Restrictive versus liberal red blood cell transfusion strategies for people with haematological malignancies treated with intensive chemotherapy or radiotherapy, or both, with or without haematopoietic stem cell support

BACKGROUND

An estimated one-quarter to one-half of people diagnosed with haematological malignancies experience anaemia. There are different strategies for red blood cell (RBC) transfusions to treat anaemia. A restrictive transfusion strategy permits a lower haemoglobin (Hb) level whereas a liberal transfusion strategy aims to maintain a higher Hb. The most effective and safest strategy is unknown.

OBJECTIVES

To determine the efficacy and safety of restrictive versus liberal RBC transfusion strategies for people diagnosed with haematological malignancies treated with intensive chemotherapy or radiotherapy, or both, with or without a haematopoietic stem cell transplant (HSCT).

SEARCH METHODS

We searched for randomised controlled trials (RCTs) and non-randomised studies (NRS) in MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1982), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2023, Issue 2), and eight other databases (including three trial registries) to 21 March 2023. We also searched grey literature and contacted experts in transfusion for additional trials. There were no language, date or publication status restrictions.

SELECTION CRITERIA

We included RCTs and prospective NRS that evaluated restrictive versus liberal RBC transfusion strategies in children or adults with malignant haematological disorders receiving intensive chemotherapy or radiotherapy, or both, with or without HSCT.

DATA COLLECTION AND ANALYSIS

Two authors independently screened references, full-text reports of potentially relevant studies, extracted data from the studies, and assessed the risk of bias. Any disagreement was discussed and resolved with a third review author. Dichotomous outcomes were presented as a risk ratio (RR) with a 95% confidence interval (CI). Narrative syntheses were used for heterogeneous outcome measures. Review Manager Web was used to meta-analyse the data. Main outcomes of interest included: all-cause mortality at 31 to 100 days, quality of life, number of participants with any bleeding, number of participants with clinically significant bleeding, serious infections, length of hospital admission (days) and hospital readmission at 0 to 3 months. The certainty of the evidence was assessed using GRADE.

MAIN RESULTS

Nine studies met eligibility; eight RCTs and one NRS. Six hundred and forty-four participants were included from six completed RCTs (n = 560) and one completed NRS (n = 84), with two ongoing RCTs consisting of 294 participants (260 adult and 34 paediatric) pending inclusion. Only one completed RCT included children receiving HSCT (n = 6); the other five RCTs only included adults: 239 with acute leukaemia receiving chemotherapy and 315 receiving HSCT (166 allogeneic and 149 autologous). The transfusion threshold ranged from 70 g/L to 80 g/L for restrictive and from 80 g/L to 120 g/L for liberal strategies. Effects were reported in the summary of findings tables only for the trials that included adults to reduce indirectness due to the limited evidence contributed by the prematurely terminated paediatric trial. Evidence from RCTs Overall, there may be little to no difference in the number of participants who die within 31 to 100 days using a restrictive compared to a liberal transfusion strategy, but the evidence is very uncertain (three studies; 451 participants; RR 1.00, 95% CI 0.27 to 3.70, P=0.99; very low-certainty evidence). There may be little to no difference in quality of life at 0 to 3 months using a restrictive compared to a liberal transfusion strategy, but the evidence is very uncertain (three studies; 431 participants; analysis unable to be completed due to heterogeneity; very low-certainty evidence). There may be little to no difference in the number of participants who suffer from any bleeding at 0 to 3 months using a restrictive compared to a liberal transfusion strategy (three studies; 448 participants; RR 0.91, 95% CI 0.78 to 1.06, P = 0.22; low-certainty evidence). There may be little to no difference in the number of participants who suffer from clinically significant bleeding at 0 to 3 months using a restrictive compared to a liberal transfusion strategy (four studies; 511 participants; RR: 0.94, 95% CI 0.74 to 1.19, P = 0.60; low-certainty evidence). There may be little to no difference in the number of participants who experience serious infections at 0 to 3 months using a restrictive compared to a liberal transfusion strategy (three studies, 451 participants; RR: 1.20, 95% CI 0.93 to 1.55, P = 0.17; low-certainty evidence). A restrictive transfusion strategy likely results in little to no difference in the length of hospital admission at 0 to 3 months compared to a liberal strategy (two studies; 388 participants; analysis unable to be completed due to heterogeneity in reporting; moderate-certainty evidence). There may be little to no difference between hospital readmission using a restrictive transfusion strategy compared to a liberal transfusion strategy (one study, 299 participants; RR: 0.89, 95% CI 0.52 to 1.50; P = 0.65; low-certainty evidence). Evidence from NRS The evidence is very uncertain whether a restrictive RBC transfusion strategy: reduces the risk of death within 100 days (one study, 84 participants, restrictive 1 death; liberal 1 death; very low-certainty evidence); or decreases the risk of clinically significant bleeding (one study, 84 participants, restrictive 3; liberal 8; very low-certainty evidence). No NRS reported on the other eligible outcomes.

AUTHORS' CONCLUSIONS

Findings from this review were based on seven studies and 644 participants. Definite conclusions are challenging given the relatively few included studies, low number of included participants, heterogeneity of intervention and outcome reporting, and overall certainty of evidence. To increase the certainty of the true effect of a restrictive RBC transfusion strategy on clinical outcomes, there is a need for rigorously designed and executed studies. The evidence is largely based on two populations: adults with acute leukaemia receiving intensive chemotherapy and adults with haematologic malignancy requiring HSCT. Despite the addition of 405 participants from three RCTs to the previous review's results, there is still insufficient evidence to answer this review's primary outcome. If we assume a mortality rate of 3% within 100 days, we would need a total of 1492 participants to have an 80% chance of detecting, at a 5% level of significance, an increase in all-cause mortality from 3% to 6%. Further RCTs are needed overall, particularly in children.

Pharmacological interventions for the prevention of bleeding in people undergoing elective hip or knee surgery: a systematic review and network meta-analysis

BACKGROUND

Hip and knee replacement surgery is a well-established means of improving quality of life, but is associated with a significant risk of bleeding. One-third of people are estimated to be anaemic before hip or knee replacement surgery; coupled with the blood lost during surgery, up to 90% of individuals are anaemic postoperatively. As a result, people undergoing orthopaedic surgery receive 3.9% of all packed red blood cell transfusions in the UK. Bleeding and the need for allogeneic blood transfusions has been shown to increase the risk of surgical site infection and mortality, and is associated with an increased duration of hospital stay and costs associated with surgery. Reducing blood loss during surgery may reduce the risk of allogeneic blood transfusion, reduce costs and improve outcomes following surgery. Several pharmacological interventions are available and currently employed as part of routine clinical care.

OBJECTIVES

To determine the relative efficacy of pharmacological interventions for preventing blood loss in elective primary or revision hip or knee replacement, and to identify optimal administration of interventions regarding timing, dose and route, using network meta-analysis (NMA) methodology.

SEARCH METHODS

We searched the following databases for randomised controlled trials (RCTs) and systematic reviews, from inception to 18 October 2022: CENTRAL (the Cochrane Library), MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCOhost), Transfusion Evidence Library (Evidentia), ClinicalTrials.gov and WHO International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

We included RCTs of people undergoing elective hip or knee surgery only. We excluded non-elective or emergency procedures, and studies published since 2010 that had not been prospectively registered (Cochrane Injuries policy). There were no restrictions on gender, ethnicity or age (adults only). We excluded studies that used standard of care as the comparator. Eligible interventions included: antifibrinolytics (tranexamic acid (TXA), aprotinin, epsilon-aminocaproic acid (EACA)), desmopressin, factor VIIa and XIII, fibrinogen, fibrin sealants and non-fibrin sealants.

