Analysis of indications for selectively missing results in comparative registry-based studies in medicine: a meta-research study

We found that the results of registry-based studies might be selectively missing. Results from registry-based studies comparing medical interventions should be interpreted very cautiously, as positive findings could be a result from p-hacking, publication bias, or selective reporting. Prospective registration of such studies is necessary and should be made mandatory both in regulatory contexts and for publication in journals. Further research is needed to determine the main reasons for selectively missing results to support the development and implementation of more specific methods for preventing selectively missing results.