Antithrombin for respiratory distress syndrome in preterm infants.
BACKGROUND
Acquired Antithrombin (AT) deficiency is a common and prognostically important finding in sick preterm infants with respiratory distress syndrome (RDS). It has been hypothesised that AT concentrate may improve clinical outcomes in preterm infants with RDS.


OBJECTIVE
To determine whether the administration of AT concentrate decreases mortality in preterm infants with RDS compared with placebo or no treatment.


METHODS
An electronic literature search in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE in August 2006 was performed. No language restriction was applied. References from identified studies were cross-checked for possible additional studies. Experts in the field and pharmaceutical companies were contacted for unpublished data. Abstracts of the American Society of Pediatric Research and European Society of Pediatric Research meetings (1983-2005) were searched and authors of relevant studies were contacted to obtain additional information.


METHODS
Randomized controlled trials comparing any dose and duration of AT therapy with placebo or no treatment in preterm infants with RDS.


METHODS
Two reviewers independently extracted data from included studies regarding mortality, intraventricular hemorrhage, mechanical ventilation, and other reported events in the clinical course of the patients. Data for similar outcomes were combined where appropriate, using a fixed-effects model in MetaView 4.2 (Update Software).


RESULTS
Two trials consisting of 182 preterm infants, fulfilled the inclusion criteria. Mean gestational age of patients included was 28 weeks. In one trial, patients had to be intubated and ventilated for RDS to be eligible for the study. In the other trial, RDS was not mentioned as an inclusion criteria, however the vast majority of infants in the study received surfactant. No individual trial showed a significant difference in mortality. One of the trials was stopped early because of an increase in deaths in the AT group. The pooled analysis for mortality within the first week of life showed a typical relative risk of 2.67 (95% CI 0.72-9.83) in favour of the control group. Only the trial that was stopped early followed the infants long enough to report neonatal mortality. This trial reported 7 deaths (11.5%) in the AT group and two deaths (3.3%) in the placebo group within 28 days of life. Secondary outcomes included days of mechanical ventilation and supplemental oxygen which were only reported in 1 trial. Both outcomes were in favour of the control group and statistically significant (p < 0.05).


CONCLUSIONS
Preterm infants with RDS are unlikely to benefit from AT treatment and may be harmed.
Bassler
D
D
McMaster University Medical Center, Department of Pediatrics/NICU, Room 4G40, 1200 Main Street West, Hamilton, Ontario, Canada. dirkbassler@hotmail.com
Millar
D
D
Schmidt
B
B
D000925:Anticoagulants / Q000627:therapeutic use*; D000990:Antithrombin III / Q000627:therapeutic use; D000991:Antithrombins / Q000627:therapeutic use*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011663:Pulmonary Surfactants / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy* / Q000401:mortality
D000925:Anticoagulants; D000991:Antithrombins; D011663:Pulmonary Surfactants; D000990:Antithrombin III