DATA COLLECTION AND ANALYSIS

We performed the review according to standard Cochrane methodology. Two authors independently assessed trial eligibility and risk of bias, and extracted data. We assessed the certainty of the evidence using CINeMA. We presented direct (pairwise) results using RevMan Web and performed the NMA using BUGSnet. We were interested in the following primary outcomes: need for allogenic blood transfusion (up to 30 days) and all-cause mortality (deaths occurring up to 30 days after the operation), and the following secondary outcomes: mean number of transfusion episodes per person (up to 30 days), re-operation due to bleeding (within seven days), length of hospital stay and adverse events related to the intervention received.

MAIN RESULTS

We included a total of 102 studies. Twelve studies did not report the number of included participants; the other 90 studies included 8418 participants. Trials included more women (64%) than men (36%). In the NMA for allogeneic blood transfusion, we included 47 studies (4398 participants). Most studies examined TXA (58 arms, 56%). We found that TXA, given intra-articularly and orally at a total dose of greater than 3 g pre-incision, intraoperatively and postoperatively, ranked the highest, with an anticipated absolute effect of 147 fewer blood transfusions per 1000 people (150 fewer to 104 fewer) (53% chance of ranking 1st) within the NMA (risk ratio (RR) 0.02, 95% credible interval (CrI) 0 to 0.31; moderate-certainty evidence). This was followed by TXA given orally at a total dose of 3 g pre-incision and postoperatively (RR 0.06, 95% CrI 0.00 to 1.34; low-certainty evidence) and TXA given intravenously and orally at a total dose of greater than 3 g intraoperatively and postoperatively (RR 0.10, 95% CrI 0.02 to 0.55; low-certainty evidence). Aprotinin (RR 0.59, 95% CrI 0.36 to 0.96; low-certainty evidence), topical fibrin (RR 0.86, CrI 0.25 to 2.93; very low-certainty evidence) and EACA (RR 0.60, 95% CrI 0.29 to 1.27; very low-certainty evidence) were not shown to be as effective compared with TXA at reducing the risk of blood transfusion. We were unable to perform an NMA for our primary outcome all-cause mortality within 30 days of surgery due to the large number of studies with zero events, or because the outcome was not reported. In the NMA for deep vein thrombosis (DVT), we included 19 studies (2395 participants). Most studies examined TXA (27 arms, 64%). No studies assessed desmopressin, EACA or topical fibrin. We found that TXA given intravenously and orally at a total dose of greater than 3 g intraoperatively and postoperatively ranked the highest, with an anticipated absolute effect of 67 fewer DVTs per 1000 people (67 fewer to 34 more) (26% chance of ranking first) within the NMA (RR 0.16, 95% CrI 0.02 to 1.43; low-certainty evidence). This was followed by TXA given intravenously and intra-articularly at a total dose of 2 g pre-incision and intraoperatively (RR 0.21, 95% CrI 0.00 to 9.12; low-certainty evidence) and TXA given intravenously and intra-articularly, total dose greater than 3 g pre-incision, intraoperatively and postoperatively (RR 0.13, 95% CrI 0.01 to 3.11; low-certainty evidence). Aprotinin was not shown to be as effective compared with TXA (RR 0.67, 95% CrI 0.28 to 1.62; very low-certainty evidence). We were unable to perform an NMA for our secondary outcomes pulmonary embolism, myocardial infarction and CVA (stroke) within 30 days, mean number of transfusion episodes per person (up to 30 days), re-operation due to bleeding (within seven days), or length of hospital stay, due to the large number of studies with zero events, or because the outcome was not reported by enough studies to build a network. There are 30 ongoing trials planning to recruit 3776 participants, the majority examining TXA (26 trials).

AUTHORS' CONCLUSIONS

We found that of all the interventions studied, TXA is probably the most effective intervention for preventing bleeding in people undergoing hip or knee replacement surgery. Aprotinin and EACA may not be as effective as TXA at preventing the need for allogeneic blood transfusion. We were not able to draw strong conclusions on the optimal dose, route and timing of administration of TXA. We found that TXA given at higher doses tended to rank higher in the treatment hierarchy, and we also found that it may be more beneficial to use a mixed route of administration (oral and intra-articular, oral and intravenous, or intravenous and intra-articular). Oral administration may be as effective as intravenous administration of TXA. We found little to no evidence of harm associated with higher doses of tranexamic acid in the risk of DVT. However, we are not able to definitively draw these conclusions based on the trials included within this review.

Cell salvage for minimising perioperative allogeneic blood transfusion in adults undergoing elective surgery

BACKGROUND

Concerns regarding the safety and availability of transfused donor blood have prompted research into a range of techniques to minimise allogeneic transfusion requirements. Cell salvage (CS) describes the recovery of blood from the surgical field, either during or after surgery, for reinfusion back to the patient.

OBJECTIVES

To examine the effectiveness of CS in minimising perioperative allogeneic red blood cell transfusion and on other clinical outcomes in adults undergoing elective or non-urgent surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases and two clinical trials registers for randomised controlled trials (RCTs) and systematic reviews from 2009 (date of previous search) to 19 January 2023, without restrictions on language or publication status.

SELECTION CRITERIA

We included RCTs assessing the use of CS compared to no CS in adults (participants aged 18 or over, or using the study's definition of adult) undergoing elective (non-urgent) surgery only.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 106 RCTs, incorporating data from 14,528 participants, reported in studies conducted in 24 countries. Results were published between 1978 and 2021. We analysed all data according to a single comparison: CS versus no CS. We separated analyses by type of surgery. The certainty of the evidence varied from very low certainty to high certainty. Reasons for downgrading the certainty included imprecision (small sample sizes below the optimal information size required to detect a difference, and wide confidence intervals), inconsistency (high statistical heterogeneity), and risk of bias (high risk from domains including sequence generation, blinding, and baseline imbalances). Aggregate analysis (all surgeries combined: primary outcome only) Very low-certainty evidence means we are uncertain if there is a reduction in the risk of allogeneic transfusion with CS (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.59 to 0.72; 82 RCTs, 12,520 participants). Cancer: 2 RCTs (79 participants) Very low-certainty evidence means we are uncertain whether there is a difference for mortality, blood loss, infection, or deep vein thrombosis (DVT). There were no analysable data reported for the remaining outcomes. Cardiovascular (vascular): 6 RCTs (384 participants) Very low- to low-certainty evidence means we are uncertain whether there is a difference for most outcomes. No data were reported for major adverse cardiovascular events (MACE). Cardiovascular (no bypass): 6 RCTs (372 participants) Moderate-certainty evidence suggests there is probably a reduction in risk of allogeneic transfusion with CS (RR 0.82, 95% CI 0.69 to 0.97; 3 RCTs, 169 participants). Very low- to low-certainty evidence means we are uncertain whether there is a difference for volume transfused, blood loss, mortality, re-operation for bleeding, infection, wound complication, myocardial infarction (MI), stroke, and hospital length of stay (LOS). There were no analysable data reported for thrombosis, DVT, pulmonary embolism (PE), and MACE. Cardiovascular (with bypass): 29 RCTs (2936 participants) Low-certainty evidence suggests there may be a reduction in the risk of allogeneic transfusion with CS, and suggests there may be no difference in risk of infection and hospital LOS. Very low- to moderate-certainty evidence means we are uncertain whether there is a reduction in volume transfused because of CS, or if there is any difference for mortality, blood loss, re-operation for bleeding, wound complication, thrombosis, DVT, PE, MACE, and MI, and probably no difference in risk of stroke. Obstetrics: 1 RCT (1356 participants) High-certainty evidence shows there is no difference between groups for mean volume of allogeneic blood transfused (mean difference (MD) -0.02 units, 95% CI -0.08 to 0.04; 1 RCT, 1349 participants). Low-certainty evidence suggests there may be no difference for risk of allogeneic transfusion. There were no analysable data reported for the remaining outcomes. Orthopaedic (hip only): 17 RCTs (2055 participants) Very low-certainty evidence means we are uncertain if CS reduces the risk of allogeneic transfusion, and the volume transfused, or if there is any difference between groups for mortality, blood loss, re-operation for bleeding, infection, wound complication, prosthetic joint infection (PJI), thrombosis, DVT, PE, stroke, and hospital LOS. There were no analysable data reported for MACE and MI. Orthopaedic (knee only): 26 RCTs (2568 participants) Very low- to low-certainty evidence means we are uncertain if CS reduces the risk of allogeneic transfusion, and the volume transfused, and whether there is a difference for blood loss, re-operation for bleeding, infection, wound complication, PJI, DVT, PE, MI, MACE, stroke, and hospital LOS. There were no analysable data reported for mortality and thrombosis. Orthopaedic (spine only): 6 RCTs (404 participants) Moderate-certainty evidence suggests there is probably a reduction in the need for allogeneic transfusion with CS (RR 0.44, 95% CI 0.31 to 0.63; 3 RCTs, 194 participants). Very low- to moderate-certainty evidence suggests there may be no difference for volume transfused, blood loss, infection, wound complication, and PE. There were no analysable data reported for mortality, re-operation for bleeding, PJI, thrombosis, DVT, MACE, MI, stroke, and hospital LOS. Orthopaedic (mixed): 14 RCTs (4374 participants) Very low- to low-certainty evidence means we are uncertain if there is a reduction in the need for allogeneic transfusion with CS, or if there is any difference between groups for volume transfused, mortality, blood loss, infection, wound complication, PJI, thrombosis, DVT, MI, and hospital LOS. There were no analysable data reported for re-operation for bleeding, MACE, and stroke.

