Health Care Utilization Patterns and Emergency Department Reliance During Transition of Care From Pediatric to Adult Providers In Sickle Cell Disease
Authors: Hemker Bradd G. , Brousseau David C , Yan Ke , Hoffmann Raymond G , Panepinto Julie A. 
Published: October 2019

Abstract
Abstract 83

Background:
Improved survival of patients with sickle cell disease has led to increased attention on the transition of care from pediatric to adult providers. Recent studies have shown increased emergency department (ED) utilization as well as an increased risk of mortality during this transition period for patients with sickle cell disease. Suggested reasons for such changes include loss of a medical home, loss of insurance, and loss of access to outpatient clinics as pediatric sickle cell patients transition to adult services. Emergency Department Reliance (EDR), defined as the number of ED visits divided by the number of ED and outpatient visits, views ED visits in relation to all ambulatory visits. Those with more severe disease, who utilize the ED more, should also have more outpatient visits, while those without adequate outpatient clinic access simply use the ED more without a rise in outpatient clinic visits, thus increasing EDR. EDR, therefore, is used to differentiate increased ED use due to need for care from increased ED use as an access issue. We hypothesized that as patients transition from pediatric to adult centered care, loss of a primary medical home would lead to an increase in the EDR.

Methods:
We conducted a retrospective cohort study using the Wisconsin State Medicaid database from 2003–2007. This database includes 757 patients of any age with sickle cell disease who are part of the Wisconsin Medicaid system. Consistent with previous literature, having sickle cell disease was defined by having at least one inpatient hospitalization, or two outpatient visits at least one month apart, with a diagnosis of sickle cell disease. All encounters during the study period were extracted from the database and linked by unique anonymous identifiers. Information extracted included age, all diagnosis codes, and classification as ED visit, outpatient visit, or inpatient hospitalization. The study population was divided into three mutually exclusive age groups: 1) children: ≤ 18 years old for the entire study period, 2) the transition group who turned 19 years old during the study period; and 3) Young adults age ≥ 19–45 years at first encounter. Adults age 3 46 at first encounter were eliminated from the analysis as the goal was to compare the transition group to the age groups immediately above and below. The median Emergency Department Reliance (ED visits/[ED + outpatient visits]) was compared for each age group for sickle cell related diagnoses, all diagnoses, and sickle cell crisis diagnoses using non-parametric, multiple-comparisons adjusted tests.

Results:
The 687 remaining patients had a total of 32,258 ambulatory visits over the five year study period, including 20,418 outpatient visits and 11,840 emergency department visits. There were 345 children, 65 patients in the transition group, and 277 young adults. For sickle cell diagnoses, the transition group had a significantly higher EDR than children (0.50 vs. 0.39, p=0.031) and a higher EDR than young adults, though this increase failed to achieve statistical significance (0.50 vs. 0.41, p=0.360). The difference in EDR between the children and adults for sickle cell diagnoses was not significant. A similar pattern emerged when computing EDR based on all diagnoses, with the EDR for the transition group being significantly higher than for children (0.35 vs. 0.28, p<0.001) as well as increased compared to adults, although this did not reach statistical significance (0.35 vs. 0.31, p=0.073). Lastly, the EDR was highest in all age groups for sickle cell crisis diagnoses (EDR ≥ 0.68 in all three groups).

Conclusions:
Patients with sickle cell disease who are transitioning from pediatric to adult centered care have an increased reliance on the emergency department as a location of care for sickle cell diagnoses. As adults, emergency department reliance returns to similar levels as childhood, suggesting a stabilization of a medical home following the transition period. The EDR is highest for all groups at times of acute pain crisis related to sickle cell disease, consistent with the need for emergent care in those situations. These findings support the hypothesis that increased ED utilization during the transition period from pediatric to adult providers is potentially due to limitations in access to care.

Disclosures:
No relevant conflicts of interest to declare.