A Bayesian re-analysis of the STRESS trial

Prophylactic steroids are often used to reduce the systemic inflammatory response to cardiopulmonary bypass in infants undergoing heart surgery. The STRESS trial found that the odds of a worse outcome did not differ between infants randomized to methylprednisolone (n = 599) versus placebo (n = 601) (adjusted odds ratio [OR], 0.86; P = .14). However, secondary analyses showed possible benefits with methylprednisolone. To investigate further using a different probabilistic approach, we re-analyzed the STRESS trial using Bayesian analytics.

We used a covariate-adjusted proportional odds model using the original STRESS trial primary endpoint, a ranked composite of death, transplant, major complication and post op length of stay. We performed Markov Chain Monte Carlo simulations to assess the probability of benefit (OR < 1) versus harm (OR > 1). Primary analysis assumed a neutral probability of benefit versus harm with weak prior belief strength (nearly noninformative prior distribution). To illustrate magnitude of effect, we calculated predicted risk of death, transplant or major complications for methylprednisolone and placebo. Sensitivity analyses evaluated pessimistic (5%-30% prior likelihood of benefit), neutral and optimistic (70%-95%) prior beliefs, and controlled strength of prior belief as weak (30% variance), moderate (15%) and strong (5%). A secondary analysis derived empirical priors using data from four previous steroid trials.

The posterior probability of any benefit from methylprednisolone was 92% and probability of harm was 8%. Composite death or major complication occurred in 18.8% of subjects with an absolute risk difference of -2% (95% CI -3%, +1%) for methylprednisolone. Each of 9 sensitivity analyses demonstrated greater probability of benefit than harm in the methylprednisolone group with 8 of 9 demonstrating >80% probability of benefit and ≥1% absolute difference in risk of death, transplant or major complications. In secondary analysis deriving priors from previous steroid trials, results were consistent with a 95% posterior probability of benefit.

Our Bayesian re-analysis of the STRESS trial, using a range of prior beliefs, demonstrated a high probability that perioperative methylprednisolone reduces the risk of death or major complications in infants undergoing cardiopulmonary bypass compared with placebo. This more in-depth analysis expands the initial clinical evaluation of methylprednisolone provided by the STRESS trial.

Clinicaltrials.gov: NCT03229538 (https://clinicaltrials.gov/study/NCT03229538).