AUTHORS' CONCLUSIONS

In some types of elective surgery, cell salvage may reduce the need for and volume of allogeneic transfusion, alongside evidence of no difference in adverse events, when compared to no cell salvage. Further research is required to establish why other surgeries show no benefit from CS, through further analysis of the current evidence. More large RCTs in under-reported specialities are needed to expand the evidence base for exploring the impact of CS.

Interventions for chronic kidney disease in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD), one of the commonest severe monogenic disorders, is caused by the inheritance of two abnormal haemoglobin (beta-globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Kidney disease is a frequent and potentially severe complication in people with SCD. Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function present for more than three months. Sickle cell nephropathy refers to the spectrum of kidney complications in SCD. Glomerular damage is a cause of microalbuminuria and can develop at an early age in children with SCD, with increased prevalence in adulthood. In people with sickle cell nephropathy, outcomes are poor as a result of the progression to proteinuria and chronic kidney insufficiency. Up to 12% of people who develop sickle cell nephropathy will develop end-stage renal disease. This is an update of a review first published in 2017.

OBJECTIVES

To assess the effectiveness of any intervention for preventing or reducing kidney complications or chronic kidney disease in people with sickle cell disease. Possible interventions include red blood cell transfusions, hydroxyurea, and angiotensin-converting enzyme inhibitors (ACEIs), either alone or in combination.

SEARCH METHODS

We searched for relevant trials in the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, CENTRAL, MEDLINE, Embase, seven other databases, and two other trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing interventions to prevent or reduce kidney complications or CKD in people with SCD. We applied no restrictions related to outcomes examined, language, or publication status.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility, extracted data, assessed the risk of bias, and assessed the certainty of the evidence (GRADE).

MAIN RESULTS

We included three RCTs with 385 participants. We rated the certainty of the evidence as low to very low across different outcomes according to GRADE methodology, downgrading for risk of bias concerns, indirectness, and imprecision. Hydroxyurea versus placebo One RCT published in 2011 compared hydroxyurea to placebo in 193 children aged nine to 18 months. We are unsure if hydroxyurea compared to placebo reduces or prevents progression of kidney disease assessed by change in glomerular filtration rate (mean difference (MD) 0.58 mL/min /1.73 m2, 95% confidence interval (CI) -14.60 to 15.76; 142 participants; very low certainty). Hydroxyurea compared to placebo may improve the ability to concentrate urine (MD 42.23 mOsm/kg, 95% CI 12.14 to 72.32; 178 participants; low certainty), and may make little or no difference to SCD-related serious adverse events, including acute chest syndrome (risk ratio (RR) 0.39, 99% CI 0.13 to 1.16; 193 participants; low certainty), painful crisis (RR 0.68, 99% CI 0.45 to 1.02; 193 participants; low certainty); and hospitalisations (RR 0.83, 99% CI 0.68 to 1.01; 193 participants; low certainty). No deaths occurred in either trial arm and the RCT did not report quality of life. Angiotensin-converting enzyme inhibitors versus placebo One RCT published in 1998 compared an ACEI (captopril) to placebo in 22 adults with normal blood pressure and microalbuminuria. We are unsure if captopril compared to placebo reduces proteinuria (MD -49.00 mg/day, 95% CI -124.10 to 26.10; 22 participants; very low certainty). We are unsure if captopril reduces or prevents kidney disease as measured by creatinine clearance; the trial authors stated that creatinine clearance remained constant over six months in both groups, but provided no comparative data (very low certainty). The RCT did not report serious adverse events, all-cause mortality, or quality of life. Angiotensin-converting enzyme inhibitors versus vitamin C One RCT published in 2020 compared an ACEI (lisinopril) with vitamin C in 170 children aged one to 18 years with normal blood pressure and microalbuminuria. It reported no data we could analyse. We are unsure if lisinopril compared to vitamin C reduces proteinuria in this population: the large drop in microalbuminuria in both arms of the trial after only one month on treatment may have been due to an overestimation of microalbuminuria at baseline rather than a true effect. The RCT did not report serious adverse events, all-cause mortality, or quality of life.

AUTHORS' CONCLUSIONS

We are unsure if hydroxyurea improves glomerular filtration rate or reduces hyperfiltration in children aged nine to 18 months, but it may improve their ability to concentrate urine and may make little or no difference to the incidence of acute chest syndrome, painful crises, and hospitalisations. We are unsure if ACEI compared to placebo has any effect on preventing or reducing kidney complications in adults with normal blood pressure and microalbuminuria. We are unsure if ACEI compared to vitamin C has any effect on preventing or reducing kidney complications in children with normal blood pressure and microalbuminuria. No RCTs assessed red blood cell transfusions or any combined interventions to prevent or reduce kidney complications. Due to lack of evidence, we cannot comment on the management of children aged over 18 months or adults with any known genotype of SCD. We have identified a lack of adequately designed and powered studies, although we found four ongoing trials since the last version of this review. Only one ongoing trial addresses renal function as a primary outcome in the short term, but such interventions have long-term effects. Trials of hydroxyurea, ACEIs or red blood cell transfusion in older children and adults are urgently needed to determine any effect on prevention or reduction of kidney complications in people with SCD.

Pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic and long bone fractures

BACKGROUND

Pelvic, hip, and long bone fractures can result in significant bleeding at the time of injury, with further blood loss if they are treated with surgical fixation. People undergoing surgery are therefore at risk of requiring a blood transfusion and may be at risk of peri-operative anaemia. Pharmacological interventions for blood conservation may reduce the risk of requiring an allogeneic blood transfusion and associated complications.

OBJECTIVES

To assess the effectiveness of different pharmacological interventions for reducing blood loss in definitive surgical fixation of the hip, pelvic, and long bones.

