Introduction

Sickle cell disease (SCD) is the most common hemoglobinopathy affecting millions of people worldwide.1 SCD is caused by a single point mutation in the β-globin gene. This gene mutation leads to formation of abnormal hemoglobin known as hemoglobin S (HbS). Upon deoxygenation, HbS polymerizes into long chains, thereby changing the shape of red blood cells into a stiff, sickle-shaped form causing acute and chronic complications including vaso-occlusion, chronic hemolysis, and multi-organ damage.2 Vaso-occlusion along with impaired oxygen supply and reperfusion of injured tissues causes acute pain.3 These recurrent and unpredictable so-called vaso-occlusive crises (VOCs), are frequently located in the chest, back or abdomen, but may affect every part of the body. In patients with SCD, the frequency of VOCs ranges between 0 to 18 VOCs per year.4 Although VOCs are primarily managed at home with oral or suppository analgesic agents, they are the most common cause for hospitalization and emergency department visits in patients with SCD.5-7 In some cases, VOCs are complicated by the development of an acute chest syndrome, that may be life-threatening and require admission to the pediatric intensive care unit.
Nowadays, disease-modifying therapies including hydroxyurea8, voxelator9 and crizanlizumab,10,11 and curative therapies such as stem cell transplantation are becoming more available for the management of SCD. Unfortunately not all patients have access to these treatments and not all VOCs can be prevented.12-14 VOCs have a negative impact on all aspects of patient’s lives, not only physically, but also emotionally and socially.15 As screening programs and preventative measures have led to higher survival among children with SCD, SCD has now transformed into a more chronic disease,16,17 and more attention is required for the substantial personal and societal burden.

Health-related quality of life

Health-related quality of life (HRQoL) refers to the perceived wellbeing in physical, mental and social domains of health18, and is a patient-reported outcome (PRO) as it is assessed by patients themselves (self-reported).19,20 In children, HRQoL can be assessed by the caregiver (proxy-reported) as well. Validated questionnaires to systematically monitor HRQoL are called patient-reported outcome measures (PROMs). In the Emma Children’s Hospital, the KLIK PROM portal (www.hetklikt.nu) is used to routinely measure HRQoL in daily clinical practice with PROMs.21-23
Previous research has shown that HRQoL is significantly affected in children with SCD, in both self- and proxy-reported HRQoL studies.17,24-28 Children with SCD had a substantially lower HRQoL compared to both the general pediatric population, and other children with chronic disorders.26,27,29-31 The painful VOC strongly affects the HRQoL more than any other SCD-related complication such as avascular necrosis or stroke.32This is likely due to lack of control, effective therapeutic interventions29 and the difficulty of pain management.33 In particular health care utilization seems to be a strong predictor for worse HRQoL in children with SCD.34
While research has been conducted on the impact of VOC on HRQoL of pediatric patients with SCD, no studies have evaluated the cumulative longitudinal effect of hospitalization on HRQoL. Longitudinal analyses allow us to evaluate the impact of hospitalization on HRQoL over time. Therefore, the aim of this study is to identify the longitudinal impact of hospitalization for VOC on HRQoL in children with SCD with real-world data, up to one year after hospitalization. Identifying the impact of hospitalization allows healthcare providers to provide adequate psychosocial support as part of interdisciplinary pain management to improve HRQoL.