Population
Adult patients with sickle cell disease (7 studies).
Intervention
Hydroxyurea.
Comparison
Several comparators, including: L-glutamine, voxelotor and crizanlizumab.
Outcome
The majority of the studies focused on mean and median annual rates of vaso-occlusive crises (VOCs) as primary outcomes while median time to first sickle cell crises and median rates of hospitalizations were evaluated as secondary outcomes. The literature suggested that many patients with VOCs were still benefitting from hydroxyurea therapy since long term efficacy data and cost was still a concern for newer agents such as: L-glutamine, voxelotor and crizanlizumab.