Discussion
Despite the evidence for increased hardships and hospitalizations for
transition-aged patients with SCD, we lack recent, nationwide studies
pertaining to the trends in this population’s mortality. Previous
studies are now dated or had a narrow emphasis, focusing on specific
demographics such as geographic regions. We thus embarked on a
comprehensive approach to examine recent, national data regarding
transition-aged hospitalizations in the SCD population. The Healthcare
Cost and Utilization Project (HCUP)’s 2019 Statistical Brief #251
reported that 18-34 year-old patients comprised the majority (50.7%) of
SCD stays between 2000-2016, a vast difference when compared to non-SCD
admissions in which 18-34 year-olds only made up 16.3%. However, in
focusing on ages 16-24 specifically, our results did not show a
difference in the portion of transition-age hospitalizations between SCD
and non-SCD cohorts (Table 1). The HCUP brief also highlighted various
socio-economic differences between SCD and non-SCD admissions.
Correspondingly, we noted transition-aged patients with SCD were more
likely to have public insurance, be in the lower zip income quartile and
have a discharge status of DAMA (Table 1).
Furthermore, we were interested in the mortality risk among different
SCD transition-age cohorts. We were astonished to see that in comparison
to teens aged 16-18, the risk in mortality was 2-fold higher for those
aged 19-21, and nearly 3-fold higher for ages 22-24 (Table 2). These
findings corresponded with 1999-2009 data obtained by Hamideh et al
which demonstrated a sharp increase in the morality rate in patients
with SCD between 15-19-years-old to 20-24-years-old.
An additional finding pertained to mortality differences based on
documented sex. Female patients constituted a slight majority of
patients hospitalized with sickle cell disease (Table 1), however, they
were less likely to suffer in-hospital mortality when compared to their
male counterparts (Table 2; p < 0.0001). These results align
with a previous study which determined that pediatric male patients with
SCD have a worse, more aggressive clinical course than females and an
increased morbidity.
Limitations of our study are related to the nature of database
utilization; specifically, the absence of granular data and the
inability to track a patient over time. Due to this, cause of death and
other information regarding clinical course is unobtainable.
Furthermore, the structure of the NIS data was confined to inpatient
admissions only and did not contain ED visits, outpatient visits or
urgent care visits. Despite some limitations, our study was highly
powered in detecting differences in hospitalizations and mortality
associated with SCD due to the large sample size. The NIS data was
composed of weighted national samples, representative of the entire
population rendering the findings in this study to be generalizable.
Several groups have underscored the vulnerability of patients with
chronic diseases during the transition period; the consensus is that
this period is plagued by social, psychological, and physiological
hardships. For patients with SCD in particular, these challenges exist
in a sort of cyclic nature, where increased pain episodes and fatigue
lead to anxiety and depression, decreasing a patient’s health-related
quality of life and in turn further exacerbating the fatigue and pain
episodes. These pain episodes, or vaso-occlusive crises, are the leading
cause of SCD admissions, and serve as a primary risk factor for
potential life-threatening events.
Our study has demonstrated the necessity for multifaceted improvements
in the process of transitioning our pediatric patients with SCD to adult
care. A 2009 survey showed that the vast majority of transitioning
patients with SCD did not feel ready to transition, with only 34% of
participants knowing which hospital they planned to transition to. Thus
highlighting the importance of addressing barriers to transition
readiness. A proposed solution to this problem has been the
implementation of SCD transition programs and centers, however the
efficacy and sustainability of these programs is still being monitored.
Additionally, in a 2014 study regarding the risk factors for a
successful transition, Andemariam et al. found that a greater distance
between transition centers and patients with SCD was associated with
unsuccessful transitioning. This underscores the importance of
accounting for social determinants of health when addressing the
transition process.
A further barrier to successful transition is a lack of knowledgeable
providers. In a 2011 study that surveyed pediatric providers at several
SCD centers, Sobota et al. found that only 60% of centers sent their
patients to hematologists specializing in adult SCD and noted that some
centers sent their patients to internist instead. Providers also noted
that difficulty in finding adult SCD physicians was a large barrier for
transition. This corresponds with evidence that transition-aged patients
are less likely to receive disease-modifying therapies following
childhood.
The final point is that age should be taken into consideration for
transition. Andemariam et al. also found that an older age at the time
of initiating the transition process correlated with unsuccessful
transition (2014). Coupled with our findings of higher mortality with
increasing transition age, it is imperative that transition readiness
education begin in early adolescence.