The Registry is developed in Phase I and continues through Phase II with the goal of enrolling 2400 patients (300 per center) between the ages of 15 and 45 years to conduct comparative studies related to guidelines and recommendations and to address evidence-based management of SCD. The Registry leverages the availability of CDEs in sickle cell disease developed under the PhenX Project and PROMIS to collect standard clinical measures, laboratory values, lifestyle factors, medical history, treatment, healthcare utilization, and patient reported outcomes associated with pain, co-morbidities, quality of life, physical functioning, mental health and barriers to care. Longitudinal data is collected on study subjects throughout study period. The Registry is a resource for identifying gaps in research, conducting data queries and analyses that lead to development and implementation of research studies, and dissemination of research findings from the Registry data.