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

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. To assess the relative risks and benefits of drugs which aim to prevent sickle cell-related crises by reducing red blood cell dehydration. 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. 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. Both authors independently selected studies for inclusion, assessed study quality and extracted data from the included studies. 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. 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.