Comparison 1. Systemic corticosteroids for 7 or fewer days vs longer than 7 days.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Treatment failure	4	457	Odds Ratio (M‐H, Fixed, 95% CI)	0.72 [0.36, 1.46]
2 Relapse	4	478	Odds Ratio (M‐H, Fixed, 95% CI)	1.04 [0.70, 1.56]
3 Time to re‐exacerbation	1		Hazard Ratio (Fixed, 95% CI)	Subtotals only
4 Adverse effect—hyperglycaemia	2	345	Odds Ratio (M‐H, Fixed, 95% CI)	0.99 [0.64, 1.53]
5 Adverse effect—hypertension	1		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
6 Other adverse effects—gastrointestinal tract bleeding, symptomatic gastrointestinal reflux, symptoms of congestive heart failure or ischaemic heart disease, sleep disturbance, fractures, depression	5	503	Odds Ratio (M‐H, Fixed, 95% CI)	0.89 [0.46, 1.69]
7 Mortality	2	336	Odds Ratio (M‐H, Fixed, 95% CI)	0.91 [0.40, 2.06]
8 Length of hospitalisation	3	421	Mean Difference (IV, Fixed, 95% CI)	‐0.61 [‐1.51, 0.28]
9 FEV1 (L) (early)	3	96	Mean Difference (IV, Fixed, 95% CI)	‐0.07 [‐0.19, 0.05]
9.1 FEV1 absolute	2	75	Mean Difference (IV, Fixed, 95% CI)	‐0.08 [‐0.22, 0.06]
9.2 FEV1 change	1	21	Mean Difference (IV, Fixed, 95% CI)	‐0.04 [‐0.27, 0.19]
10 FEV1 % predicted (6 days)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
11 FVC (L) (early)	3	97	Mean Difference (IV, Fixed, 95% CI)	0.01 [‐0.20, 0.22]
11.1 FVC measured	2	75	Mean Difference (IV, Fixed, 95% CI)	‐0.05 [‐0.29, 0.19]
11.2 FVC change from baseline	1	22	Mean Difference (IV, Fixed, 95% CI)	0.23 [‐0.23, 0.69]
12 FEV1 (L) end of treatment	4	187	Mean Difference (IV, Random, 95% CI)	‐0.04 [‐0.19, 0.10]
12.1 FEV1 measured	3	164	Mean Difference (IV, Random, 95% CI)	‐0.05 [‐0.25, 0.16]
12.2 FEV1 change from baseline	1	23	Mean Difference (IV, Random, 95% CI)	‐0.04 [‐0.23, 0.14]
13 FEV1 % predicted 30 days	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
14 FVC (L) end of treatment	3	99	Mean Difference (IV, Fixed, 95% CI)	‐0.12 [‐0.33, 0.09]
14.1 FVC measured	2	77	Mean Difference (IV, Fixed, 95% CI)	‐0.14 [‐0.39, 0.11]
14.2 FVC change from baseline	1	22	Mean Difference (IV, Fixed, 95% CI)	‐0.07 [‐0.44, 0.29]
15 PaO2 (mmHg) (early)	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
16 PaO2 (mmHg) end of treatment	2	121	Mean Difference (IV, Fixed, 95% CI)	‐1.38 [‐4.96, 2.21]
17 PaCO2 (mmHg)	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
17.1 3 days of follow‐up	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
17.2 10 days of follow‐up	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
18 Symptoms—dyspnoea (early)	2	320	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.08 [‐0.29, 0.14]
19 Symptoms—dyspnoea (15 days)	4	404	Std. Mean Difference (IV, Fixed, 95% CI)	0.16 [‐0.03, 0.36]
19.1 Change	3	133	Std. Mean Difference (IV, Fixed, 95% CI)	0.25 [‐0.09, 0.60]
19.2 Absolute	1	271	Std. Mean Difference (IV, Fixed, 95% CI)	0.12 [‐0.12, 0.36]
20 Quality of life—overall (6 days)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
21 Quality of life—overall (30 days)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only