If a study is prematurely closed (for any number of reasons) and an analysis is not done, how should we record that in ClinicalTrials.gov? Does it matter if there are no subjects enrolled, vs. some subjects enrolled?

Trials that terminate prematurely must still indicate that the trial is closed via the “Enrollment Status” field and a brief explanation of why the study was terminated should be provided. If you collected data during the trial and the trial meets the definition of an applicable clinical trial, results must be reported on ClinicalTrials.gov. A good example of this is NCT00004500, which was terminated early.