Pilot Results from an Integrated Pediatric Pulmonary Clinic on Outcomes in Children with Sickle Cell Disease

Introduction

In children with sickle cell disease (SCD), asthma is a common comorbidity and is associated with increased disease severity when compared to children with SCD without asthma. Other pulmonary conditions, such as obstructive sleep apnea (OSA), are also more common in SCD and adversely affect clinical outcomes. Despite the well-established burden of pulmonary disease in children with SCD, optimal treatment paradigms are not well defined.

Methods

An integrated pediatric SCD and pulmonary clinic guided by the chronic care model was implemented at the University of Florida in July 2017 with the goal of coordinating subspecialty care and improving the treatment of concomitant pulmonary conditions. Prior to the formation of this clinic (pre-intervention phase), patients were managed separately by pulmonologists and hematologists in a tertiary academic medical center. During the intervention phase, patients received care in an interdisciplinary clinic composed of a pediatric pulmonologist, a pediatric hematologist with expertise in SCD, a respiratory therapist with access to an onsite pulmonary function testing (PFT) laboratory, asthma educator, and a SCD nurse educator/clinic coordinator. The objective of this abstract is to evaluate preliminary clinical outcomes of the integrated SCD-pulmonary clinic during the intervention phase (July 2017-June 2018) compared to 24 months prior to implementation (July 2015-June 2017). We hypothesized an integrated clinic model would improve access to specialized pulmonary care for children with SCD and reduce hospitalizations for vaso-occlusive episodes (VOEs). The primary endpoints are adherence to pulmonary clinic appointments and unplanned acute healthcare utilization for SCD-related complications and/or asthma exacerbations. Secondary endpoints are the number of unplanned packed red blood cell (PRBC) transfusions, percentage of patients able to complete PFTs, and new diagnoses or prescribed treatments during the intervention phase.

Results

During the intervention phase, 24 unique patients accounted for 40 clinic visits. Reasons for referral to the integrated SCD-pulmonary clinic included asthma (16), a history of severe and/or recurrent acute chest syndrome (12), OSA (3), hypoxia (1), shortness of breath (1), and concern for pulmonary hypertension (1). The mean age of participants was 10 years (range 2-18 years); 79% were male, 22 had hemoglobin (Hb) SS disease, 16 (67%) were being treated with hydroxyurea, and 2 were on chronic transfusion therapy. Mean baseline Hb and reticulocyte count were 9.1 gm/dL (SD 1.2) and 8.5% (SD 4.5), respectively. PFTs were successfully completed in 21 (88%) patients and reported as pre-treatment percent predicted values after adjusting for age, gender, height, and race. Mean forced expiratory volume in 1 second (FEV1) was 90% (SD 12.5), forced vital capacity (FVC) 94% (SD 12), and diffusing capacity of the lungs for carbon monoxide (DLCO) corrected for Hb was 103% (SD 26, measured in 12 patients). Mean duration of follow-up was 8 months (range 1-12 months). During the pre-intervention phase, this cohort accounted for 76 hospitalizations, 42 emergency department (ED) visits, 31 transfusions, and 26 missed pulmonary appointments. During the intervention phase, there were 9 hospitalizations, 7 ED visits, 3 transfusions, and 5 missed appointments. This represents an 86% reduction in unplanned acute healthcare utilization (mean difference (MD) 2.8, 95% CI 1.8-3.7; p<0.0001), a 90% reduction in PRBC transfusions (MD 1.9, 95% CI 0.96-2.78; p<0.001), and an 81% increase in adherence to pulmonary appointments (MD 1.3, 95% CI 0.71-1.92; p<0.001). Twenty-two patients had a confirmed asthma diagnosis, and 8 were diagnosed with OSA. Interventions included personalized asthma action plans (22 patients), inhaled corticosteroids (16), supplemental oxygen during sleep (5), tonsillectomy and adenoidectomy (2), and the initiation of hydroxyurea (1).

Conclusions

These results demonstrate that interdisciplinary clinics can improve access to subspecialty pulmonary care for children with SCD and support the continued development and implementation of integrated care models. With limited follow-up, the results also suggest integrated SCD and pulmonary care can reduce hospitalizations and ED visits for VOEs, though additional follow-up is required to determine the true treatment effect.