Hydroxyurea for sickle cell disease

Hydroxyurea (hydroxycarbamide) for sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is one of the most common inherited diseases worldwide. It is associated with lifelong morbidity and a reduced life expectancy. Hydroxyurea (hydroxycarbamide), an oral chemotherapeutic drug, ameliorates some of the clinical problems of SCD, in particular that of pain, by raising foetal haemoglobin (HbF). This is an update of a previously published Cochrane Review.

OBJECTIVES

The aims of this review are to determine through a review of randomised or quasi-randomised studies whether the use of hydroxyurea in people with SCD alters the pattern of acute events, including pain; prevents, delays or reverses organ dysfunction; alters mortality and quality of life; or is associated with adverse effects. In addition, we hoped to assess whether the response to hydroxyurea in SCD varies with the type of SCD, age of the individual, duration and dose of treatment, and healthcare setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries. The date of the most recent search was 17 February 2022.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials (RCTs and quasi-RCTs), of one month or longer, comparing hydroxyurea with placebo or standard therapy in people  with SCD.

DATA COLLECTION AND ANALYSIS

Authors independently assessed studies for inclusion, carried out data extraction, assessed the risk of bias and assessed the quality of the evidence using GRADE.

MAIN RESULTS

We included nine RCTs recruiting 1104 adults and children with SCD (haemoglobin SS (HbSS), haemoglobin SC (HbSC) or haemoglobin Sβºthalassaemia (HbSβºthal) genotypes). Studies lasted from six to 30 months. We judged the quality of the evidence for the first two comparisons below as moderate to low as the studies contributing to these comparisons were mostly large and well-designed (and at low risk of bias); however, the evidence was limited and imprecise for some outcomes such as quality of life, deaths during the studies and adverse events, and the results are applicable only to individuals with HbSS and HbSβºthal genotypes. We judged the quality of the evidence for the third and fourth comparisons to be very low due to the limited number of participants, the lack of statistical power (both studies were terminated early with approximately only 20% of their target sample size recruited) and the lack of applicability to all age groups and genotypes. Hydroxyurea versus placebo Five studies (784 adults and children with HbSS or HbSβºthal) compared hydroxyurea to placebo; four recruited individuals with only severe disease and one recruited individuals with all disease severities. Hydroxyurea probably improves pain alteration (using measures such as pain crisis frequency, duration, intensity, hospital admissions and opoid use) and life-threatening illness, but we found no difference in death rates (10 deaths occurred during the studies, but the rates did not differ by treatment group) (all moderate-quality evidence). Hydroxyurea may improve measures of HbF (low-quality evidence) and probably decreases neutrophil counts (moderate-quality evidence). There were no consistent differences in terms of quality of life and adverse events (including serious or life-threatening events) (low-quality evidence). There were fewer occurrences of acute chest syndrome and blood transfusions in the hydroxyurea groups.  Hydroxyurea and phlebotomy versus transfusion and chelation Two studies (254 children with HbSS or HbSβºthal also with risk of primary or secondary stroke) contributed to this comparison. There were no consistent differences in terms of pain alteration, death or adverse events (low-quality evidence) or life-threatening illness (moderate-quality evidence). Hydroxyurea with phlebotomy probably increased HbF and decreased neutrophil counts (moderate-quality evidence), but there were more occurrences of acute chest syndrome and infections. Quality of life was not reported. In the primary prevention study, no strokes occurred in either treatment group but in the secondary prevention study, seven strokes occurred in the hydroxyurea and phlebotomy group (none in the transfusion and chelation group) and the study was terminated early.  Hydroxyurea versus observation One study (22 children with HbSS or HbSβºthal also at risk of stoke) compared hydroxyurea to observation. Pain alteration and quality of life were not reported. There were no differences in life-threatening illness, death (no deaths reported in either group) or adverse events (very low-quality evidence). We are uncertain if hydroxyurea improves HbF or decreases neutrophil counts (very low-quality evidence). Treatment regimens with and without hydroxyurea One study (44 adults and children with HbSC) compared treatment regimens with and without hydroxyurea. Pain alteration, life-threatening illness and quality of life were not reported. There were no differences in death rates (no deaths reported in either group), adverse events or neutrophil levels (very low-quality evidence). We are uncertain if hydroxyurea improves HbF (very low-quality evidence).

AUTHORS' CONCLUSIONS

There is evidence to suggest that hydroxyurea may be effective in decreasing the frequency of pain episodes and other acute complications in adults and children with sickle cell anaemia of HbSS or HbSβºthal genotypes and in preventing life-threatening neurological events in those with sickle cell anaemia at risk of primary stroke by maintaining transcranial Doppler velocities. However, there is still insufficient evidence on the long-term benefits of hydroxyurea, particularly with regard to preventing chronic complications of SCD, or recommending a standard dose or dose escalation to maximum tolerated dose. There is also insufficient evidence about the long-term risks of hydroxyurea, including its effects on fertility and reproduction. Evidence is also limited on the effects of hydroxyurea on individuals with the HbSC genotype. Future studies should be designed to address such uncertainties.