SEARCH METHODS

We used a predefined search strategy to search CENTRAL, MEDLINE, PubMed, Embase, CINAHL, Transfusion Evidence Library, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) from inception to 7 April 2022, without restrictions on language, year, or publication status. We handsearched reference lists of included trials to identify further relevant trials. We contacted authors of ongoing trials to acquire any unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of people who underwent trauma (non-elective) surgery for definitive fixation of hip, pelvic, and long bone (pelvis, tibia, femur, humerus, radius, ulna and clavicle) fractures only. There were no restrictions on gender, ethnicity, or age. We excluded planned (elective) procedures (e.g. scheduled total hip arthroplasty), and studies published since 2010 that had not been prospectively registered. Eligible interventions included: antifibrinolytics (tranexamic acid, aprotinin, epsilon-aminocaproic acid), desmopressin, factor VIIa and XIII, fibrinogen, fibrin sealants, and non-fibrin sealants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted data. We assessed the certainty of the evidence using GRADE. We did not perform a network meta-analysis due to lack of data.

MAIN RESULTS

We included 13 RCTs (929 participants), published between 2005 and 2021. Three trials did not report any of our predefined outcomes and so were not included in quantitative analyses (all were tranexamic acid versus placebo). We identified three comparisons of interest: intravenous tranexamic acid versus placebo; topical tranexamic acid versus placebo; and recombinant factor VIIa versus placebo. We rated the certainty of evidence as very low to low across all outcomes. Comparison 1. Intravenous tranexamic acid versus placebo Intravenous tranexamic acid compared to placebo may reduce the risk of requiring an allogeneic blood transfusion up to 30 days (RR 0.48, 95% CI 0.34 to 0.69; 6 RCTs, 457 participants; low-certainty evidence) and may result in little to no difference in all-cause mortality (Peto odds ratio (Peto OR) 0.38, 95% CI 0.05 to 2.77; 2 RCTs, 147 participants; low-certainty evidence).  It may result in little to no difference in risk of participants experiencing myocardial infarction (risk difference (RD) 0.00, 95% CI -0.03 to 0.03; 2 RCTs, 199 participants; low-certainty evidence), and cerebrovascular accident/stroke (RD 0.00, 95% CI -0.02 to 0.02; 3 RCTs, 324 participants; low-certainty evidence).  We are uncertain if there is a difference between groups for risk of deep vein thrombosis (Peto OR 2.15, 95% CI 0.22 to 21.35; 4 RCTs, 329 participants, very low-certainty evidence), pulmonary embolism (Peto OR 1.08, 95% CI 0.07 to 17.66; 4 RCTs, 329 participants; very low-certainty evidence), and suspected serious drug reactions (RD 0.00, 95% CI -0.03 to 0.03; 2 RCTs, 185 participants; very low-certainty evidence). No data were available for number of red blood cell units transfused, reoperation, or acute transfusion reaction. We downgraded the certainty of the evidence for imprecision (wide confidence intervals around the estimate and small sample size, particularly for rare events), and risk of bias (unclear or high risk methods of blinding and allocation concealment in the assessment of subjective measures), and upgraded the evidence for transfusion requirement for a large effect.  Comparison 2. Topical tranexamic acid versus placebo We are uncertain if there is a difference between topical tranexamic acid and placebo for risk of requiring an allogeneic blood transfusion (RR 0.31, 95% CI 0.08 to 1.22; 2 RCTs, 101 participants), all-cause mortality (RD 0.00, 95% CI -0.10 to 0.10; 1 RCT, 36 participants), risk of participants experiencing myocardial infarction (Peto OR 0.15, 95% CI 0.00 to 7.62; 1 RCT, 36 participants), cerebrovascular accident/stroke (RD 0.00, 95% CI -0.06 to 0.06; 1 RCT, 65 participants); and deep vein thrombosis (Peto OR 1.11, 95% CI 0.07 to 17.77; 2 RCTs, 101 participants).  All outcomes reported were very low-certainty evidence. No data were available for number of red blood cell units transfused, reoperation, incidence of pulmonary embolism, acute transfusion reaction, or suspected serious drug reactions. We downgraded the certainty of the evidence for imprecision (wide confidence intervals around the estimate and small sample size, particularly for rare events), inconsistency (moderate heterogeneity), and risk of bias (unclear or high risk methods of blinding and allocation concealment in the assessment of subjective measures, and high risk of attrition and reporting biases in one trial). Comparison 3. Recombinant factor VIIa versus placebo   Only one RCT of 48 participants reported data for recombinant factor VIIa versus placebo, so we have not presented the results here.

AUTHORS' CONCLUSIONS

We cannot draw conclusions from the current evidence due to lack of data. Most published studies included in our analyses assessed the use of tranexamic acid (compared to placebo, or using different routes of administration).  We identified 27 prospectively registered ongoing RCTs (total target recruitment of 4177 participants by end of 2023). The ongoing trials create six new comparisons: tranexamic acid (tablet + injection) versus placebo; intravenous tranexamic acid versus oral tranexamic acid; topical tranexamic acid versus oral tranexamic acid; different intravenous tranexamic acid dosing regimes; topical tranexamic acid versus topical fibrin glue; and fibrinogen (injection) versus placebo.

Interventions for improving adherence to iron chelation therapy in people with sickle cell disease or thalassaemia

BACKGROUND

Regularly transfused people with sickle cell disease (SCD) and people with thalassaemia are at risk of iron overload. Iron overload can lead to iron toxicity in vulnerable organs such as the heart, liver and endocrine glands, which can be prevented and treated with iron-chelating agents. The intensive demands and uncomfortable side effects of therapy can have a negative impact on daily activities and wellbeing, which may affect adherence.

OBJECTIVES

To identify and assess the effectiveness of different types of interventions (psychological and psychosocial, educational, medication interventions, or multi-component interventions) and interventions specific to different age groups, to improve adherence to iron chelation therapy compared to another listed intervention, or standard care in people with SCD or thalassaemia.

SEARCH METHODS

We searched CENTRAL (Cochrane Library), MEDLINE, PubMed, Embase, CINAHL, PsycINFO, ProQuest Dissertations & Global Theses, Web of Science & Social Sciences Conference Proceedings Indexes and ongoing trial databases (13 December 2021). We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register (1 August 2022).

SELECTION CRITERIA

For trials comparing medications or medication changes, only randomised controlled trials (RCTs) were eligible for inclusion. For studies including psychological and psychosocial interventions, educational interventions, or multi-component interventions, non-randomised studies of interventions (NRSIs), controlled before-after studies, and interrupted time series studies with adherence as a primary outcome were also eligible for inclusion.

