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BackgroundDecisions to stop randomized trials are often based on traditional P value thresholds and are often unconvincing to clinicians. To familiarize clinical investigators with the application and advantages of Bayesian monitoring methods, we illustrate the steps of Bayesian interim analysis using a recent major trial that was stopped based on frequentist analysis of safety and futility.MethodsWe conducted Bayesian reanalysis of a factorial trial in newborn infants with hypoxic-ischemic encephalopathy that was designed to investigate whether outcomes would be improved by deeper (32 °C) or longer cooling (120 h), as compared with those achieved by standard whole body cooling (33.5 °C for 72 h). Using prior trial data, we developed neutral and enthusiastic prior probabilities for the effect on predischarge mortality, defined stopping guidelines for a clinically meaningful effect, and derived posterior probabilities for predischarge mortality.ResultsBayesian relative risk estimates for predischarge mortality were closer to 1.0 than were frequentist estimates. Posterior probabilities suggested increased predischarge mortality (relative risk > 1.0) for the three intervention groups; two crossed the Bayesian futility threshold.ConclusionsBayesian analysis incorporating previous trial results and different pre-existing opinions can help interpret accruing data and facilitate informed stopping decisions that are likely to be meaningful and convincing to clinicians, meta-analysts, and guideline developers.Trial registrationClinicalTrials.gov NCT01192776 . Registered on 31 August 2010.

ImportanceHypothermia at 33.5°C for 72 hours for neonatal hypoxic ischemic encephalopathy reduces death or disability to 44% to 55%; longer cooling and deeper cooling are neuroprotective in animal models.ObjectiveTo determine if longer duration cooling (120 hours), deeper cooling (32.0°C), or both are superior to cooling at 33.5°C for 72 hours in neonates who are full-term with moderate or severe hypoxic ischemic encephalopathy.Design, setting, and participantsA randomized, 2 × 2 factorial design clinical trial performed in 18 US centers in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network between October 2010 and November 2013.InterventionsNeonates were assigned to 4 hypothermia groups; 33.5°C for 72 hours, 32.0°C for 72 hours, 33.5°C for 120 hours, and 32.0°C for 120 hours.Main outcomes and measuresThe primary outcome of death or disability at 18 to 22 months is ongoing. The independent data and safety monitoring committee paused the trial to evaluate safety (cardiac arrhythmia, persistent acidosis, major vessel thrombosis and bleeding, and death in the neonatal intensive care unit [NICU]) after the first 50 neonates were enrolled, then after every subsequent 25 neonates. The trial was closed for emerging safety profile and futility analysis after the eighth review with 364 neonates enrolled (of 726 planned). This report focuses on safety and NICU deaths by marginal comparisons of 72 hours' vs 120 hours' duration and 33.5°C depth vs 32.0°C depth (predefined secondary outcomes).ResultsThe NICU death rates were 7 of 95 neonates (7%) for the 33.5°C for 72 hours group, 13 of 90 neonates (14%) for the 32.0°C for 72 hours group, 15 of 96 neonates (16%) for the 33.5°C for 120 hours group, and 14 of 83 neonates (17%) for the 32.0°C for 120 hours group. The adjusted risk ratio (RR) for NICU deaths for the 120 hours group vs 72 hours group was 1.37 (95% CI, 0.92-2.04) and for the 32.0°C group vs 33.5°C group was 1.24 (95% CI, 0.69-2.25). Safety outcomes were similar between the 120 hours group vs 72 hours group and the 32.0°C group vs 33.5°C group, except major bleeding occurred among 1% in the 120 hours group vs 3% in the 72 hours group (RR, 0.25 [95% CI, 0.07-0.91]). Futility analysis determined that the probability of detecting a statistically significant benefit for longer cooling, deeper cooling, or both for NICU death was less than 2%.Conclusions and relevanceAmong neonates who were full-term with moderate or severe hypoxic ischemic encephalopathy, longer cooling, deeper cooling, or both compared with hypothermia at 33.5°C for 72 hours did not reduce NICU death. These results have implications for patient care and design of future trials.Trial registrationclinicaltrials.gov Identifier: NCT01192776.