The Evolving Pharmacotherapeutic Landscape for the Treatment of Sickle Cell Disease

Sickle cell disease (SCD) is an extremely heterogeneous disease that has been associated with global morbidity and early mortality. More effective and inexpensive therapies are needed. During the last five years, the landscape of the pharmacotherapy of SCD has changed dramatically. Currently, 54 drugs have been used or under consideration to use for the treatment of SCD. These fall into 3 categories: the first category includes the four drugs (Hydroxyurea, L-Glutamine, Crizanlizumab tmca and Voxelotor) that have been approved by the United States Food and Drug Administration (FDA) based on successful clinical trials. The second category includes 22 drugs that failed, discontinued or terminated for now and the third category includes 28 drugs that are actively being considered for the treatment of SCD. Crizanlizumab and Voxelotor are included in the first and third categories because they have been used in more than one trial. New therapies targeting multiple pathways in the complex pathophysiology of SCD have been achieved or are under continued investigation. The emerging trend seems to be the use of multimodal drugs (i.e. drugs that have different mechanisms of action) to treat SCD similar to the use of multiple chemotherapeutic agents to treat cancer.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register. We also searched online trials registries for any ongoing trials (01 July 2018).Last search of the Group's Haemoglobinopathies Trials Register: 08 October 2018.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 51 studies identified, three met the inclusion criteria, including 524 people with sickle cell disease aged between 12 and 65 years of age. One study tested the effectiveness of zinc sulphate as compared to placebo and the remaining two assessed senicapoc versus placebo. No deaths were seen in any of the studies (low-quality evidence). The zinc sulphate study showed a significant reduction in painful crises (in a total of 145 participants) over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15) (moderate-quality evidence). However, analysis was restricted due to limited statistical data. Changes to red blood cell parameters and blood counts were inconsistent (very low-quality evidence). No serious adverse events were noted in the study. The Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo showed that the high dose senicapoc showed significant improvement in change in hemoglobin level, the number and proportion of dense red blood cells, red blood cell count and indices and hematocrit value (very low-quality evidence). The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups (low-quality evidence). A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red blood cell survival (depending on dose), this did not lead to fewer painful crises.Given this is no longer an active area of research, this review will no longer be regularly updated.

Red blood cell transfusion to treat or prevent complications in sickle cell disease: an overview of Cochrane reviews

BACKGROUND

Globally, sickle cell disease (SCD) is one of the commonest severe monogenic disorders, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Red blood cell (RBC) transfusions are used to treat complications of SCD, e.g. acute chest syndrome (ACS) (this often involves a single transfusion episode), or they can be part of a regular long-term transfusion programme to prevent SCD complications.

OBJECTIVES

To summarize the evidence in Cochrane Reviews of the effectiveness and safety of RBC transfusions versus no transfusion, or restrictive (to increase the total haemoglobin) versus liberal (to decrease the haemoglobin S level below a specified percentage) transfusion, for treating or preventing complications experienced by people with SCD.

METHODS

We included Cochrane Reviews of randomised or quasi-randomised controlled trials published in the Cochrane Database of Systematic Reviews, that addressed various SCD complications and had RBC transfusion as an intervention or comparator. We assessed the methodological quality of included reviews according to the AMSTAR quality assessment.

MAIN RESULTS

We included 15 Cochrane Reviews, 10 of which had no included studies with an RBC transfusion intervention (five reported RCTs with other interventions; and five contained no studies). Five of the 15 reviews included participants randomised to RBC transfusion, but in one of these reviews only 10 participants were randomised with no usable data. Four reviews (nine trials with 1502 participants) reported data comparing short- or long-term RBC transfusions versus standard care, disease-modifying agents, a restrictive versus a liberal transfusion strategy and long-term RBC transfusions versus transfusions to treat complications. All reviews were of high quality according to AMSTAR quality assessment, however, the quality of the included trials was highly variable across outcomes. Trials were downgraded according to GRADE methodology for risk of bias, indirectness (most trials were conducted in children with HbSS), and imprecision (outcomes had wide confidence intervals).In all four reviews and all comparisons there was little or no difference in the risk of death (very low-quality evidence). There were either no deaths or death was a rare event.Short-term RBC transfusion versus standard care (one review: two trials, 434 participants, GRADE very low- to low-quality evidence)In people undergoing low- to medium-risk surgery, RBC transfusions may decrease the risk of acute chest syndrome (ACS) in people with African haplotypes compared to standard care (low-quality evidence), but there was little or no difference in people with the Arabic haplotype (very-low quality evidence). There was also little or no difference in the risk of other SCD-related or transfusion-related complications (very-low quality evidence).Long-term RBC transfusion versus standard care (two reviews: three trials, 405 participants, very low- to moderate-quality evidence)In children and adolescents at high risk of stroke (abnormal transcranial doppler (TCD) velocities or silent cerebral infarct (SCI)), long-term RBC transfusions probably decrease the risk of stroke (moderate-quality evidence) and may decrease the risk of ACS and painful crisis compared to standard care (low-quality evidence). Long-term RBC transfusions may also decrease the risk of SCI in children with abnormal TCD velocities (low-quality evidence), but there may be little or no difference in the risk of SCI in children with normal TCD velocities and previous SCI (low-quality evidence).In children and adolescents already receiving long-term RBC transfusions for preventing stroke, in comparison to standard care, continuing long-term RBC transfusions may reduce the risk of SCI (low-quality evidence) but we do not know whether there is a difference in the risk of stroke (very-low quality evidence). In children with normal TCD velocities and SCI there was little or no difference in the risk of alloimmunisation or transfusion reactions, but RBC transfusions may increase the risk of iron overload (low-quality evidence).Long-term RBC transfusion versus RBC transfusion to treat complications (one review: one trial, 72 participants, very low- to low-quality evidence)In pregnant women, long-term RBC transfusions may decrease the risk of painful crisis compared to transfusion for complications (low-quality evidence); but there may be little or no difference in the risk of other SCD-related complications or transfusion reactions (very-low quality evidence).RBC transfusion versus disease-modifying agents (hydroxyurea) (two reviews: two trials; 254 participants, very low- to low-quality evidence)For primary prevention of stroke in children, with abnormal TCD and no severe vasculopathy on magnetic resonance imaging/magnetic resonance angiography (MRI/MRA), who have received at least one year of RBC transfusions, we do not know whether there is a difference between RBC transfusion and disease-modifying agents in the risk of stroke; SCI; ACS; or painful crisis (very-low quality evidence). There may be little or no difference in the risk of iron overload (low-quality evidence).Similarly, for secondary prevention of stroke in children and adolescents, we do not know whether there is a difference between these interventions in the risk of stroke; SCI; or ACS (very-low quality evidence); but hydroxyurea with phlebotomy may increase the risk of painful crisis and global SCD serious adverse events compared to RBC transfusion (low-quality evidence). There may be little or no difference in the risk of iron overload (low-quality evidence).Restrictive versus liberal RBC transfusion strategy (one review: one trial; 230 participants, very low-quality evidence)In people undergoing cholecystectomy, there was little or no difference between strategies in the risk of SCD-related or transfusion-related complications (very-low quality evidence).