DATA COLLECTION AND ANALYSIS

For this update, two authors independently assessed trial eligibility and risk of bias, and extracted data. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 19 RCTs and one NRSI published between 1997 and 2021. One trial assessed medication management, one assessed an education intervention (NRSI) and 18 RCTs were of medication interventions. Medications assessed were subcutaneous deferoxamine, and two oral chelating agents, deferiprone and deferasirox. We rated the certainty of evidence as very low to low across all outcomes identified in this review. Four trials measured quality of life (QoL) with validated instruments, but provided no analysable data and reported no difference in QoL. We identified nine comparisons of interest. 1. Deferiprone versus deferoxamine We are uncertain whether or not deferiprone affects adherence to iron chelation therapy (four RCTs, unpooled, very low-certainty evidence), all-cause mortality (risk ratio (RR) 0.47, 95% confidence interval (CI) 0.18 to 1.21; 3 RCTs, 376 participants; very low-certainty evidence), or serious adverse events (SAEs) (RR 1.43, 95% CI 0.83 to 2.46; 1 RCT, 228 participants; very low-certainty evidence).  Adherence was reported as "good", "high" or "excellent" by all seven trials, though the data could not be analysed formally: adherence ranged from 69% to 95% (deferiprone, mean 86.6%), and 71% to 93% (deferoxamine, mean 78.8%), based on five trials (474 participants) only. 2. Deferasirox versus deferoxamine We are uncertain whether or not deferasirox affects adherence to iron chelation therapy (three RCTs, unpooled, very low-certainty evidence), although medication adherence was high in all trials. We are uncertain whether or not there is any difference between the drug therapies in serious adverse events (SAEs) (SCD or thalassaemia) or all-cause mortality (thalassaemia). 3. Deferiprone versus deferasirox We are uncertain if there is a difference between oral deferiprone and deferasirox based on a single trial in children (average age 9 to 10 years) with any hereditary haemoglobinopathy in adherence, SAEs and all-cause mortality. 4. Deferasirox film-coated tablet (FCT) versus deferasirox dispersible tablet (DT) One RCT compared deferasirox in different tablet forms. There may be a preference for FCTs, shown through a trend for greater adherence (RR 1.10, 95% CI 0.99 to 1.22; 1 RCT, 88 participants), although medication adherence was high in both groups (FCT 92.9%; DT 85.3%). We are uncertain if there is a benefit in chelation-related AEs with FCTs. We are uncertain if there is a difference in the incidence of SAEs, all-cause mortality or sustained adherence. 5. Deferiprone and deferoxamine combined versus deferiprone alone We are uncertain if there is a difference in adherence, though reporting was usually narrative as triallists report it was "excellent" in both groups (three RCTs, unpooled). We are uncertain if there is a difference in the incidence of SAEs and all-cause mortality.  6. Deferiprone and deferoxamine combined versus deferoxamine alone We are uncertain if there is a difference in adherence (four RCTs), SAEs (none reported in the trial period) and all-cause mortality (no deaths reported in the trial period). There was high adherence in all trials. 7. Deferiprone and deferoxamine combined versus deferiprone and deferasirox combined There may be a difference in favour of deferiprone and deferasirox (combined) in rates of adherence (RR 0.84, 95% CI 0.72 to 0.99) (one RCT), although it was high (> 80%) in both groups. We are uncertain if there is a difference in SAEs, and no deaths were reported in the trial, so we cannot draw conclusions based on these data (one RCT). 8. Medication management versus standard care We are uncertain if there is a difference in QoL (one RCT), and we could not assess adherence due to a lack of reporting in the control group. 9. Education versus standard care One quasi-experimental (NRSI) study could not be analysed due to the severe baseline confounding.

AUTHORS' CONCLUSIONS

The medication comparisons included in this review had higher than average adherence rates not accounted for by differences in medication administration or side effects, though often follow-up was not good (high dropout over longer trials), with adherence based on a per protocol analysis. Participants may have been selected based on higher adherence to trial medications at baseline. Also, within the clinical trial context, there is increased attention and involvement of clinicians, thus high adherence rates may be an artefact of trial participation. Real-world, pragmatic trials in community and clinic settings are needed that examine both confirmed or unconfirmed adherence strategies that may increase adherence to iron chelation therapy. Due to lack of evidence this review cannot comment on intervention strategies for different age groups.

Drugs to reduce bleeding and transfusion in major open vascular or endovascular surgery: a systematic review and network meta-analysis

BACKGROUND

Vascular surgery may be followed by internal bleeding due to inadequate surgical haemostasis, abnormal clotting, or surgical complications. Bleeding ranges from minor, with no transfusion requirement, to massive, requiring multiple blood product transfusions. There are a number of drugs, given systemically or applied locally, which may reduce the need for blood transfusion.

OBJECTIVES

To assess the effectiveness and safety of anti-fibrinolytic and haemostatic drugs and agents in reducing bleeding and the need for blood transfusion in people undergoing major vascular surgery or vascular procedures with a risk of moderate or severe (> 500 mL) blood loss.

SEARCH METHODS

We searched: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL, and Transfusion Evidence Library. We also searched the WHO ICTRP and ClinicalTrials.gov trial registries for ongoing and unpublished trials. Searches used a combination of MeSH and free text terms from database inception to 31 March 2022, without restriction on language or publication status.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in adults of drug treatments to reduce bleeding due to major vascular surgery or vascular procedures with a risk of moderate or severe blood loss, which used placebo, usual care or another drug regimen as control.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were units of red cells transfused and all-cause mortality. Our secondary outcomes included risk of receiving an allogeneic blood product, risk of reoperation or repeat procedure due to bleeding, risk of a thromboembolic event, risk of a serious adverse event and length of hospital stay. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included 22 RCTs with 3393 participants analysed, of which one RCT with 69 participants was reported only in abstract form, with no usable data. Seven RCTs evaluated systemic drug treatments (three aprotinin, two desmopressin, two tranexamic acid) and 15 RCTs evaluated topical drug treatments (drug-containing bioabsorbable dressings or glues), including fibrin, thrombin, collagen, gelatin, synthetic sealants and one investigational new agent. Most trials were conducted in high-income countries and the majority of the trials only included participants undergoing elective surgery. We also identified two ongoing RCTs. We were unable to perform the planned network meta-analysis due to the sparse reporting of outcomes relevant to this review. Systemic drug treatments We identified seven trials of three systemic drugs: aprotinin, desmopressin and tranexamic acid, all with placebo controls. The trials of aprotinin and desmopressin were small with very low-certainty evidence for all of our outcomes. Tranexamic acid versus placebo was the systemic drug comparison with the largest number of participants (2 trials; 1460 participants), both at low risk of bias. The largest of these included a total of 9535 individuals undergoing a number of different higher risk surgeries and reported limited information on the vascular subgroup (1399 participants). Neither trial reported the number of units of red cells transfused per participant up to 30 days. Three outcomes were associated with very low-certainty evidence due to the very wide confidence intervals (CIs) resulting from small study sizes and low number of events. These were: all-cause mortality up to 30 days; number of participants requiring an allogeneic blood transfusion up to 30 days; and risk of requiring a repeat procedure or operation due to bleeding. Tranexamic acid may have no effect on the risk of thromboembolic events up to 30 days (risk ratio (RR) 1.10, 95% CI 0.88 to 1.36; 1 trial, 1360 participants; low-certainty evidence due to imprecision). There is one large ongoing trial (8320 participants) comparing tranexamic acid versus placebo in people undergoing non-cardiac surgery who are at high risk of requiring a red cell transfusion. This aims to complete recruitment in April 2023. This trial has primary outcomes of proportion of participants transfused with red blood cells and incidence of venous thromboembolism (DVT or PE). Topical drug treatments Most trials of topical drug treatments were at high risk of bias due to their open-label design (compared with usual care, or liquids were compared with sponges). All of the trials were small, most were very small, and few reported clinically relevant outcomes in the postoperative period. Fibrin sealant versus usual care was the topical drug comparison with the largest number of participants (5 trials, 784 participants). The five trials that compared fibrin sealant with usual care were all at high risk of bias, due to the open-label trial design with no measures put in place to minimise reporting bias. All of the trials were funded by pharmaceutical companies. None of the five trials reported the number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. The other three outcomes were associated with very low-certainty evidence with wide confidence intervals due to small sample sizes and the low number of events, these were: all-cause mortality up to 30 days; risk of requiring a repeat procedure due to bleeding; and risk of thromboembolic disease up to 30 days. We identified one large trial (500 participants) comparing fibrin sealant versus usual care in participants undergoing abdominal aortic aneurysm repair, which has not yet started recruitment. This trial lists death due to arterial disease and reintervention rates as primary outcomes.

