Four RCTs (95 participants), one before-and-after study (12 participants) and 3 historically-controlled studies (185 participants) were included.
When the 4 RCTs were pooled, the relative response rate of augmentation therapy with T3 was 1.53 (95% confidence interval, CI: 0.70, 3.35, p=0.29), compared with control. The mean decrease in HRS-D score was 0.60 (p= 0.001). Inter-trial heterogeneity was significant.
When the trials were combined regardless of methodology, the relative response rate of augmentation therapy with T3 was 2.09 (95% CI: 1.31, 3.32, p=0.002), compared with control. The mean decrease in HRS-D score was 0.62 (p<0.001). Inter-trial heterogeneity was significant.
The 5 studies that included assessment of side-effects reported no significant differences between T3 groups and controls.