AUTHORS' CONCLUSIONS

This overview provides support from two high-quality Cochrane Reviews for the use of RBC transfusions in preventing stroke in children and adolescents at high risk of stroke (abnormal TCDs or SCI) and evidence that it may decrease the risk of SCI in children with abnormal TCD velocities. In addition RBC transfusions may reduce the risk of ACS and painful crisis in this population.This overview highlights the lack of high-quality evidence in adults with SCD and the number of reviews that have no evidence for the use of RBC transfusions across a spectrum of SCD complications. Also of concern is the variable and often incomplete reporting of patient-relevant outcomes in the included trials such as SCD-related serious adverse events and quality of life.

Hydroxyurea (hydroxycarbamide) for sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is one of the most common inherited diseases worldwide. It is associated with lifelong morbidity and a reduced life expectancy. Hydroxyurea (hydroxycarbamide), an oral chemotherapeutic drug, ameliorates some of the clinical problems of SCD, in particular that of pain, by raising fetal haemoglobin. This is an update of a previously published Cochrane Review.

OBJECTIVES

To assess the effects of hydroxyurea therapy in people with SCD (all genotypes), of any age, regardless of setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Register, comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries.Date of the most recent search: 16 January 2017.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials, of one month or longer, comparing hydroxyurea with placebo, standard therapy or other interventions for people with SCD.

DATA COLLECTION AND ANALYSIS

Authors independently assessed studies for inclusion, carried out data extraction and assessed the risk of bias.

MAIN RESULTS

Seventeen studies were identified in the searches; eight randomised controlled trials were included, recruiting 899 adults and children with SCD (haemoglobin SS (HbSS), haemoglobin SC (HbSC) or haemoglobin Sβºthalassaemia (HbSβºthal) genotypes). Studies lasted from six to 30 months.Four studies (577 adults and children with HbSS or HbSβºthal) compared hydroxyurea to placebo; three recruited individuals with only severe disease and one recruited individuals with all disease severities. There were statistically significant improvements in terms of pain alteration (using measures such as pain crisis frequency, duration, intensity, hospital admissions and opoid use), measures of fetal haemoglobin and neutrophil counts and fewer occurrences of acute chest syndrome and blood transfusions in the hydroxyurea groups. There were no consistent statistically significant differences in terms of quality of life and adverse events (including serious or life-threatening events). Seven deaths occurred during the studies, but the rates by treatment group were not statistically significantly different.Two studies (254 children with HbSS or HbSβºthal also with risk of primary or secondary stroke) compared hydroxyurea and phlebotomy to transfusion and chelation; there were statistically significant improvements in terms of measures of fetal haemoglobin and neutrophil counts, but more occurrences of acute chest syndrome and infections in the hydroxyurea and phlebotomy group. There were no consistent statistically significant differences in terms of pain alteration and adverse events (including serious or life-threatening events). Two deaths occurred during the studies (one in a the hydroxyurea treatment arm and one in the control arm), but the rates by treatment group were not statistically significantly different. In the primary prevention study, no strokes occurred in either treatment group but in the secondary prevention study, seven strokes occurred in the hydroxyurea and phlebotomy group (none in the transfusion and chelation group) and the study was terminated early.The quality of the evidence for the above two comparisons was judged as moderate to low as the studies contributing to these comparisons were mostly large and well designed (and at low risk of bias); however evidence was limited and imprecise for some outcomes such as quality of life, deaths during the studies and adverse events and results are applicable only to individuals with HbSS and HbSβºthal genotypes.Of the remaining two studies, one (22 children with HbSS or HbSβºthal also at risk of stoke) compared hydroxyurea to observation; there were statistically significant improvements in terms of measures of fetal haemoglobin and neutrophil counts but no statistically significant differences in terms of adverse events (including serious or life-threatening events).The final study (44 adults and children with HbSC) compared treatment regimens with and without hydroxyurea - there was statistically significant improvement in terms of measures of fetal haemoglobin, but no statistically significant differences in terms of adverse events (including serious or life-threatening events). No participants died in either of these studies and other outcomes relevant to the review were not reported.The quality of the evidence for the above two comparisons was judged to be very low due to the limited number of participants, the lack of statistical power (as both studies were terminated early with approximately only 20% of their target sample size recruited) and the lack of applicability to all age groups and genotypes.

