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.