Markers of severe vaso-occlusive painful episode frequency in children and adolescents with sickle cell anemia

Objective: To identify factors associated with frequent severe vaso-occlusive pain crises in a contemporary pediatric cohort of patients with sickle cell anemia (SCA) enrolled in a prospective study of pulmonary hypertension and the hypoxic response in sickle cell disease. Study design: Clinical and laboratory characteristics of children with SCA who had ≥3 severe pain crises requiring health care in the preceding year were compared with those of subjects with <3 such episodes. Results: Seventy-five children (20%) reported ≥3 severe pain episodes in the preceding year, and 232 (61%) had none. Frequent pain episodes were associated with older age (OR, 1.2; 95% CI, 1.1-1.3; P <.0001), α-thalassemia trait (OR 3.5; 1.6-6.7; P =.002), higher median hemoglobin (OR 1.7; 95% CI: 1.2-2.4; P <.003), and lower lactate dehydrogenase concentration (OR 1.82; 95% CI: 1.07-3.11; P =.027). Children with high pain frequency also had an increased iron burden (serum ferritin, 480 vs 198 μg/L; P =.006) and higher median tricuspid regurgitation jet velocity (2.41 vs 2.31 m/s; P =.001). Neither hydroxyurea use nor fetal hemoglobin levels were significantly different according to severe pain history. Conclusions: In our cohort of children with SCA, increasing age was associated with higher frequency of severe pain episodes as were α-thalassemia, iron overload, higher hemoglobin and lower lactate dehydrogenase concentration, and higher tricuspid regurgitation velocity.