What are liberal studies

Cochrane

Question

The aim was to investigate the benefits and harms of a restrictive erythrocyte transfusion strategy compared to a liberal transfusion strategy in people with blood cancer (e.g. leukemia, lymphoma, myeloma) who received intensive treatments for their disease (chemotherapy or stem cell transplantation).

background

People with blood cancer often have anemia (low hemoglobin levels) due to their cancer or treatment (chemotherapy or stem cell transplant). Hemoglobin is the substance in red blood cells that is responsible for transporting oxygen around the body.

An erythrocyte transfusion is given to increase hemoglobin levels, prevent symptoms of anemia, or treat symptoms of anemia. A decision to have an erythrocyte transfusion should weigh the benefits against the possible risks (e.g. rash, fever, chills, development of breathing problems). These reactions are usually mild and easy to treat. Serious reactions to red blood cell transfusions, however, are extremely rare. In high-income countries, the likelihood of getting an infection from an erythrocyte transfusion is very low, whereas the risk in low-income countries is much higher. The need for an erythrocyte transfusion is usually tied to the hemoglobin level. In people with other illnesses, a transfusion is usually given when the hemoglobin value has dropped to around 70 g / L to 80 g / L (restrictive transfusion strategy). People with blood cancer could benefit from a higher hemoglobin value (100 g / L to 120 g / L, liberal transfusion strategy), as it could reduce the bleeding tendency and improve the quality of life. For those undergoing surgery or those in intensive care units, a restrictive transfusion strategy has proven to be just as safe, or even safer, than a liberal transfusion strategy.

Study characteristics

We looked for randomized trials and prospective, non-randomized trials. Six studies met our inclusion criteria, four are completed, and two are ongoing. Another study is yet to be classified. The completed studies were conducted between 1997 and 2015 and included 240 participants. One study included children who received a stem cell transplant and stopped early due to safety concerns (six children). The other three studies included adults only, of whom 218 received chemotherapy for acute leukemia and 16 with blood cancer received a stem cell transplant. Three studies were randomized controlled studies and the fourth was a non-randomized study. The hemoglobin threshold of the restrictive strategies varied across the studies.

The sources of funding were given in all four studies. One study was industry-funded.

Main results

The evidence is current to June 2016 and mainly includes adults with acute leukemia undergoing chemotherapy.

A restrictive red cell transfusion policy could reduce the total number of red cell transfusions for an individual.

A restrictive red cell transfusion policy has little or no effect on whether: an individual receives an red cell transfusion; Death from any cause occurs; Bleeding occurs; or hospitalization becomes necessary.

We are not sure whether a restrictive red cell transfusion policy will affect quality of life or the risk of developing a serious infection.

No studies were found on: side effects of transfusions; Development of blood clots; Length of stay in intensive care unit; or the need for hospital readmission.

Two ongoing studies (with a planned enrollment of 530 adults) are expected to be completed by January 2018 and will provide additional information for adults with blood cancer. There are no ongoing studies for children.

Quality of the evidence

The overall quality of the evidence was very low to low because the included studies had a significant risk of bias, the estimates were inaccurate, and most of the evidence was only for adults with acute leukemia.