Table 2. Subgroup analyses based on various exclusion criteria for the TDI focal score.

Outcome	n [N]	WMD (95% CI)	P value	I² (%)	P_{heterogeneity}
All included trials (9,10)	4,767 [4]	0.30 (0.14 to 0.46)	0.0003	28	0.24
Duration: 52 wk (9)	3,091 [2]	0.30 (0.11 to 0.49)	0.002	0	1.00
Duration: 24 wk (10)	1,676 [2]	0.30 (–0.09 to 0.69)	0.13	76	0.04
Monotherapy (9)	3,091 [2]	0.30 (0.11 to 0.49)	0.002	0	1.00
Combination therapy (10)	1,676 [2]	0.30 (–0.09 to 0.69)	0.13	76	0.04
Roflumilast + salmeterol (10) (M2-127)	933 [1]	0.10 (–0.17 to 0.37)	0.47	—	—
Roflumilast + tiotropium (10) (M2-128)	743 [1]	0.50 (0.23 to 0.77)	0.0003	—	—
Moderate to severe (10)	1,676 [2]	0.30 (–0.09 to 0.69)	0.13	76	0.04
Severe to very severe (9)	3,091 [2]	0.30 (0.11 to 0.49)	0.002	0	1.00

TDI, the transition dyspnea index; n, number of patients; N, number of trials; WMD, weighted mean difference.