Background: A non-completer is defined as a participant who leaves a trial before the end of the planned follow-up. Research in nursing homes is highly exposed to this problem because of high death rates.

Objective: To assess the statistical management of non-completers in cluster randomized trials carried out in nursing homes.

Study design and setting: A methodological review of published cluster randomized trial.

Results: We selected 37 articles. For 22 (59%) trials, the design was closed-cohort (i.e., participants included all at the same time when randomizing clusters). In those 22 closedcohort trials, the median follow-up was 6.5 months (interquartile range 4 to 12). The median non-completer rate was 19.5% and the median non-completions due to death was 73.2%. In only one trial were the baseline characteristics of completers and non-completers compared.

Strategies to deal with non-completers were an inflation of the planned sample size (11 trials), the use of repeated measurements of the outcome (12 trials) and the use of imputation methods when analyzing data (7 trials).

In cluster randomized trials of nursing homes, non-completers are managed as for any missing data, but they are essentially due to death. Methodological and statistical developments and guidance are needed.