Do we measure the right end points? A systematic review of primary outcomes in recent neonatal randomized clinical trials

Objectives: We performed a systematic review of primary outcomes in recently published neonatal randomized clinical trials to determine what end points are chosen for the evaluation of therapies in newborn infants. Methods: MEDLINE was searched in May 1998 for neonatal RCTs that had been published since 1993 in the British Medical Journal, The Journal of primary outcome was identified wherever possible. Continuous measures were distinguished. from discrete outcome events. The latter were classified as "long-term" if they were ascertained at least 6 months after birth. The hypothesized relative risk reduction for primary outcome event rates was calculated, where possible. Results: Of 119 eligible reports, 91 had an identifiable primary outcome that was a continuous measure in 46 trials and a discrete event in 45 trials. The median relative risk reduction was 50% for 28 of 40 short-term trials and 40% for 3 of 5 long-term trials. Conclusions: Most authors of recently published neonatal RCTs in 5 high-profile journals either failed to specify a primary end point or chose a continuous outcome measure. Trials with a discrete primary outcome were often short-term and designed to detect large risk reductions. Therefore modest but important treatment effects were likely missed by many of these trials.