Health related quality of life in sickle cell disease: Just scratching the surface

S ickle cell disease (SCD) is the most common inherited blood disorder in the United States and is associated with considerable morbidity as well as unpredictable and variable symptoms. In children with SCD, this morbidity can negatively affect general health and well-being, cognitive and academic functioning and socio-emotional development which make them an ideal group in which to study health related quality of life (HRQL). HRQL is defined broadly as the assessment of children’s physical, emotional, and social well-being [1,2] and includes key constructs important to research evaluating outcomes in children with chronic diseases. Review of the extant literature reveals several well-validated tools that assess HRQL from the perspective of the child or the parent or both [1,3–5]. However, this review also reveals relatively few studies of HRQL in children with SCD. For example, a cursory review of studies in Medline over the past decade reveals less than 30 studies that mention HRQL in children with SCD. Compared to more than 400 in children with cancer, this suggests that the study of HRQL in patients with SCD is lagging. Moreover, several disease-specific measures of HRQL have been developed and validated for use in children with other chronic diseases including diabetes, cancer, asthma and cardiac conditions, but not SCD [6]. In this issue of Pediatric Blood & Cancer, Brandow et al. examine HRQL in children with SCD specifically in relation to painful events at presentation to the ER and 7 days post-discharge. Not surprisingly, they found that painful events diminished all domains of HRQL and that these domains improve after the pain resolves. This suggests that measures of HRQL are sensitive to these changes in pain severity. This study follows other important studies from Senior author, Julie Panepinto’s research program that have validated HRQL tools in this patient population including the PedsQL [7] and the CHQ [8] and how findings from these measures can differentiate children with SCD on other disease dimensions (e.g., disease severity) [8]. This series of studies also comes at a time when there has been a relative surge in trials designed to improve disease outcomes. Indeed, the last decade has shown several trials designed to evaluate outcomes associated with the use of hydroxyurea in babies [9,10], toddlers [11], children [12], and in patients with stroke (SWiTCH; U01-HL078787; Ware, PI). Importantly, some of these trials have incorporated secondary aims that address QOL outcomes specifically using tools validated by Panepinto et al. For example, in the ongoing SWiTCH trial which evaluates the efficacy of switching from chronic transfusions to HU in the prevention of a second stroke, HRQL is being measured at several key points during the trial using two measures validated in children with SCD to measure HRQL. Brandow et al. have laid the important groundwork in providing a conceptual framework for HRQL in SCD, completed the necessary psychometric studies of two measures of HRQL and demonstrated the feasibility of these measures. In conjunction with the medical advances in hematology that have led to improved life-expectancy for individuals with SCD (from 30 to 40 years previously to 50þ years presently) and possible cure in those who under bone marrow transplants [13–15], it has never been more important to assess HRQL in this group. Ideally this will take the form of continued assessment of HRQL as secondary endpoints in clinical trials, and as primary endpoints in trials designed to improve cognitive and academic functioning and/or those aimed at psychosocial development. Of course, the assessment of HRQL should not end in childhood, but should continue as these children mature into adults who must cope with their disease in the context of other life transitions including college, marriage, and vocational opportunities.