AUTHORS' CONCLUSIONS

There is evidence to suggest that hydroxyurea is effective in decreasing the frequency of pain episodes and other acute complications in adults and children with sickle cell anaemia of HbSS or HbSβºthal genotypes and in preventing life-threatening neurological events in those with sickle cell anaemia at risk of primary stroke by maintaining transcranial doppler velocities. However, there is still insufficient evidence on the long-term benefits of hydroxyurea, particularly in preventing chronic complications of SCD, recommending a standard dose or dose escalation to maximum tolerated dose. There is also insufficient evidence about the long-term risks of hydroxyurea, including its effects on fertility and reproduction. Evidence is also limited on the effects of hydroxyurea on individuals with HbSC genotype. Future studies should be designed to address such uncertainties.

Hydroxyurea therapy in adult Nigerian sickle cell disease: a monocentric survey on pattern of use, clinical effects and patient's compliance

BACKGROUND

The clinical prospects of hydroxyurea therapy in the management of sickle cell disease (SCD) require evaluation in the Nigerian setting to develop indigenous guidelines. This survey examines the pattern of hydroxyurea therapy, its clinico-haematologic benefits and safety profile in Nigerian SCD subjects.

METHODS

A cross sectional pilot survey was carried out among 60 adult SCD subjects over 3 months. Data on clinical phenotypes, relevant haematological parameters and details of hydroxyurea therapy were obtained using a structured questionnaire through an interview process and case file review.

RESULTS

The median age was 30 years. Thirty-four (56.7%) of the subjects are aware of hydroxyurea therapy in SCD. Twenty-four (40%) SCD patients had previously used hydroxyurea. Only 4 subjects were fully compliant. Reasons for non-compliance included poor knowledge and lack of funds. In particular, hydroxyurea reduced leucocyte count and increased mean red cell volume (MCV) in compliant subjects.

CONCLUSION

Hydroxyurea use is low among Nigerian SCD subjects despite its proven efficacy/clinical prospects in the developed nations. Large scale multicenter studies and clinical trials are needed to form a basis for developing standard local treatment protocol for its use.

Hydroxyurea for reducing blood transfusion in non-transfusion dependent beta thalassaemias

BACKGROUND

Non-transfusion dependent beta thalassaemia is a subset of inherited haemoglobin disorders characterised by reduced production of the beta globin chain of the haemoglobin molecule leading to anaemia of varying severity. Although blood transfusion is not a necessity for survival, it is required when episodes of chronic anaemia occur. This chronic anaemia can impair growth and affect quality of life. People with non-transfusion dependent beta thalassaemia suffer from iron overload due to their body's increased capability of absorbing iron from food sources. Iron overload becomes more pronounced in those requiring blood transfusion. People with a higher foetal haemoglobin level have been found to require fewer blood transfusions. Hydroxyurea has been used to increase foetal haemoglobin level; however, its efficacy in reducing transfusion, chronic anaemia complications and its safety need to be established.

OBJECTIVES

To assess the effectiveness, safety and appropriate dose regimen of hydroxyurea in people with non-transfusion dependent beta thalassaemia (haemoglobin E combined with beta thalassaemia and beta thalassaemia intermedia).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of relevant journals. We also searched ongoing trials registries and the reference lists of relevant articles and reviews.Date of last search: 30 April 2016.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of hydroxyurea in people with non-transfusion dependent beta thalassaemia comparing hydroxyurea with placebo or standard treatment or comparing different doses of hydroxyurea.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the inclusion criteria in order to select trials for inclusion. Both authors assessed the risk of bias of trials and extracted the data. A third author verified these assessments.

MAIN RESULTS

No trials comparing hydroxyurea with placebo or standard care were found. However, we included one randomised controlled trial (n = 61) comparing 20 mg/kg/day with 10 mg/kg/day of hydroxyurea for 24 weeks.Both haemoglobin and foetal haemoglobin levels were lower at 24 weeks in the 20 mg group compared with the 10 mg group, mean difference -2.39 (95% confidence interval - 2.8 to -1.98) and mean difference -1.5 (95% confidence interval -1.83 to -1.17), respectively. Major adverse effects were significantly more common in the 20 mg group, for neutropenia risk ratio 9.93 (95% confidence interval 1.34 to 73.97) and for thrombocytopenia risk ratio 3.68 (95% confidence interval 1.13 to 12.07). No difference was reported for minor adverse effects (gastrointestinal disturbances and raised liver enzymes). The effect of hydroxyurea on transfusion frequency was not reported.The overall quality for the outcomes reported was graded as very low mainly because the outcomes were derived from only one small study with an unclear method of allocation concealment.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials to show whether hydroxyurea has any effect compared with controls on the need for blood transfusion. Administration of 10 mg/kg/day compared to 20 mg/kg/day of hydroxyurea resulted in higher haemoglobin levels and seems safer with fewer adverse effects. It has not been reported whether hydroxyurea is capable of reducing the need for blood transfusion. Large well-designed randomised controlled trials with sufficient duration of follow up are recommended.

