Sickle cell disease is a blood disorder, and means the part of the red blood cell that carries oxygen from the lungs to the body tissues (haemoglobin) is abnormal. It is a genetic disorder and occurs when people inherit abnormal genes from both parents. It is more common in people originating from tropical Africa, and the Caribbean, Mediterranean, Indian, and Middle Eastern regions. Some types of sickle cell disease cause more severe symptoms than others, but in general people with the disease may be tired and weak (due to anaemia), and have severe and recurrent pain in the bones (referred to as crises), have more infections, more problems with breathing, and more chance of having a stroke. Sickle cell disease contributes to the death of children in the first five years of life, and infants aged six to 12 months are particularly at risk. Malaria infection is known to trigger a sickle cell crisis. So preventing malaria in people with sickle cell disease may also help to reduce crises and all the problems that go along with it. Health professionals often recommend life-long drugs to prevent malaria infections (chemoprophylaxis) for people with sickle cell disease living in these high risk areas for malaria. However, it is important to assess how effective this may be and what the adverse effects there might be from taking these drugs over a long period of time. This review of trials identified two small trials involving 223 people with homozygous sickle cell disease (commonly called sickle cell anaemia). These showed benefit in terms of reducing the number of sickle cell crises, blood transfusions, hospital admissions, and increasing the mean haemoglobin levels, but they did not collect data on potential adverse effects. More research is needed, therefore, to be sure of the benefits and to assess possible problems of drug resistance, and other potential long-term adverse effects that may be associated with continuous treatment.
It is beneficial to give routine malaria chemoprophylaxis in sickle cell disease in areas where malaria is endemic.
Malaria is the most common precipitating cause of crises in sickle cell disease in malaria-endemic countries. Health professionals often recommend life-long malaria chemoprophylaxis for people with sickle cell disease living in these areas. It is therefore important we have good evidence of benefit.
To assess the effects of routine malaria chemoprophylaxis in people with sickle cell disease.
We searched the Cochrane Infectious Diseases Group Specialized Register (January 2006), Cochrane Cystic Fibrosis and Genetic Disorders Group Specialized Register (July 2006), CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE (1966 to January 2006), EMBASE (1974 to January 2006), LILACS (1982 to January 2006), and reference lists. We also contacted organizations and pharmaceutical companies.
Randomized and quasi-randomized controlled trials comparing chemoprophylaxis with any antimalarial drug given for a minimum of three months compared with a placebo or no intervention.
Two authors independently applied the inclusion criteria, assessed the risk of bias in the trials, and extracted data. Dichotomous data were analysed using risk ratios (RR) and presented with 95% confidence intervals (CI).
Two trials with a total of 223 children with homozygous sickle cell disease met the inclusion criteria. A randomized controlled trial in Nigeria compared two different antimalarial drugs with a placebo, and reported that chemoprophylaxis reduced sickle cell crises (RR 0.17, 95% CI 0.04 to 0.83; 97 children), hospital admissions (RR 0.27, 95% CI 0.12 to 0.63; 97 participants), and blood transfusions (RR 0.16, 95% CI 0.05 to 0.56; 97 participants). A quasi-randomized controlled trial of 126 children in Uganda compared an antimalarial drug plus antibiotics with no antimalarial plus placebo. Chemoprophylaxis reduced the number of episodes of malaria and dactylitis, and increased mean haemoglobin values in this trial.