AUTHORS' CONCLUSIONS

Because of a lack of data, we are uncertain whether any systemic or topical treatments used to reduce bleeding due to major vascular surgery have an effect on: all-cause mortality up to 30 days; risk of requiring a repeat procedure or operation due to bleeding; number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. There may be no effect of tranexamic acid on the risk of thromboembolic events up to 30 days, this is important as there has been concern that this risk may be increased. Trials with sample size targets of thousands of participants and clinically relevant outcomes are needed, and we look forward to seeing the results of the ongoing trials in the future.

A systematic review of the safety and efficacy of convalescent plasma or immunoglobulin treatment for people with severe respiratory viral infections due to coronaviruses or influenza

OBJECTIVE

Evaluate the safety and effectiveness of convalescent plasma (CP) or hyperimmune immunoglobulin (hIVIG) in severe respiratory disease caused by coronaviruses or influenza, in patients of all ages requiring hospital admission.

METHODS

We searched multiple electronic databases for all publications to 12th October 2020, and RCTs only to 28th June 2021. Two reviewers screened, extracted, and analysed data. We used Cochrane ROB (Risk of Bias)1 for RCTs, ROBINS-I for non-RCTs, and GRADE to assess the certainty of the evidence.

RESULTS

Data from 30 RCTs and 2 non-RCTs showed no overall difference between groups for all-cause mortality and adverse events in four comparisons. Certainty of the evidence was downgraded for high ROB and imprecision. (1) CP versus standard care (SoC) (20 RCTS, 2 non-RCTs, very-low to moderate-high certainty); (2) CP versus biologically active control (6 RCTs, very-low certainty); (3) hIVIG versus SoC (3 RCTs, very-low certainty); (4) early CP versus deferred CP (1 RCT, very-low certainty). Subgrouping by titre improved precision in one outcome (30-day mortality) for the 'COVID high-titre' category in Comparison 1 (no difference, high certainty) and Comparison 2 (favours CP, very-low certainty). Post hoc analysis suggests a possible benefit of CP in patients testing negative for antibodies at baseline, compared with those testing positive.

CONCLUSION

A minimum titre should be established and ensured for a positive biological response to the therapy. Further research on the impact of CP/hIVIG in patients who have not yet produced antibodies to the virus would be useful to target therapies at groups who will potentially benefit the most.

Transfusion thresholds for guiding red blood cell transfusion

BACKGROUND

The optimal haemoglobin threshold for use of red blood cell (RBC) transfusions in anaemic patients remains an active field of research. Blood is a scarce resource, and in some countries, transfusions are less safe than in others because of inadequate testing for viral pathogens. If a liberal transfusion policy does not improve clinical outcomes, or if it is equivalent, then adopting a more restrictive approach could be recognised as the standard of care.  OBJECTIVES: The aim of this review update was to compare 30-day mortality and other clinical outcomes for participants randomised to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all clinical conditions. The restrictive transfusion threshold uses a lower haemoglobin concentration as a threshold for transfusion (most commonly, 7.0 g/dL to 8.0 g/dL), and the liberal transfusion threshold uses a higher haemoglobin concentration as a threshold for transfusion (most commonly, 9.0 g/dL to 10.0 g/dL).

SEARCH METHODS

We identified trials through updated searches: CENTRAL (2020, Issue 11), MEDLINE (1946 to November 2020), Embase (1974 to November 2020), Transfusion Evidence Library (1950 to November 2020), Web of Science Conference Proceedings Citation Index (1990 to November 2020), and trial registries (November 2020). We  checked the reference lists of other published reviews and relevant papers to identify additional trials. We were aware of one trial identified in earlier searching that was in the process of being published (in February 2021), and we were able to include it before this review was finalised.

SELECTION CRITERIA

We included randomised trials of surgical or medical participants that recruited adults or children, or both. We excluded studies that focused on neonates. Eligible trials assigned intervention groups on the basis of different transfusion schedules or thresholds or 'triggers'. These thresholds would be defined by a haemoglobin (Hb) or haematocrit (Hct) concentration below which an RBC transfusion would be administered; the haemoglobin concentration remains the most commonly applied marker of the need for RBC transfusion in clinical practice. We included trials in which investigators had allocated participants to higher thresholds or more liberal transfusion strategies compared to more restrictive ones, which might include no transfusion. As in previous versions of this review, we did not exclude unregistered trials published after 2010 (as per the policy of the Cochrane Injuries Group, 2015), however, we did conduct analyses to consider the differential impact of results of trials for which prospective registration could not be confirmed.   DATA COLLECTION AND ANALYSIS: We identified trials for inclusion and extracted data using Cochrane methods. We pooled risk ratios of clinical outcomes across trials using a random-effects model. Two review authors independently extracted data and assessed risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as being in the 'restrictive transfusion' group and those randomly allocated to the higher transfusion threshold as being in the 'liberal transfusion' group.

MAIN RESULTS

A total of 48 trials, involving data from 21,433 participants (at baseline), across a range of clinical contexts (e.g. orthopaedic, cardiac, or vascular surgery; critical care; acute blood loss (including gastrointestinal bleeding); acute coronary syndrome; cancer; leukaemia; haematological malignancies), met the eligibility criteria. The haemoglobin concentration used to define the restrictive transfusion group in most trials (36) was between 7.0 g/dL and 8.0 g/dL.  Most trials included only adults; three trials focused on children. The included studies were generally at low risk of bias for key domains including allocation concealment and incomplete outcome data. Restrictive transfusion strategies reduced the risk of receiving at least one RBC transfusion by 41% across a broad range of clinical contexts (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.53 to 0.66; 42 studies, 20,057 participants; high-quality evidence), with a large amount of heterogeneity between trials (I² = 96%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.99, 95% CI 0.86 to 1.15; 31 studies, 16,729 participants; I² = 30%; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (all high-quality evidence)). High-quality evidence shows that the liberal transfusion threshold did not affect the risk of infection (pneumonia, wound infection, or bacteraemia). Transfusion-specific reactions are uncommon and were inconsistently reported within trials. We noted less certainty in the strength of evidence to support the safety of restrictive transfusion thresholds for the following predefined clinical subgroups: myocardial infarction, vascular surgery, haematological malignancies, and chronic bone-marrow disorders.

AUTHORS' CONCLUSIONS

Transfusion at a restrictive haemoglobin concentration decreased the proportion of people exposed to RBC transfusion by 41% across a broad range of clinical contexts. Across all trials, no evidence suggests that a restrictive transfusion strategy impacted 30-day mortality, mortality at other time points, or morbidity (i.e. cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. Despite including 17 more randomised trials (and 8846 participants), data remain insufficient to inform the safety of transfusion policies in important and selected clinical contexts, such as myocardial infarction, chronic cardiovascular disease, neurological injury or traumatic brain injury, stroke, thrombocytopenia, and cancer or haematological malignancies, including chronic bone marrow failure.  Further work is needed to improve our understanding of outcomes other than mortality. Most trials compared only two separate thresholds for haemoglobin concentration, which may not identify the actual optimal threshold for transfusion in a particular patient. Haemoglobin concentration may not be the most informative marker of the need for transfusion in individual patients with different degrees of physiological adaptation to anaemia. Notwithstanding these issues, overall findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds between the range of 7.0 g/dL and 8.0 g/dL. Some patient subgroups might benefit from RBCs to maintain higher haemoglobin concentrations; research efforts should focus on these clinical contexts.

Restrictive versus liberal blood transfusion for gastrointestinal bleeding: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Acute upper gastrointestinal bleeding is a leading indication for red blood cell (RBC) transfusion worldwide, although optimal thresholds for transfusion are debated.

