Table 5.

Summary of the Important Common Issues for LTFU and Guidance in Conducting Trials and Reporting Trial Results

Issues That Should Be Noted	Guidance
Inadequate or unclear allocation concealment	If allocation concealment forms part of the trial design, then effective approaches to achieve allocation concealment include using a matched placebo (visually identical to the active treatment); central randomization (performed at a site remote from the trial's location); sequentially numbered, sealed, opaque envelopes3
Large sample size and long follow up duration	LTFU increases with larger trial sample size, hence investigators should be aware and mitigate the number of LTFU for increase in sample size and 1‐y increase in duration
Reporting of LTFU	Investigators should strive to reduce the number of LTFU. A CONSORT diagram should be included for readers. When LTFU has occurred, baseline characteristics, and extent of follow up duration before exclusion should be reported in the manuscript or supplement. The implications of LTFU should also be discussed in the manuscript. Time of dropout can be noted on a supplement or in the result paragraph or on the CONSORT diagram for readers to know the extent of follow up before dropout

CONSORT indicates Consolidated Standards of Reporting Trials; LTFU, loss to follow‐up.