Hematopoietic stem cell transplantation for people with sickle cell disease

BACKGROUND

Sickle cell disease is a genetic disorder involving a defect in the red blood cells due to its sickled hemoglobin. The main therapeutic interventions include preventive and supportive measures. Hematopoietic stem cell transplantations are carried out with the aim of replacing the defective cells and their progenitors (hematopoietic (i.e. blood forming) stem cells) in order to correct the disorder. This is an update of a previously published review.

OBJECTIVES

To determine whether stem cell transplantation can improve survival and prevent symptoms and complications associated with sickle cell disease. To examine the risks of stem cell transplantation against the potential long-term gain for people with sickle cell disease.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Group's Haemoglobinopathies Trials Register complied from electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (updated each new issue of The Cochrane Library) and quarterly searches of MEDLINE.Unpublished work was identified by searching the abstract books of major conference proceedings and we conducted a search of the website: www.ClinicalTrials.gov.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 06 October 2015.

SELECTION CRITERIA

Randomized controlled and quasi-randomized studies that compared any method of stem cell transplantation with either each other or with any of the preventive or supportive interventions (e.g. periodic blood transfusion, use of hydroxyurea, antibiotics, pain relievers, supplemental oxygen) in people with sickle cell disease irrespective of the type of sickle cell disease, gender and setting.

DATA COLLECTION AND ANALYSIS

No relevant trials were identified.

MAIN RESULTS

Ten trials were identified by the initial search and none for the update. None of these trials were suitable for inclusion in this review.

AUTHORS' CONCLUSIONS

Reports on the use of hematopoietic stem cell transplantation improving survival and preventing symptoms and complications associated with sickle cell disease are currently limited to observational and other less robust studies. No randomized controlled trial assessing the benefit or risk of hematopoietic stem cell transplantations was found. Thus, this systematic review identifies the need for a multicentre randomized controlled trial assessing the benefits and possible risks of hematopoietic stem cell transplantations comparing sickle status and severity of disease in people with sickle cell disease.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 28 November 2015.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.We will continue to run searches to identify any potentially relevant trials; however, we do not plan to update other sections of the review until new trials are published.

Piracetam for reducing the incidence of painful sickle cell disease crises

BACKGROUND

Sickle cell disease is one of the most common genetic disorders. Sickle cell crises in which irregular and dehydrated cells contribute to blocking of blood vessels are characterised by episodes of pain. Treatment is mainly supportive and symptomatic. In vitro studies with piracetam indicate that it has the potential for inhibition and a reversal of the process of sickling of erythrocytes. This is an update of a previously published Cochrane review.

OBJECTIVES

To assess the effectiveness of piracetam for reducing the incidence of painful sickle cell disease crises.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Last search of the Group's Haemoglobinopathies Trials Register: 21 September 2015.

SELECTION CRITERIA

Randomised controlled trials comparing orally administered piracetam to placebo or standard care in people, of all ages and both sexes, with sickle cell disease.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Trial authors were contacted for additional information. Adverse effects data were collected from the trials.

MAIN RESULTS

Three trials involving 169 participants were included in the review. A limited amount of data addressing some of the primary and some of the secondary outcomes were provided, but data were incomplete and based on un-validated assumptions used in the evaluation of outcomes. One trial reported a reduction in the number of pain crises and their severity with active intervention than placebo but presented no data to confirm these results. A second trial presented a monthly global pain score based on the number of sickle cell crises and severity of pain but included no separate data for these primary outcomes. Although there was no significant difference between the piracetam and placebo periods for the number of days of hospitalisation (P = 0.87) in one trial, inconsistencies in the criteria necessary for hospitalisation during sickle crises did not permit accurate conclusions to be drawn. Two of the trials reported participant satisfaction with piracetam but provided no details as to how this satisfaction had been assessed. There were no reports of toxicity or adverse effects with piracetam other than one participant who experienced dizziness.

AUTHORS' CONCLUSIONS

The small number of included trials and their poor methodological quality provided insufficient reliable evidence to support the routine use of this medication for preventing the incidence of painful sickle cell disease crises.We will continue to run searches to identify any potentially relevant trials; however, we do not plan to update other sections of the review until new trials are published.

Phytomedicines (medicines derived from plants) for sickle cell disease

BACKGROUND

Sickle cell disease, a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbean and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. There has been little systematic appraisal of their benefits. This is an update of a Cochrane Review first published in 2010 and updated in 2013.