METHODS

We searched MEDLINE, Embase, CENTRAL, CINAHL, and the Transfusion Evidence Library from inception to Oct 20, 2016, for randomised controlled trials comparing restrictive and liberal RBC transfusion strategies for acute upper gastrointestinal bleeding. Main outcomes were mortality, rebleeding, ischaemic events, and mean RBC transfusion. We computed pooled estimates for each outcome by random effects meta-analysis, and individual participant data for a cluster randomised trial were re-analysed to facilitate meta-analysis. We compared treatment effects between patient subgroups, including patients with liver cirrhosis, patients with non-variceal upper gastrointestinal bleeding, and patients with ischaemic heart disease at baseline.

FINDINGS

We included four published and one unpublished randomised controlled trial, totalling 1965 participants. The number of RBC units transfused was lower in the restrictive transfusion group than in the liberal transfusion group (mean difference -1·73 units, 95% CI -2·36 to -1·11, p<0·0001). Restrictive transfusion was associated with lower risk of all-cause mortality (relative risk [RR] 0·65, 95% CI 0·44-0·97, p=0·03) and rebleeding overall (0·58, 0·40-0·84, p=0·004). We detected no difference in risk of ischaemic events. There were no statistically significant differences in the subgroups.

INTERPRETATION

These results support more widespread implementation of restrictive transfusion policies for adults with acute upper gastrointestinal bleeding.

FUNDING

None.

Increased regulatory T cell graft content is associated with improved outcome in haematopoietic stem cell transplantation: a systematic review

Allogeneic haematopoietic stem cell transplant (HSCT) recipients are at increased risk of morbidity and mortality, often due to the development of acute or chronic graft-versus-host disease (GVHD). Low numbers or proportions of regulatory T cells (Tregs) have been reported in patients who develop GVHD. We undertook a systematic review of studies that reported the Treg composition of HSCT grafts in patients with haematological malignancies. Fourteen eligible studies were identified, eight of which stratified patients by Tregs (absolute dose or ratio to CD3+ or CD4+ cells). Meta-analyses showed that high levels of Tregs in the grafts were associated with improved overall survival [hazard ratio (HR) 0·42, 95% confidence interval (CI) 0·23-0·74, P = 0·003, 2 studies], with a significant reduction in non-relapse mortality (HR 0·30, 95% CI 0·14-0·64, P = 0·002, 2 studies) and a reduced risk of acute GVHD (relative risk (RR) 0·59, 95% CI 0·40-0·89, P = 0·01, 6 studies). The consistency of these findings strongly suggests that the Treg composition of HSCT grafts has a powerful effect on the success of allogeneic HSCT. The major challenge is to translate these findings into better selection of allografts and future donors to provide a substantial improvement in allogeneic HSCT outcomes and practice.

A systematic review of factors associated with the deferral of donors failing to meet low haemoglobin thresholds

BACKGROUND/OBJECTIVES

Blood donors attending a donation session may be deemed ineligible to donate blood due to a failure to meet low haemoglobin (Hb) thresholds. Several studies have identified factors associated with a donor falling below these Hb thresholds. A review of these factors will inform future prospective studies and form the basis for predictive models of deferral due to low Hb.

MATERIALS/METHODS

Studies were identified by searching MEDLINE, EMBASE, The Cochrane Library and the WHO International Clinical Trials Registry from 1980 to September 2012. Demographic data, donor history, haematological/biological factors and the primary outcome of deferral due to low Hb were extracted. Analyses were descriptive and quantitative; pooled odds ratios (ORs) were obtained by meta-analysis.

RESULTS

Fifty-five studies met the inclusion criteria. A consistently higher rate of low Hb deferral was reported in females compared with males; meta-analysis showed a significantly greater risk of deferral due to low Hb in females compared with males in studies with universal Hb thresholds for males and females (OR 14.91, 95% confidence interval (CI) 12.82-17.34) and in studies with sex-specific Hb thresholds (OR 8.19, 95% CI 4.88-13.74). Greater rates of deferral due to low Hb were also associated with increasing age, higher ambient temperature, low body weight, shorter inter-donation interval and in donors of Hispanic or African descent.

CONCLUSION

This work will help to define the criteria that should be considered in any large scale study of blood donor deferral, especially those that measure or aim to change failure to meet low Hb thresholds.

Bone Marrow Stem Cell Treatment for Ischemic Heart Disease in Patients with No Option of Revascularization: A Systematic Review and Meta-Analysis

Objective

To evaluate bone marrow stem cell treatment (BMSC) in patients with ischemic heart disease (IHD) and no option of revascularization.

Background

Autologous BMSC therapy has emerged as a novel approach to treat patients with acute myocardial infarction or chronic ischemia and heart failure following percutaneous or surgical revascularization, respectively. However, the effect of the treatment has not been systematic evaluated in patients who are not eligible for revascularization.

Methods

MEDLINE (1950–2012), EMBASE (1980–2012), CENTRAL (The Cochrane Library 2012, Issue 8) and ongoing trial databases were searched for relevant randomized controlled trials. Trials where participants were diagnosed with IHD, with no option for revascularization and who received any dose of stem cells by any delivery route were selected for inclusion. Study and participant characteristics, details of the intervention and comparator, and outcomes measured were recorded by two reviewers independently. Primary outcome measures were defined as mortality and measures of angina; secondary outcomes were heart failure, quality of life measures, exercise/performance and left ventricular ejection fraction (LVEF).

Results

Nine trials were eligible for inclusion. BMSC treatment significantly reduced the risk of mortality (Relative Risk 0.33; 95% Confidence Interval 0.17 to 0.65; P = 0.001). Patients who received BMSC showed a significantly greater improvement in CCS angina class (Mean Difference −0.55; 95% Confidence Interval −1.00 to −0.10; P = 0.02) and significantly fewer angina episodes per week at the end of the trial (Mean Difference −5.21; 95% Confidence Interval −7.35 to −3.07; P<0.00001) than those who received no BMSC. In addition, the treatment significantly improved quality of life, exercise/performance and LVEF in these patients.

Conclusions

BMSC treatment has significant clinical benefit as stand-alone treatment in patients with IHD and no other treatment option. These results require confirmation in large well-powered trials with long-term follow-up to fully evaluate the clinical efficacy of this treatment.

The acute management of trauma hemorrhage: a systematic review of randomized controlled trials

Introduction

Worldwide, trauma is a leading cause of death and disability. Haemorrhage is responsible for up to 40% of trauma deaths. Recent strategies to improve mortality rates have focused on optimal methods of early hemorrhage control and correction of coagulopathy. We undertook a systematic review of randomized controlled trials (RCT) which evaluated trauma patients with hemorrhagic shock within the first 24 hours of injury and appraised how the interventions affected three outcomes: bleeding and/or transfusion requirements; correction of trauma induced coagulopathy and mortality.

Methods

Comprehensive searches were performed of MEDLINE, EMBASE, CENTRAL (The Cochrane Library Issue 7, 2010), Current Controlled Trials, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) and the National Health Service Blood and Transplant Systematic Review Initiative (NHSBT SRI) RCT Handsearch Database.

Results

A total of 35 RCTs were identified which evaluated a wide range of clinical interventions in trauma hemorrhage. Many of the included studies were of low methodological quality and participant numbers were small. Bleeding outcomes were reported in 32 studies; 7 reported significantly reduced transfusion use following a variety of clinical interventions, but this was not accompanied by improved survival. Minimal information was found on traumatic coagulopathy across the identified RCTs. Overall survival was improved in only three RCTs: two small studies and a large study evaluating the use of tranexamic acid.

Conclusions

Despite 35 RCTs there has been little improvement in outcomes over the last few decades. No clear correlation has been demonstrated between transfusion requirements and mortality. The global trauma community should consider a coordinated and strategic approach to conduct well designed studies with pragmatic endpoints.

Trauma-induced coagulopathy--a review of the systematic reviews: is there sufficient evidence to guide clinical transfusion practice?

