Background: Sickle cell disease (SCD) is characterized by vaso-occlusive crises (VOCs), that impair the health-related quality of life (HRQoL). The aim of this study is to evaluate the impact of hospitalization for VOCs on HRQoL in children with SCD over time. Methods: In this longitudinal cohort study, children aged 8-18 years diagnosed with SCD at the Amsterdam UMC were included between 2012 and 2021. HRQoL was annually measured as part of standard care using the Pediatric Quality of Life Inventory. The impact of hospitalization for VOC on HRQoL was evaluated using linear mixed models 3, 6, 9 and 12 months after hospitalization. The effect of frequency of hospitalization for VOC on HRQoL was evaluated over the last 12 months. Results: In total , 94 children with SCD were included with a median age of 11.8 years (IQR 9-14). Thirty-seven patients (39%) had been hospitalized for a VOC. Hospitalization for VOC led to a decrease of 3.2-4.8 points in total HRQoL compared to patients without hospitalization, most pronounced 3 months after hospitalization. Recurrent admission for VOC in the last 12 months was associated with a decrease of 2.3 points in total HRQoL (p=0.04). The most affected subscale was physical functioning. Conclusion: The adverse effects of hospitalization for VOC in children with SCD persist up to 12 months after hospitalization. After hospitalization for VOC, extra attention and support for its negative impact on HRQoL are recommended. This study also underlines the importance of systematically measuring HRQoL allowing clinicians to intervene accordingly.

Background Recombinant factor IX Fc fusion protein (rFIX-Fc) is an extended half-life (EHL) factor concentrate administered to haemophilia B patients. So far, a population pharmacokinetic (PK) model has only been published for patients ≥12 years of age. Aim Assess the predictive performance of the published rFIX-Fc population PK model for patients of all ages and develop a model that describes rFIX-Fc PK using real world data. Methods We collected prospective and retrospective data from patients with haemophilia B (FIX activity level ≤5 IU/dL) treated with rFIX-Fc and included in the OPTI-CLOT TARGET study (NTR7523) or United Kingdom (UK)-EHL Outcome Registry (NCT02938156). Predictive performance was assessed by comparing predicted with observed FIX activity levels. A novel population PK model was constructed using nonlinear mixed-effects modelling. Results Real world data was obtained from 37 patients (median age: 16 years, range 2-71) of whom 14 were <12 years of age. Observed FIX activity levels were significantly higher than levels predicted using the published model, with a median prediction error (PE) of -48.8%. The novel model showed a lower median PE (3.4%) and better described rFIX-Fc PK, especially for children <12 years of age. In the novel model, an increase in age was correlated with a decrease in clearance (p<0.01). Conclusion The published population PK model significantly underpredicted FIX activity levels. The novel model better describes rFIX-Fc PK, especially for children <12 years of age. This study underlines the necessity to strive for representative population PK models, thereby avoiding extrapolation outside the studied population.

Background: Pain is the clinical hallmark of sickle cell disease (SCD) leading to hospitalization, psychological sequelae and a decreased health-related quality of life. The aim of this systematic literature review is to evaluate the efficacy of non-pharmacological interventions in reducing sickle cell-related pain in children with SCD. Methods: A comprehensive literature search up until October 2022 was performed to identify studies that investigated the efficacy of non-pharmacological interventions on (1) pain frequency and/or intensity, and (2) analgesic and health service use in children with SCD. Randomized controlled (RCTs) trials and quasi-experimental designed (QED) studies that investigated non-pharmacological interventions for pediatric patients with SCD until the age of 21 years were considered for inclusion. Results: Ten articles (5 RCTs and 5 QED studies) with 422 participants were included. They investigated cognitive behavioral therapy (CBT) (n =5), biofeedback (n=2), massage (n=1), virtual reality (n=1) and yoga (n=1). CBT, biofeedback, massage, virtual reality and yoga significantly reduced frequency and/or intensity of SCD-related pain. Biofeedback also significantly reduced analgesic use. Conclusion: Non-pharmacological interventions may be effective in reducing pain in pediatric SCD patients. However, due to the heterogeneity of the included studies a quantitative analysis could not be performed. Awaiting further supporting evidence, healthcare providers should consider implementing these interventions as valuable part of a comprehensive pain management strategy plan to improve the outcome of sickle cell-related pain.