Comparison 2. Abatacept (2 mg/kg) + etanercept versus placebo + etanercept.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 ACR 20% improvement	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.1 6 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.58 [0.92, 2.71]
1.2 12 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.58 [0.92, 2.71]
2 ACR 50% improvement	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
2.1 6 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.33 [0.63, 2.83]
2.2 12 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.69 [0.76, 3.79]
3 ACR 70% improvement	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
3.1 6 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	8.17 [0.49, 136.81]
3.2 12 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.69 [0.38, 7.59]
4 Physical function (mHAQ, 0‐3 scale)	1	121	Mean Difference (IV, Fixed, 95% CI)	‐0.10 [‐0.27, 0.07]
5 Patient assessment of pain (100 mm VAS)	1	121	Mean Difference (IV, Fixed, 95% CI)	‐3.40 [‐14.86, 8.06]
6 Withdrawals due to adverse events ‐ 12 months	1	121	Peto Odds Ratio (Peto, Fixed, 95% CI)	2.94 [0.76, 11.34]
7 All withdrawals ‐ 12 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	0.82 [0.49, 1.37]
8 Serious infections ‐ 12 months	1	121	Peto Odds Ratio (Peto, Fixed, 95% CI)	4.25 [0.35, 51.61]
9 Upper respiratory infections ‐ 12 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.69 [0.69, 4.16]
10 Total adverse events ‐ 12 months	1	121	Risk Ratio (M‐H, Fixed, 95% CI)	1.05 [0.92, 1.19]
11 Total serious adverse events ‐ 12 months	1	121	Peto Odds Ratio (Peto, Fixed, 95% CI)	3.49 [1.08, 11.34]
12 Death ‐ 12 months	1		Peto Odds Ratio (Peto, Fixed, 95% CI)	Subtotals only