.36). Findings were consistent during the on-treatment period and in those with incidental VTE. In conclusion, DOACs are an effective treatment option for patients with cancer and acute VTE, although caution is needed in patients at high risk of bleeding.

There may be many predictors of venous thromboembolism (VTE) and bleeding in hospitalized medical patients, but until now, systematic reviews and assessments of the certainty of the evidence have not been published. We conducted a systematic review to identify prognostic factors for VTE and bleeding in hospitalized medical patients and searched Medline and EMBASE from inception through May 2018. We considered studies that identified potential prognostic factors for VTE and bleeding in hospitalized adult medical patients. Reviewers extracted data in duplicate and independently and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. Of 69 410 citations, we included 17 studies in our analysis: 14 that reported on VTE, and 3 that reported on bleeding. For VTE, moderate-certainty evidence showed a probable association with older age; elevated C-reactive protein (CRP), D-dimer, and fibrinogen levels; tachycardia; thrombocytosis; leukocytosis; fever; leg edema; lower Barthel Index (BI) score; immobility; paresis; previous history of VTE; thrombophilia; malignancy; critical illness; and infections. For bleeding, moderate-certainty evidence showed a probable association with older age, sex, anemia, obesity, low hemoglobin, gastroduodenal ulcers, rehospitalization, critical illness, thrombocytopenia, blood dyscrasias, hepatic disease, renal failure, antithrombotic medication, and presence of a central venous catheter. Elevated CRP, a lower BI, a history of malignancy, and elevated heart rate are not included in most VTE risk assessment models. This study informs risk prediction in the management of hospitalized medical patients for VTE and bleeding; it also informs guidelines for VTE prevention and future research.