OBJECTIVES

To assess the benefits and risks of phytomedicines in people with sickle cell disease of all types, of any age, in any setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, the International Standard Randomised Controlled Trial Number Register (ISRCTN) and the Allied and Complimentary Medicine Database (AMED).Dates of most recent searches: Haemoglobinopathies Trials Register: 13 October 2014;

ISRCTN

17 January 2015; AMED: 20 January 2015.

SELECTION CRITERIA

Randomised or quasi-randomised trials with participants of all ages with sickle cell disease, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data.

MAIN RESULTS

Two trials (182 participants) and two phytomedicines Niprisan(®) (also known as Nicosan(®)) and Ciklavit(®) were included. The Phase IIB (pivotal) trial suggests that Niprisan(®) was effective in reducing episodes of severe painful sickle cell disease crisis over a six-month period. It did not affect the risk of severe complications or the level of anaemia. No serious adverse effects were reported. The single trial of Cajanus cajan (Ciklavit(®)) reported a possible benefit to individuals with painful crises, and a possible adverse effect (non-significant) on the level of anaemia.

AUTHORS' CONCLUSIONS

While Niprisan(®) appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in the management of people with sickle cell disease and the results of its multicentre trials are awaited. Currently no conclusions can be made regarding the efficacy of Ciklavit(®). Based on the published results for Niprisan(®) and in view of the limitations in data collection and analysis of both trials, phytomedicines may have a potential beneficial effect in reducing painful crises in sickle cell disease. This needs to be further validated in future trials. More trials are required on the safety and efficacy of phytomedicines used in managing sickle cell disease.

Hematopoietic stem cell transplantation for people with sickle cell disease

BACKGROUND

Sickle cell disease is a genetic disorder involving a defect in the red blood cells due to its sickled hemoglobin. The main therapeutic interventions include preventive and supportive measures. Hematopoietic stem cell transplantations are carried out with the aim of replacing the defective cells and their progenitors (hematopoietic (i.e. blood forming) stem cells) in order to correct the disorder.

OBJECTIVES

To determine whether stem cell transplantation can improve survival and prevent symptoms and complications associated with sickle cell disease. To examine the risks of stem cell transplantation against the potential long-term gain for people with sickle cell disease.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Group's Haemoglobinopathies Trials Register complied from electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (updated each new issue of The Cochrane Library) and quarterly searches of MEDLINE.Unpublished work was identified by searching the abstract books of major conference proceedings and we conducted a search of the website: www.ClinicalTrials.gov.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 16 August 2012.

SELECTION CRITERIA

Randomized controlled and quasi-randomized studies that compared any method of stem cell transplantation with either each other or with any of the preventive or supportive interventions (e.g. periodic blood transfusion, use of hydroxyurea, antibiotics, pain relievers, supplemental oxygen) in people with sickle cell disease irrespective of the type of sickle cell disease, gender and setting.

DATA COLLECTION AND ANALYSIS

No relevant trials were identified.

MAIN RESULTS

Ten trials were identified by the initial search and none for the update. None of these trials were suitable for inclusion in this review.

AUTHORS' CONCLUSIONS

Reports on the use of hematopoietic stem cell transplantation improving survival and preventing symptoms and complications associated with sickle cell disease are currently limited to observational and other less robust studies. No randomized controlled trial assessing the benefit or risk of hematopoietic stem cell transplantations was found. Thus, this systematic review identifies the need for a multicentre randomized controlled trial assessing the benefits and possible risks of hematopoietic stem cell transplantations comparing sickle status and severity of disease in people with sickle cell disease.

Barriers to hematopoietic cell transplantation clinical trial participation of african american and black youth with sickle cell disease and their parents

African Americans and Blacks have low participation rates in clinical trials and reduced access to aggressive medical therapies. Hematopoietic cell transplantation (HCT) is a high-risk but potentially curative therapy for sickle cell disease (SCD), a disorder predominantly seen in African Americans. We conducted focus groups to better understand participation barriers to HCT clinical trials for SCD. Nine focus groups of youth with SCD (n=10) and parents (n=41) were conducted at 3 sites representing the Midwest, South Atlantic, and West South Central US. Main barriers to clinical trial participation included gaps in knowledge about SCD, limited access to SCD/HCT trial information, and mistrust of medical professionals. For education about SCD/HCT trials, participants highly preferred one-on-one interactions with medical professionals and electronic media as a supplement. Providers can engage with sickle cell camps to provide information on SCD/HCT clinical trials to youth and local health fairs for parents/families. Youth reported learning about SCD through computer games; investigators may find this medium useful for clinical trial/HCT education. African Americans affected by SCD face unique barriers to clinical trial participation and have unmet HCT clinical studies education needs. Greater recognition of these barriers will allow targeted interventions in this community to increase their access to HCT.

Phytomedicines (medicines derived from plants) for sickle cell disease

BACKGROUND

Sickle cell disease (SCD), a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbean and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. There has been little systematic appraisal of their benefits.

OBJECTIVES

To assess the benefits and risks of phytomedicines in people with SCD of all types, of any age, in any setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, the International Standard Randomised Controlled Trial Number Register (ISRCTN) and the Allied and Complimentary Medicine Database (AMED).Dates of most recent searches:Haemoglobinopathies Trials Register: 05 July 2012;ISRCTN: 28 December 2009;AMED: August 2003.

SELECTION CRITERIA

Randomised or quasi-randomised trials with participants of all ages with SCD, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data.

