Table 1 Reanalysis of the number of units of red blood transfused in the Trial in Gastrointestinal Transfusion (TRIGGER) trial
Analysis method | Is the analysis method appropriate for use with a small or medium number of clusters? | Difference in meansa (95 % CI) | P value |
|---|---|---|---|
Unadjusted for clustering | No | −0.7 (−1.1 to −0.4) | <0.001 |
GEE (no correction) | No | −0.7 (−1.2 to −0.2) | 0.01 |
Mixed-effects model (no correction) | No | −0.7 (−1.2 to −0.2) | 0.01 |
GEE (with correction) | Yes | −0.7 (−1.8 to 0.4) | 0.15 |
Mixed-effects model (with correction) | Yes | −0.7 (−1.4 to 0.0) | 0.04 |
Cluster-level analysis | Yes | −0.7 (−1.6 to 0.3) | 0.12 |