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Comparison of Clinical Outcomes Between Adult and Pediatric Patients (pts) with Sickle Cell Disease (SCD): 3-Year (y) Follow-up in a Prospective, Longitudinal, Noninterventional Registry Trial

Matthew M. Heeney, Brad Baltz, Patricia Adams-Graves, Elizabeth Yang, Carole Paley, Jason Esposito, Katie McNamara, Elliott Vichinsky and Alex George

Abstract

Introduction: Although advances in care have allowed individuals with SCD to live further into adulthood, treatment of adult SCD pts is challenging due to increased rates of comorbidities and complications. Here we present clinical outcomes and treatment patterns from a prospective registry of pediatric and adult pts with SCD at 3 y to better characterize disease and treatment patterns in adult pts.

Methods: Pts ≥2 y old with HbSS, HbSC or HbS/β-thalassemia were enrolled from 57 US centers and assessed every 6 mo until 3 y. Differences between pediatric (<18 y) and adult pts at 3 y are reported.

Results: Among 498 pts (317 pediatric; 181 adults) completing baseline visit, 74.1% had HbSS, 15.3% HbSC and 10.4% HbS/β-thalassemia; 61 pts discontinued the study. At baseline, pediatric pts had more asthma/airway reactive disease, dactylitis, and splenic sequestration (Table 1). Adults had significantly poorer performance status (P<0.0001) and more avascular necrosis (AVN), gallbladder disease (GBD), leg ulcers, and pulmonary hypertension (PAH). The most common SCD crisis was pain, both in the 5 y prior to study (86.2% of adults, 72.2% of children) and during study (64.1% of adults, 69.4% of children; Table 2). During study, more pediatric pts had respiratory conditions, including acute chest syndrome (ACS). More than half of all pts were hospitalized; key reasons were pain, fever, and ACS. Significantly more pediatric pts were hospitalized due to fever (P<0.0001) and significantly more adult pts were hospitalized for transfusion/chelation (P=0.0336). Absenteeism from school/work was frequent prior to and during study.

Conclusions: Patterns of disease and complications differed between children and adults. Adults had more hospitalizations due to transfusions/chelation and more classic chronic conditions (eg, AVN, GBD and PAH). Absenteeism from school/work was common in both groups. Limitations included the observational study design, variation in time from diagnosis, and lack of mandatory data collection.

<18 y
(n=317)
≥18 y
(n=181)
Age, y, mean±SD8.9±4.4335.2±12.52*
Males, %56.847.0†
SCD genotype, n (%)
HbSS242 (76.3)127 (70.2)
HbSC43 (13.6)33 (18.2)
HbS/β-thalassemia32 (10.1)20 (11.0)
Karnofsky performance status, n (%)
100%105 (33.1)26 (14.4)*
90%64 (20.2)54 (29.8)*
≤80%22 (6.9)63 (34.8)*
Medical history, n (%)
Aplastic episode31 (9.8)15 (8.3)
Asthma/reactive airway disease97 (30.6)29 (16.0)
AVN10 (3.2)61 (33.7)
CNS
Abnormal TCD28 (8.8)7 (3.9)
Seizure15 (4.7)13 (7.2)
Silent infarct23 (7.3)11 (6.1)
Stroke (lifetime)33 (10.4)27 (14.9)
Dactylitis75 (23.7)12 (6.6)
GBD48 (15.1)80 (44.2)
Leg ulcer018 (9.9)
PAH3 (0.9)19 (10.5)
Splenic sequestration75 (23.7)15 (8.3)
TABLE 1.

Baseline Characteristics of Pediatric vs Adult Pts with SCD at 3 Y

*P<0.0001

†P<0.05

CNS, central nervous system; TCD, transcranial Doppler

<18 y
(n=317)
≥18 y
(n=181)
<18 y
(n=317)
≥18 y
(n=181)
Clinical Complications
Pts with SCD crises in 5 y prior to study, n (%)
Pain229 (72.2)156 (86.2)
Infections (≥1)135 (42.6)62 (34.3)
ACS/pneumonia135 (42.6)40 (22.1)
Stroke (lifetime)33 (10.4)27 (14.9)
Priapism14 (4.4)14 (7.7)
Pts with SCD crises in 3 y during study, n (%)
Pain220 (69.4)116 (64.1)
Infections (≥1)113 (35.6)53 (29.3)
ACS/pneumonia62 (19.6)18 (9.9)
Stroke9 (2.8)2 (1.1)
Priapism8 (2.5)3 (1.7)
Pts hospitalized in 3 y during study, n (%)212 (66.9)111 (61.3)
Number of hospitalizations in 3 y during study, n
Causesµ
Pain13591
Fever‡6313 ‡
ACS/pneumonia7028
Transfusion/chelation1417 *
Infections87
Treatments
Pts transfused, n (%)
During 12 mo prior to study138 (43.5)96 (53.0)*
During 3 y on study172 (54.3)93 (51.4)
Chelation therapy, n (%)
Pts ever chelated prior to study63 (19.9)59 (32.6) †
During 3 y on study40 (12.6)19 (10.5)
Pts used hydroxyurea, n (%)
Prior to study146 (46.1)88 (48.6)
During 3 y on study156 (49.2)78 (43.1)
Absenteeism from school/work
Missed school, n (%)
Prior to study (>20 d in last 12 mo)28 (14.7)5 (25.0)
During study (>20 d since last visit)4 (2.5)0
Missed work, n (%)
Prior to study (>20 d in last 12 mo)012 (22.2)
During study (>20 d since last visit)04 (9.5)
TABLE 2.

Clinical Complications and Treatment Patterns in Pediatric vs Adult Pts with SCD at 3 Y

ACS, acute chest syndrome

*P<0.05

†P<0.01

‡P<0.0001

µUp to 3 discharge diagnoses may be listed for any hospital admission

Disclosures Heeney: Novartis: Research Funding. Adams-Graves: Novartis Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau. Paley: Novartis Pharma: Employment. Esposito: Novartis Pharma: Employment. McNamara: Novartis Pharmaceuticals Corporation: Employment. Vichinsky: Novartis : Consultancy, Research Funding, Speakers Bureau.

  • * Asterisk with author names denotes non-ASH members.