MAIN RESULTS

Two trials (182 participants) and two phytomedicines Niprisan(®) (also known as Nicosan(®)) and Ciklavit(®) were included. The Phase IIB (pivotal) trial suggests that Niprisan(®) was effective in reducing episodes of severe painful SCD crisis over a six-month period. It did not affect the risk of severe complications or the level of anaemia. No serious adverse effects were reported. The single trial of Cajanus cajan (Ciklavit(®)) reported a possible benefit to individuals with painful crises, and a possible adverse effect (non-significant) on the level of anaemia.

AUTHORS' CONCLUSIONS

While Niprisan(®) appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in the management of people with SCD and the results of its multicentre trials are awaited. Currently no conclusions can be made regarding the efficacy of Ciklavit(®). Based on the published results for Niprisan(®) and in view of the limitations in data collection and analysis of both trials, phytomedicines may have a potential beneficial effect in reducing painful crises in SCD. This needs to be further validated in future trials. More trials are required on the safety and efficacy of phytomedicines used in managing SCD.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 25 October 2011.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.

Phytomedicines (medicines derived from plants) for sickle cell disease

BACKGROUND

Sickle cell disease (SCD), a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbeans and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. There has been little systematic appraisal of their benefits.

OBJECTIVES

To assess the benefits and risks of phytomedicines in people with SCD of all types, of any age, in any setting.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register and the ISRCTN Register for all publication years; AMED was searched by the previous authors for an earlier version of this review for the period 1985 to August 2003.Dates of most recent searches:Haemoglobinopathies Trials Register: 07 July 2010;ISRCTN: 28 December 2009;AMED: August 2003.

SELECTION CRITERIA

Randomised or quasi-randomised trials with participants of all ages with SCD, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data.

MAIN RESULTS

Two trials (182 participants) and two phytomedicines Niprisan(®) (also known as Nicosan(®)) and Ciklavit(®)) were included. The Phase IIB (pivotal) trial suggests that Niprisan(®) was effective in reducing episodes of severe painful SCD crisis over a six-month period. It did not affect the risk of severe complications or the level of anaemia. No serious adverse effects were reported. The single trial of Cajanus cajan (Ciklavit(®)) reported a possible benefit to individuals with painful crises, and a possible adverse effect (non-significant) on the level of anaemia.

AUTHORS' CONCLUSIONS

While Niprisan(®) appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in the management of people with SCD and the results of its multicentre trials are awaited. Currently no conclusions can be made regarding the efficacy of Ciklavit(®). Based on the published results for Niprisan(®) and in view of the limitations in data collection and analysis of both trials, phytomedicines may have a potential beneficial effect in reducing painful crises in SCD. This needs to be further validated in future trials. More trials are required on the safety and efficacy of phytomedicines in managing SCD.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs.

OBJECTIVES

To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 22 May 2009.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

Of the 47 studies identified, two met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study had to be stopped prematurely due to lack of reduction in the number of painful crisis.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicentre studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.Though the phase II study of senicapoc showed that the drug improved red cell survival, depending on dose, this did not lead to fewer painful crises; a subsequent phase III study was terminated prematurely for this reason.

Hematopoietic stem cell transplantation for children with sickle cell disease

BACKGROUND

Sickle cell disease is a genetic disorder involving a defect in the red blood cells due to its sickled hemoglobin. The main therapeutic interventions include preventive and supportive measures. Hematopoietic stem cell transplantations are carried out with the aim of replacing the defective cells and their progenitors (hematopoietic (i.e. blood forming) stem cells) in order to correct the disorder.

OBJECTIVES

To determine whether stem cell transplantation can improve survival and prevent symptoms and complications associated with sickle cell disease. To examine the risks of stem cell transplantation against the potential long-term gain for people with sickle cell disease.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Group's Haemoglobinopathies Trials Register complied from electronic searches of the Cochrane Central Register of Controlled Trials (Clinical Trials) (updated each new issue of The Cochrane Library) and quarterly searches of MEDLINE.Unpublished work was identified by searching the abstract books of major conference proceedings and we conducted a search of the website: www.ClinicalTrials.gov.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: September 2008.

SELECTION CRITERIA

Randomized controlled and quasi-randomized studies that compared any method of stem cell transplantation with either each other or with any of the preventive or supportive interventions (e.g. periodic blood transfusion, use of hydroxyurea, antibiotics, pain relievers, supplemental oxygen) in children under 16 years of age irrespective of the type of sickle cell disease, gender and setting.

DATA COLLECTION AND ANALYSIS

No relevant trials have been identified.

MAIN RESULTS

Ten trials were identified by the initial search of which none were suitable for inclusion in this review.

AUTHORS' CONCLUSIONS

Reports on the use of hematopoietic stem cell transplantation improving survival and preventing symptoms and complications associated with sickle cell disease are currently limited to observational and other less robust studies. No randomized controlled trial has assessed the benefit or risk of different types of hematopoietic stem cell transplantations in children. Thus, this systematic review identifies the need for a multicentre randomized controlled trial assessing the benefits and possible risks of different types of hematopoietic stem cell transplantations comparing sickle status and severity of disease in children.

