Randomized phase 2 trial of monthly vitamin D to prevent respiratory complications in children with sickle cell disease.

In sickle cell disease, respiratory infection and asthma may lead to respiratory complications that are a leading cause of morbidity and mortality. Vitamin D has anti-infective and immunomodulatory effects that may decrease the risk for respiratory infections, asthma, and acute chest syndrome. We conducted a randomized double-blind active-controlled clinical trial to determine whether monthly oral vitamin D3 can reduce the rate of respiratory events in children with sickle cell disease. Seventy sickle cell subjects, ages 3-20 years, with baseline records of respiratory events over 1 year before randomization, underwent screening. Sixty-two subjects with 25-hydroxyvitamin D levels of 5-60 ng/mL were randomly assigned to oral vitamin D3 (100 000 IU or 12 000 IU, n = 31 each) under observed administration once monthly for 2 years. The primary outcome was the annual rate of respiratory events (respiratory infection, asthma exacerbation, or acute chest syndrome) ascertained by the use of a validated questionnaire administered biweekly. Analysis included 62 children (mean age of 9.9 years, 52% female, and predominantly with homozygous HbS disease [87%]) with mean baseline 25-hydroxyvitamin D of 14.3 ng/mL. The annual rates of respiratory events at baseline and intervention years 1 and 2 were 4.34 ± 0.35, 4.28 ± 0.36, and 1.49 ± 0.37 (high dose) and 3.91 ± 0.35, 3.34 ± 0.37, and 1.54 ± 0.37 (standard dose), respectively. In pediatric patients with sickle cell disease, 2-year monthly oral vitamin D3 was associated with a >50% reduction in the rate of respiratory illness during the second year (P = .0005), with similar decreases associated with high- and standard-dose treatment. This trial was registered at www.clinicaltrials.gov as #NCT01443728.

Pain and other non-neurological adverse events in children with sickle cell anemia and previous stroke who received hydroxyurea and phlebotomy or chronic transfusions and chelation: results from the SWiTCH clinical trial.

To compare the non-neurological events in children with sickle cell anemia (SCA) and previous stroke enrolled in SWiTCH. The NHLBI-sponsored Phase III multicenter randomized clinical trial stroke with transfusions changing to hydroxyurea (SWiTCH) (ClinicalTrials.gov NCT00122980) compared continuation of chronic blood transfusion/iron chelation to switching to hydroxyurea/phlebotomy for secondary stroke prevention and management of iron overload. All randomized children were included in the analysis (intention to treat). The Fisher's Exact test was used to compare the frequency of subjects who experienced at least one SCA-related adverse event (AE) or serious adverse event (SAE) in each arm and to compare event rates. One hundred and thirty three subjects, mean age 13 ± 3.9 years (range 5.2-19.0 years) and mean time of 7 years on chronic transfusion at study entry, were randomized and treated. Numbers of subjects experiencing non-neurological AEs were similar in the two treatment arms, including SCA-related events, SCA pain events, and low rates of acute chest syndrome and infection. However, fewer children continuing transfusion/chelation experienced SAEs (P = 0.012), SCA-related SAEs (P = 0.003), and SCA pain SAEs (P = 0.016) as compared to children on the hydroxyurea/phlebotomy arm. The timing of phlebotomy did not influence SAEs. Older age at baseline predicted having at least 1 SCA pain event. Patients with recurrent neurological events during SWiTCH were not more likely to experience pain. In children with SCA and prior stroke, monthly transfusions and daily iron chelation provided superior protection against acute vaso-occlusive pain SAEs when compared to hydroxyurea and monthly phlebotomy.