Transition to adult care in sickle cell disease: A longitudinal study of clinical characteristics and disease severity.

BACKGROUND: Sickle cell disease (SCD) is a chronic blood disorder in which mortality has increased for adolescents and young adults (AYA). PROCEDURE: A longitudinal analysis of medical records was conducted to describe the clinical course among AYAs (ages 12-27 years) during transition to adult care. Measures included sociodemographic, complications, SCD severity (modified pediatric SCD severity index), comorbidities, and transfer. Group-based trajectory modeling (GBTM) to identify subgroups with distinct severity trajectories and chi-square and unpaired Student t test to explore subgroup differences were used. RESULTS: Overall, 339 AYAs (97% black, 56% male, 69% hemoglobin SS) had 10 848 clinic, 3840 hospital, and 3152 emergency department visits. Complications included vaso-occlusive crises (80%) and acute chest syndrome (41%). Comorbidities included depression (19%) and anxiety (14%). Most AYAs transferred to adult care (n = 220) at 19 years. Fourteen AYAs died, 10 within seven years from transfer. GBTM identified both stable and increasing severity trajectory groups: stable-low (n = 31, 23%), stable-medium (n = 61, 46%), stable-high (n = 6, 4.5%), low-increasing (n = 13, 10%), and medium-increasing (n = 22, 17%). AYAs with increasing severity (25%) were older, lived closer to the clinic, and had higher risk for SCD complications and comorbidities. They had fewer pediatric clinic visits; however, they were more likely to transfer and remain longer in adult SCD care. CONCLUSIONS: Whereas most AYAs had stable severity, nearly a quarter had increasing severity, over time. AYAs with increasing severity had more complications, were more likely to transfer to adult care, and demonstrated higher and longer adult SCD care utilization compared with AYAs with stable severity.