Drugs for preventing red blood cell dehydration in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited disorder of haemoglobin, which results in abnormal red blood cells. These can deform and cause blockages in blood vessels, leading to acute crises such as pain; stroke and splenic sequestration; and chronic organ and tissue damage. Recently research has begun to focus on therapies which prevent the red blood cells deforming by reducing the loss of water and ions from the cells. However, little is known about the effectiveness and safety of such drugs.

OBJECTIVES

To assess the relative risks and benefits of drugs which aim to prevent sickle cell-related crises by reducing red blood cell dehydration.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of the most recent search of the Group's Haemoglobinopathies Trials Register: November 2006.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of drugs which aim to prevent sickle cell crises by reducing red cell dehydration, compared to placebo or an alternative treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently selected studies for inclusion, assessed study quality and extracted data from the included studies.

MAIN RESULTS

Of the 39 studies identified, one met the inclusion criteria. This study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in the total number of pain, haemolytic, aplastic and sequestration crises over one and a half years, WMD -2.83 (95% CI -3.51 to -2.15). However, our analysis was limited by non-reporting of standard deviations for some data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.

AUTHORS' CONCLUSIONS

While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicentre studies over a number of years are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.

Piracetam for reducing the incidence of painful sickle cell disease crises

BACKGROUND

Sickle cell disease is one of the most common genetic disorders. Sickle cell crises in which irregular and dehydrated cells contribute to blocking of blood vessels are characterised by episodes of pain. Treatment is mainly supportive and symptomatic. In vitro studies with piracetam indicate that it has the potential for inhibition and a reversal of the process of sickling of erythrocytes.

OBJECTIVES

To assess the effectiveness of piracetam for reducing the incidence of painful sickle cell disease crises.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of the last search of the Group's Haemoglobinopathies Trials Register: February 2007.

SELECTION CRITERIA

Randomised controlled trials comparing orally administered piracetam to placebo or standard care in people, of all ages and both sexes, with sickle cell disease.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Trial authors were contacted for additional information. Adverse effects data were collected from the trials.

MAIN RESULTS

Three trials involving 169 participants were included in the review. A limited amount of data addressing some of the primary and some of the secondary outcomes were provided, but data were incomplete and based on unvalidated assumptions used in the evaluation of outcomes. One trial reported a reduction in the number of pain crises and their severity with active intervention than placebo but presented no data to confirm these results. A second trial presented a monthly global pain score based on the number of sickle cell crises and severity of pain but included no separate data for these primary outcomes. Although there was no significant difference between the piracetam and placebo periods for the number of days of hospitalisation (P = 0.87) in one trial, inconsistencies in the criteria necessary for hospitalisation during sickle crises did not permit accurate conclusions to be drawn. Two of the trials reported participant satisfaction with piracetam but provided no details as to how this satisfaction had been assessed. There were no reports of toxicity or adverse effects with piracetam other than one participant who experienced dizziness.

AUTHORS' CONCLUSIONS

The small number of included trials and their poor methodological quality provided insufficient reliable evidence to support the routine use of this medication for preventing the incidence of painful sickle cell disease crises.

Blood transfusion for preventing stroke in people with sickle cell disease

BACKGROUND

Sickle cell disease is a common inherited haemoglobin disorder. The abnormal haemoglobin causes distortion of red blood cells, anaemia, vaso-occlusion and dysfunction in virtually any organ system in the body. Stroke occurs in around 10% of children with sickle cell anaemia, and recurrences after a first stroke are likely. Chronic blood transfusion regimes are often used in an attempt to dilute the sickled red blood cells, thus reducing the risk of vaso-occlusion and stroke. However, the side-effects of such regimens can be severe.

OBJECTIVES

To assess the relative risks and benefits of chronic blood transfusion regimes in patients with sickle cell disease to prevent a first stroke or further strokes.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Date of the most recent search of the Group's specialised register: July 2001

SELECTION CRITERIA

All those randomised or quasi-randomised controlled trials in which blood transfusion as a preventative measure for stroke in patients with sickle cell disease are compared to an alternative treatment or to no treatment.

DATA COLLECTION AND ANALYSIS

Both reviewers independently assessed trial quality and extracted data from the study included.

MAIN RESULTS

One trial was identified by the initial search and this met the inclusion criteria for the review. The trial compared a chronic transfusion regime to maintain sickle haemoglobin at less than 30% with standard care in 130 children with sickle cell disease who were judged to be at high risk of a first stroke through transcranial doppler ultrasonography. Eleven children in the standard care group suffered a stroke during the trial, compared to only one in the transfusion group. Because of this 92% relative risk reduction, the trial was terminated 16 months early. It had been planned that all patients would be treated for 30 months, but median follow-up only 21.1 months. However, a high rate of complications such as iron overload, alloimmunisation and transfusion reactions were seen in the children who were receiving transfusions. No randomised controlled trials were identified which investigated use of transfusion for preventing recurrence of stroke.

REVIEWER'S CONCLUSIONS

While the included study demonstrated a significantly reduced risk of stroke in patients receiving regular blood transfusions, the degree of risk must be balanced against the burden of a chronic transfusion regime. Further research is required to establish the use of transfusion in preventing secondary stroke, the age, or length of time after an event, at which transfusion can safely be stopped, and to further define risk factors for stroke in order to reduce the chance of unnecessarily putting children onto a chronic transfusion regime.