Post Hoc Analysis
A statistical analysis of clinical trial data that was not specified in the original protocol, conducted after the study results are known. Post hoc analyses are exploratory and hypothesis-generating rather than confirmatory. They may identify unexpected treatment effects but carry a higher risk of false positive findings.
Technical Context
Post hoc analyses are conducted after unblinding and examining results — the knowledge of which treatments succeeded biases which questions are asked. This creates multiplicity concerns: testing many hypotheses increases the probability of finding false positives by chance. Post hoc results should be considered hypothesis-generating rather than confirmatory. They require confirmation in prospective, pre-specified analyses (either in new trials or in pre-registered analyses of existing data). Notable post hoc analyses in peptide therapeutics: subgroup analyses of CVOT data by baseline characteristics (which patient subgroups benefit most from GLP-1 RA cardiovascular protection?), and exploratory analyses of body composition changes with weight management therapies. Post hoc findings can guide Phase IV trial design and inform future research directions.