Distance from an Urban Sickle Cell Center and its Effects on Routine Healthcare Management and Rates of Hospitalization

Abstract

The St. Jude Children’s Research Hospital (St. Jude) comprehensive sickle cell center serves a 150 mile catchment radius around Memphis, TN, USA. Full travel expenses are provided for routine and acute care visits for sickle cell disease patients living ≥35 miles from St. Jude. We compared hospitalization rates to national estimates and assessed if driving distance was a barrier to sickle cell healthcare despite the travel reimbursement policy. We evaluated the associations between hospitalizations and routine clinic visits and distance from St. Jude using negative binomial models and we conducted bias analyses by Monte Carlo simulation. We followed 545 patients (2550 patient-years) aged ≤18 years with sickle cell disease (Hb SS only) from 2007 to 2012. The hospitalization rate per patient-year was 0.65 [95% CI (confidence interval): 0.62, 0.68), significantly lower than the national rate of 1.16 (95% CI: 1.14, 1.18). Children living <35 miles from St. Jude had 1.75 (95% CI: 1.41, 2.17) times the rate of hospitalization and 1.22 (95% CI: 1.07, 1.39) times the rate of clinic visits compared to those ≥35 miles. Bias analysis suggested that under-reporting could explain the observed difference in hospitalization rates if 30.0% of patients who lived ≥35 miles from the hospital under-reported six hospitalizations over 6 years. The hospitalization rate at St. Jude in children with sickle cell disease was lower than expected from national rates. Greater distance from the sickle cell center (>35 miles) was associated with decreased hospitalization rates, despite the travel allowances that are provided for those who live ≥35 miles from the hospital.