Systematic reviews are accepted as a robust and less biased means of appraising and synthesizing results from high-quality studies. This report collated and summarized all the systematic review evidence relating to the diagnosis and management of trauma-related coagulopathy and transfusion, thereby covering the widest possible body of literature. We defined 4 key clinical questions: (1) What are the best methods of predicting and diagnosing trauma-related coagulopathy? (2) Which methods of clinical management correct coagulopathy? (3) Which methods of clinical management correct bleeding? and (4) What are the outcomes of transfusion in trauma? Thirty-seven systematic reviews were identified through searches of MEDLINE (1950-July 2010), EMBASE (1980-July 2010), The Cochrane Library (Issue 7, 2010), National Guidelines Clearing House, National Library for Health Guidelines Finder, and UKBTS SRI Transfusion Evidence Library (www.transfusionevidencelibrary.com). The evidence from the systematic review literature was scanty with many gaps, and we were not able to conclusively answer any of our 4 questions. Much more needs to be understood about how coagulopathy and bleeding in trauma are altered by transfusion practices and, most importantly, whether this translates into improved survival. There is a need for randomized controlled trials to answer these questions. The approach described in this report provides a framework for incorporating new evidence.

Quality of life and use of red cell transfusion in patients with myelodysplastic syndromes. A systematic review

The main treatment for many patients with Myelodysplastic Syndromes (MDS) remains red cell transfusion to attenuate the symptoms of chronic anemia. Fatigue can reduce a patient's health related quality of life (HRQoL), but there is little understanding of the optimal use of transfusions to improve this. A systematic review was performed to identify and appraise publications reporting the use of HRQoL instruments in patients with MDS. A total of 17 separate studies were identified that used 14 HRQoL instruments, but only one MDS disease specific HRQoL instrument (QOL-E) was reported. Two well established HRQoL instruments were most often used in MDS research (variants of the Functional Assessment of Cancer Therapy (FACT) and the European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire (QLQ-C30)). Several common problems were identified in the published literature including a lack of power calculations to detect clinically relevant changes, small sample sizes and significant attrition rates for completion of HRQoL assessments, all of which limit the strength of any conclusions. There is no consensus on the optimal transfusion regimen to improve HRQoL in transfusion-dependent MDS. Future research into HRQoL within MDS is a pressing requirement. Studies should focus on the domains that are of most clinical importance to the patient as well as traditional quantitative changes of hemoglobin concentration.

Stem cell donation--what advice can be given to the donor?

Haematopoietic stem cell transplantation (HSCT) is widely used to treat patients with a range of haematological and non-haematological disorders. Both bone marrow and peripheral blood stem cell collection are associated with morbidity and, very rarely, mortality. We investigated the information that exists to adequately inform donors about the relative merits of each procedure. We carried out a systematic review analysing data from six prospective randomised controlled trials of related donors and discuss here the merits and drawbacks of this approach. Registry data mostly describes patient outcome but stem cell donor registries collect and report information on unrelated donors which could easily be extended to related donors. Further well-designed, randomised studies are required.

Antiviral therapy for Ramsay Hunt syndrome (herpes zoster oticus with facial palsy) in adults

BACKGROUND

Herpes zoster oticus (HZO) is a viral infection of the ear and when associated with acute facial paralysis is known as Ramsay Hunt syndrome. Antiviral agents are the standard first-line treatment for herpes zoster infections at other body sites and are thought to reduce or minimise nerve damage, thereby improving outcomes. It has been suggested that these agents improve the chance of facial weakness improving or resolving completely in patients with Ramsay Hunt syndrome.

OBJECTIVES

To determine the effectiveness of antiviral agents in the treatment of adult patients with Ramsay Hunt syndrome (HZO with facial palsy).

SEARCH STRATEGY

We searched the Cochrane ENT Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, current issue), Medline (1950 - 2007), PubMed 2007 - 2008, EMBASE (1974 onwards) and other relevant databases. The date of the most recent search was June 2008.

SELECTION CRITERIA

Two authors scrutinized all possible citations to identify randomised controlled trials in which antiviral agents alone or in combination with other therapies (using different routes of administration and dosage schemes) were given as treatment for Ramsay Hunt syndrome. We contacted an author for further information.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility and trial quality.

MAIN RESULTS

Only one randomised, controlled trial was identified and included. It was of low quality and included only 15 participants. In this 1992 trial, intravenous acyclovir and corticosteroids were compared with corticosteroids alone. Our analysis found no statistically significant difference between the two groups.

AUTHORS' CONCLUSIONS

We found no evidence that anti-viral agents have a beneficial effect on outcomes in Ramsay Hunt syndrome, despite their widespread use in this condition. The use of these drugs in patients with herpes zoster infections in other parts of the body might suggest that they have a role in herpes zoster oticus. As usual, the absence of positive evidence of benefit (or, in this case, the 'negative' result of one small, statistically under-powered study) does not necessarily indicate that antivirals are ineffective. However, these drugs are associated with a number of adverse effects and this must be taken into consideration when undertaking the requisite risk-benefit analysis before instigating treatment.

Stem cell treatment for acute myocardial infarction

BACKGROUND

Stem cell therapy offers a promising approach to the regeneration of damaged vascular and cardiac tissue after myocardial infarction (MI). This has resulted in multiple randomised controlled trials (RCTs) worldwide.

OBJECTIVES

To critically evaluate evidence from RCTs on the effectiveness of adult bone marrow-derived stem cells (BMSC) to treat acute MI.

SEARCH STRATEGY

MEDLINE (1950 to August 2007), EMBASE (1974 to August 2007), The Cochrane Library (Issue 3 2007), and CINAHL (1982 to August 2007) were searched. In addition LILACS, KOREAMED, INMED, Current Controlled Trials Register, the UK National Research Register and other handsearching was undertaken to August 2007.

SELECTION CRITERIA

RCTs comparing autologous stem/progenitor cells with no autologous stem/progenitor cells in patients diagnosed with acute myocardial infarction (AMI) were eligible.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened all references, assessed trial quality and extracted data. Meta-analyses using a random-effects model were conducted and heterogeneity was explored using sub-group analyses.

MAIN RESULTS

Thirteen RCTs (811 participants) were included. There were insufficient events on clinical outcomes like mortality to draw clear conclusions. Stem/progenitor cell treatment does not appear to be associated with an increase in adverse events but again the data do not allow clear conclusions. Left ventricular ejection fraction (LVEF) was the outcome with most results and there was marked heterogeneity between trials. There was however a consistent pattern indicating that BMSC treatment generally improves short-term LVEF, with similar trends for left ventricular end systolic and end diastolic volumes (LVESV and LVEDV), infarct size or cardiac wall motion. There was a positive correlation between cell dose infused and the effect on LVEF measured by magnetic resonance imaging.

AUTHORS' CONCLUSIONS

The results of this systematic review suggest that there is little evidence to assess the clinical effects of this treatment. Larger trials using optimal dosing and more reliable, patient-centred outcomes are required. Several trials are ongoing but is unclear whether these will overcome the limitations of the current evidence base.

The Cochrane Ear, Nose and Throat Disorders Group

The Cochrane Ear, Nose and Throat Disorders Group is part of The Cochrane Collaboration and produces high-quality systematic reviews of interventions in otolaryngology and a register of all published and unpublished randomized and controlled trials in otolaryngology-head and neck surgery. The editorial base in Oxford provides support for volunteer reviewers who are practitioners, epidemiologists, or patients wishing to undertake reviews, and these are published in The Cochrane Library (www.thecochranelibrary.com). Participation and group membership is free and open to all. We describe here how the group is organized, how it undertakes its core activities, and how you, the reader, can become involved.