Aim In children with neonatal hypoxic-ischemic encephalopathy (HIE), we examined the association between 18-month functional status by parental report and disability at 6-7 years. Method Prospective observational study involving participants in the NICHD randomized controlled trial of hypothermia for HIE. Parent questionnaires-Functional Status-II (FS-II), Impact on Family (IOF) and Family Resource Scale (FRS) at 18 months were correlated with 6- to 7-year developmental assessments. Disability at 6-7 years was defined as IQ < 70, gross motor functional classification scale level III-V, bilateral blindness, deafness, or epilepsy. Results Rates of severe HIE (32 vs. 15%), public insurance (73% vs. 47%) and IOF scales were higher and mean (SD) FS-II independence (I) {54 (SD 35) vs. 98 (SD 8)} and general health (GH) {87 (SD 14) vs. 98 (SD 6)} scores were significantly lower in children with disability (n=37) at 6-7 years, compared to those (n=74) without disability. FS-II I scores were significantly associated with disability (OR 0.92; 95% CI 0.87-0.97; p=0.003). On path analysis, severe HIE, greater IOF and public insurance were associated with poorer 18-month FS-II I scores, which, in turn, were associated with disability at 6 to 7 years. Interpretation Poor independent functioning by parental report at 18 months in children with HIE was associated with childhood disability. [ABSTRACT FROM AUTHOR]

Objective The objective of our study was to examine the relationship between brain injury and outcome following neonatal hypoxic-ischaemic encephalopathy treated with hypothermia. Design and patients Neonatal MRI scans were evaluated in the National Institute of Child Health and Human Development (NICHD) randomised controlled trial of whole-body hypothermia and each infant was categorised based upon the pattern of brain injury on the MRI fi ndings. Brain injury patterns were assessed as a marker of death or disability at 18-22 months of age. Results Scans were obtained on 136 of 208 trial participants (65%); 73 in the hypothermia and 63 in the control group. Normal scans were noted in 38 of 73 infants (52%) in the hypothermia group and 22 of 63 infants (35%) in the control group. Infants in the hypothermia group had fewer areas of infarction (12%) compared to infants in the control group (22%). Fifty-one of the 136 infants died or had moderate or severe disability at 18 months. The brain injury pattern correlated with outcome of death or disability and with disability among survivors. Each point increase in the severity of the pattern of brain injury was independently associated with a twofold increase in the odds of death or disability. Conclusions Fewer areas of infarction and a trend towards more normal scans were noted in brain MRI following whole-body hypothermia. Presence of the NICHD pattern of brain injury is a marker of death or moderate or severe disability at 18-22 months following hypothermia for neonatal encephalopathy. INSETS: What is already known on this topic;What this study adds. [ABSTRACT FROM AUTHOR]

Data from the whole-body hypothermia trial was analyzed to examine the effects of phenobarbital administration prior to cooling (+PB) on the esophageal temperature (Te) profile, during the induction phase of hypothermia. A total of 98 infants were analyzed. At enrollment, +PB infants had a higher rate of severe hypoxic-ischemic encephalopathy and clinical seizures and lower Te and cord pH than infants that have not received phenobarbital (–PB). There was a significant effect of phenobarbital itself and an interaction between phenobarbital and time in the Te profile. Mean Te in the +PB group was lower than in the –PB group, and the differences decreased over time. In +PB infants, the time to surpass target Te of 33.5°C and to reach the minimum Te during overshoot were shorter. In conclusion, the administration of phenobarbital before cooling was associated with changes that may reflect a reduced thermogenic response associated with barbiturates. [ABSTRACT FROM AUTHOR]

It remains controversial as to whether neonatal seizures have additional direct effects on the developing brain separate from the severity of the underlying encephalopathy. Using data collected from infants diagnosed with hypoxic-ischemic encephalopathy, and who were enrolled in an National Institute of Child Health and Human Development trial of hypothermia, we analyzed associations between neonatal clinical seizures and outcomes at 18 months of age. Of the 208 infants enrolled, 102 received whole body hypothermia and 106 were controls. Clinical seizures were generally noted during the first 4 days of life and rarely afterward. When adjustment was made for study treatment and severity of encephalopathy, seizures were not associated with death, or moderate or severe disability, or lower Bayley Mental Development Index scores at 18 months of life. Among infants diagnosed with hypoxic-ischemic encephalopathy, the mortality and morbidity often attributed to neonatal seizures can be better explained by the underlying severity of encephalopathy. [ABSTRACT FROM AUTHOR]

