Acute vaso-occlusive painful events impact children with sickle cell disease and their caregivers. The morbidity of a painful event that brings a child to medical attention does not end once the child is discharged to home. The data from our study show that children experience persistent pain at home after discharge from medical treatment for vaso-occlusive painful events and this pain likely contributes to further functional limitations, including school absenteeism. Our findings further expand the previously documented relationship between pain experienced at home and school absenteeism (Shapiro et al, 1995
; Gil et al, 2000
; Dampier et al, 2002a; Dampier et al, 2002b). In addition, our findings show that children have almost two days of pain at home prior to seeking medical care and even seeking medical care in the emergency department or inpatient unit does not mean the end of a painful episode. These data underscore the fact that sickle cell pain that occurs at home is a problem that disrupts school attendance and likely other activities of daily living.
The impact of vaso-occlusive painful events at the school level is not trivial. Previous studies have shown that children with sickle cell disease are at risk of poor academic attainment (Wang et al, 2001
; Steen et al, 2005
; Herron et al, 2003
; Schatz, 2004
; King et al, 2008
; King et al, 2006
). Poor academic attainment in children with sickle cell disease is a multifactorial problem; nevertheless, the number of missed school days while children are hospitalized for painful events has been shown to be predictive of poor academic attainment (Herron et al, 2003
; Schatz, 2004
; Taras & Potts-Datema, 2005
). In our study, on average, children were hospitalized for three days resulting in school absenteeism with an additional two days of school absenteeism post-discharge. Therefore, a single painful event can result in five missed school days. For children with frequent painful events, who also had the worst outcomes in our study, painful events alone have an impact on their ability to attend school. In addition, these data do not account for other issues that may impact the school attendance of children with sickle cell disease such as admissions for fever or other sickle cell disease related complications, and admissions for other non-sickle cell disease related acute or chronic medical conditions, such as asthma.
We also found that vaso-occlusive painful events affect the caregiver’s ability to work or attend school which can in turn impact the socioeconomic status of the family. This is extremely important for children with sickle cell disease because they are more likely to live in poverty (Barbarin et al, 1999
; Hill, 1994
), and many caregivers of these children are single parents, thus they need to work outside the home because they are the sole provider for the entire family (Hill, 1994
). In addition, people of lower socioeconomic status are more likely to have jobs that do not give them sick leave or flexible work hours that allow them to care for a sick child (Smith et al, 2002
). Caregivers of children with chronic diseases have identified high child health care use leading to missed work days as a barrier to employment, thus parents of children with chronic medical conditions are more likely to be unemployed (Smith et al, 2002
; Kuhlthau & Perrrin, 2001). For children with sickle cell disease, the unpredictability of painful events can lead to multiple absences from work for caregivers which could ultimately lead to unemployment. Thus, when a chronic disease, such as sickle cell disease, is introduced to an already impoverished family, the impact of missed work and potential unemployment on socioeconomic status is crucial to the welfare of the entire family. Our study illustrates that a single painful event results in missed days of work/school for caregivers and for those children with frequent painful events, this impact is magnified and could further negatively impact the socioeconomic status of the entire family.
When new interventions are developed, it is important to identify high risk patient groups that could benefit from these interventions. Our data show that children with a history of three or more vaso-occlusive painful events requiring inpatient admission in the year prior to study enrollment had significantly increased odds of experiencing poor outcomes post-discharge. Therefore, our data provide further evidence that these children make up a high risk cohort and should be targeted for interventional studies to improve their outcomes in the post-discharge period and novel new therapies to treat acute events such as intravenous magnesium (Brousseau et al, 2004
). In addition, these children should be evaluated for known preventive therapies for pain such as hydroxyurea (NIH Pub No.02-2117, 2002
; Charache et al, 1995
; Steinberg et al, 2003
; Scott et al, 1996
; Ferster et al, 1996
), bone marrow transplantation (Panepinto et al, 2007
), chronic blood transfusions, or other future clinical trials developed to decrease the frequency of painful events.
Interventional studies for vaso-occlusive painful events have used length of hospital stay as an outcome endpoint (Brousseau et al, 2004
; Weiner et al, 2003
). However, our study shows the morbidity of painful events does not end the day a child is discharged to home. Using length of hospital stay as a primary outcome measure of a vaso-occlusive painful event does not account for what happens when the child is home. Therefore, when measuring the effectiveness of new interventions for vaso-occlusive painful events, it is imperative to assess the morbidity children experience at home in the post-discharge period in addition to length of hospital stay. In addition, this study provides a model for hospital follow-up that could be utilized in a multi-center observational study aimed at longitudinally assessing the outcomes of painful events.
Unexpectedly, older age portended slightly decreased odds of experiencing poor outcomes post-discharge. Since the number of vaso-occlusive painful events and length of hospital stay has been shown to increase with age (Panepinto et al, 2005
) we hypothesized older children would have worse outcomes, the opposite of what we found in our study. Upon further analysis of pain and functional limitations in older (≥ 9 years) versus younger (< 9 years) children, we found similar days of pain post-discharge in both groups, however, older children had fewer days of functional limitations (including school absenteeism) post-discharge than younger children. This suggests that perhaps older children have adapted or adjusted to the pain from their disease, thus reintegrating themselves into their lives sooner than younger children. These data could also suggest that younger children may miss more school as a function of greater influence of parental decision making on their return to school. Finally, these data may suggest that older children have more chronic pain that follows the epidemiological pattern of pain in adults that has recently been described (Smith et al, 2008
). This observation warrants additional longitudinal work to further elucidate the affect of age on the outcomes of individuals.
This study is limited by data that are self-reported. Recall bias of self-reported days of pain prior to presentation is also a potential limitation. In addition, the outcomes assessed post-discharge are also subject to recall bias. However, this was likely minimized by contacting families at two points in time post-discharge. Like many studies, this sample reflects the experience of a single center and outcomes may vary from center to center. Therefore, multi-institutional studies would be important to evaluate the pattern of outcomes at other centers. Our study did not find a difference in overall outcome between children discharged from the emergency department versus those discharged from the inpatient unit and did not find a difference in outcomes based on genotype of sickle cell disease. However, this study was not powered to find such differences and a larger study would be required to test this hypothesis. In addition, our sample size only allowed for dichotomization of our outcome into two groups (good and poor). A larger study would allow dichotomization into additional groups, such as a moderate outcome category. There is currently no standard classification for severity of sickle cell disease and there is inherent variability of the severity of an individual painful event. This lack of severity classification and lack of a validated risk adjuster for length of pain in sickle cell disease make risk adjusted analysis in the study difficult, therefore, this remains a limitation to the study. Finally, this study assessed a single vaso-occlusive painful event per child and was not designed to be a longitudinal study to follow children over time.
In conclusion, we provide new evidence that vaso-occlusive painful events impact the function of children with sickle cell disease and their caregivers even after discharge from medical care. Children experience poor outcomes at home that manifest as persistent pain and functional limitations for the child, including school/daycare absenteeism, and work/school absenteeism for the caregiver. A history of three or more vaso-occlusive painful events is a risk factor for persistent pain, functional limitations for the child and missed days of work/school for the caregiver. Therefore, this study provides further evidence that these children make up a high risk cohort and should be targeted for medical, social, and school interventions. In addition, when examining the impact of interventional studies on vaso-occlusive painful events, post- discharge assessment is necessary in determining the length of painful events. Finally, interventions to improve outcomes in the post-discharge period are imperative to improve the quality of life of children affected by this chronic debilitating disease.