The effect of prolonged administration of hydroxyurea on morbidity and mortality in adult patients with sickle cell syndromes: results of a 17-year, single-center trial (LaSHS). Blood. 2010;115:2354-2363. [PMID: 19903897 DOI: 10.1182/blood-2009-05-221333]

The risks and benefits of long-term use of hydroxyurea in sickle cell anemia: A 17.5 year follow-up

A randomized, controlled clinical trial established the efficacy and safety of short-term use of hydroxyurea in adult sickle cell anemia. To examine the risks and benefits of long-term hydroxyurea usage, patients in this trial were followed for 17.5 years during which they could start or stop hydroxyurea. The purpose of this follow-up was to search for adverse outcomes and estimate mortality. For each outcome and for mortality, exact 95% confidence intervals were calculated, or tests were conducted at alpha = 0.05 level (P-value <0.05 for statistical significance). Although the death rate in the overall study cohort was high (43.1%; 4.4 per 100 person-years), mortality was reduced in individuals with long-term exposure to hydroxyurea. Survival curves demonstrated a significant reduction in deaths with long-term exposure. Twenty-four percent of deaths were due to pulmonary complications; 87.1% occurred in patients who never took hydroxyurea or took it for <5 years. Stroke, organ dysfunction, infection, and malignancy were similar in all groups. Our results, while no longer the product of a randomized study because of the ethical concerns of withholding an efficacious treatment, suggest that long-term use of hydroxyurea is safe and might decrease mortality.

Hydroxyurea enhances sickle survival

In this issue of Blood, Voskaridou et al provide more compelling evidence that hydroxyurea improves survival in adults with severe sickle cell disease.1 This comes at the centennial of the recognition of sickle cell disease in Western medicine. Considerable progress has been made in understanding the pathophysiology of this complex disease caused by a single nucleotide change in the β-globin gene that causes replacement of glutamic acid by valine.