Background: We previously reported early results of a randomized trial of whole-body hypothermia for neonatal hypoxic–ischemic encephalopathy showing a significant reduction in the rate of death or moderate or severe disability at 18 to 22 months of age. Long-term outcomes are now available. Methods: In the original trial, we assigned infants with moderate or severe encephalopathy to usual care (the control group) or whole-body cooling to an esophageal temperature of 33.5°C for 72 hours, followed by slow rewarming (the hypothermia group). We evaluated cognitive, attention and executive, and visuospatial function; neurologic outcomes; and physical and psychosocial health among participants at 6 to 7 years of age. The primary outcome of the present analyses was death or an IQ score below 70. Results: Of the 208 trial participants, primary outcome data were available for 190. Of the 97 children in the hypothermia group and the 93 children in the control group, death or an IQ score below 70 occurred in 46 (47%) and 58 (62%), respectively (P=0.06); death occurred in 27 (28%) and 41 (44%) (P=0.04); and death or severe disability occurred in 38 (41%) and 53 (60%) (P=0.03). Other outcome data were available for the 122 surviving children, 70 in the hypothermia group and 52 in the control group. Moderate or severe disability occurred in 24 of 69 children (35%) and 19 of 50 children (38%), respectively (P=0.87). Attention–executive dysfunction occurred in 4% and 13%, respectively, of children receiving hypothermia and those receiving usual care (P=0.19), and visuospatial dysfunction occurred in 4% and 3% (P=0.80). Conclusions: The rate of the combined end point of death or an IQ score of less than 70 at 6 to 7 years of age was lower among children undergoing whole-body hypothermia than among those undergoing usual care, but the differences were not significant. However, hypothermia resulted in lower death rates and did not increase rates of severe disability among survivors. (Funded by the National Institutes of Health and the Eunice Kennedy Shriver NICHD Neonatal Research Network; ClinicalTrials.gov number, NCT00005772.) [ABSTRACT FROM PUBLISHER]

0BJECTIVE. The goals were to identify predictor variables and to develop scoring systems and classification trees to predict death/disability or death in infants with hypoxic-ischemic encephalopathy. METHODS. Secondary analysis of data from the multicenter, randomized, controlled, National Institute of Child Health and Human Development Neonatal Research Network trial of hypothermia in hypoxic-ischemic encephalopathy was performed. Data for 205 neonates diagnosed as having hypoxic-ischemic encephalopathy were studied. Logistic regression analysis was performed by using clinical and laboratory variables available within 6 hours of birth, with death or moderate/severe disability at 18 to 22 months or death as the outcomes. By using the identified variables and odds ratios, scoring systems to predict death/disability or death were developed, weighting each predictor in proportion to its odds ratio. In addition, classification and regression tree analysis was performed, with recursive partitioning and automatic selection of optimal cutoff points for variables. Correct classification rates for the scoring systems, classification and regression tree models, and early neurologic examination were compared. RESULTS. Correct classification rates were 78% for death/disability and 71% for death with the scoring systems, 80% and 77%, respectively, with the classification and regression tree models, and 67% and 73% with severe encephalopathy in early neurologic examination. Correct classification rates were similar in the hypothermia and control groups. CONCLUSIONS. Among neonates diagnosed as having hypoxic-ischemic encephalopathy, the classification and regression tree model, but not the scoring system, was superior to early neurologic examination in predicting death/disability. The 3 models were comparable in predicting death. Only a few components of the early neurologic examination were associated with poor outcomes. These scoring systems and classification trees, if validated, may help in assessments of prognosis and may prove useful for risk-stratification of infants with hypoxic-ischemic encephalopathy for clinical trials. [ABSTRACT FROM AUTHOR]

Background: Hypothermia is protective against brain injury after asphyxiation in animal models. However, the safety and effectiveness of hypothermia in term infants with encephalopathy is uncertain. Methods: We conducted a randomized trial of hypothermia in infants with a gestational age of at least 36 weeks who were admitted to the hospital at or before six hours of age with either severe acidosis or perinatal complications and resuscitation at birth and who had moderate or severe encephalopathy. Infants were randomly assigned to usual care (control group) or whole-body cooling to an esophageal temperature of 33.5°C for 72 hours, followed by slow rewarming (hypothermia group). Neurodevelopmental outcome was assessed at 18 to 22 months of age. The primary outcome was a combined end point of death or moderate or severe disability. Results: Of 239 eligible infants, 102 were assigned to the hypothermia group and 106 to the control group. Adverse events were similar in the two groups during the 72 hours of cooling. Primary outcome data were available for 205 infants. Death or moderate or severe disability occurred in 45 of 102 infants (44 percent) in the hypothermia group and 64 of 103 infants (62 percent) in the control group (risk ratio, 0.72; 95 percent confidence interval, 0.54 to 0.95; P=0.01). Twenty-four infants (24 percent) in the hypothermia group and 38 (37 percent) in the control group died (risk ratio, 0.68; 95 percent confidence interval, 0.44 to 1.05; P=0.08). There was no increase in major disability among survivors; the rate of cerebral palsy was 15 of 77 (19 percent) in the hypothermia group as compared with 19 of 64 (30 percent) in the control group (risk ratio, 0.68; 95 percent confidence interval, 0.38 to 1.22; P=0.20). Conclusions: Whole-body hypothermia reduces the risk of death or disability in infants with moderate or severe hypoxic–ischemic encephalopathy. N Engl J Med 2005;353:1574-84. [ABSTRACT FROM AUTHOR]