Mukerji 2015.

Study characteristics
Methods	Study design: randomised, double‐blind, parallel‐group, placebo‐controlled trial Number of study centres and location: single centre; Palmerston North Hospital, New Zealand Study setting: emergency department (ED) Withdrawals: stated Date of study: July and October 2013
Participants	Number screened: 37 Number randomised: 33 Numbers in treatment group: 14 Number in placebo group: 19 Numbers of withdrawals: 1 (magnesium), 2 (placebo) Numbers completing trial: 13 (magnesium), 17 (placebo) Number included in analysis: 30 Mean age SD (years): 76.1 (SD 12.47) (magnesium), 72.9 (SD 9.39) (placebo) Gender (male/female): 11/2 (magnesium), 10/7 (placebo) Diagnostic criteria: clinically by the attending physician who was not one of the investigators Baseline lung function Mean FEV1 at presentation: 0.637 L (magnesium); 0.691 L (placebo) Number of participants with FEV1 at presentation < 50% of predicted: 13 (magnesium); 17 (placebo) Smoking history Mean amount of smoking (pack‐years): 40.0 (magnesium); 38.8 (placebo) Current smokers: 4 (magnesium); 5 (placebo) Never smokers: 1 (magnesium); 1 (placebo) Serum magnesium level (mmol/L) mean/SD: 0.79/0.1 (magnesium); 0.78/0.1 (placebo) Inclusion criteria: non‐infective and infective cases of AECOPD in people above the age of 35 years, who had a previously documented diagnosis of COPD by either their general practitioner or in‐hospital respiratory specialists Exclusion criteria: people requiring mechanical ventilation or NIV at presentation; anyone who was unable to do spirometry or had evidence of pneumothorax or hypotension or any other serious medical condition that would prevent their participation; responders or ‘asthma‐type’ COPD patients; those with a history of asthma.
Interventions	Intervention: 2 g IV magnesium sulphate made up to 20 mL in 0.9% sodium chloride solution (saline) + standard therapy Comparator: 20 ml of IV saline as placebo + standard therapy Concomitant medications 5 mg of nebulised salbutamol Standard therapy 5 mg salbutamol and 500 mcg ipratropium Bromide by jet nebulisation • 60 mg of oral prednisone or 100 mg of IV hydrocortisone • Oxygen: 2 L per min via nasal prongs if the patient’s pulse oximetry revealed saturations of < 90%
Outcomes	Primary outcomes percentage change in FEV1 and FVC at 0, 60 and 120 minutes Secondary outcomes: hospital admission; episodes of NIV/mechanical ventilation; length of stay.
Notes	Funding for studies: Midcentral District Health Board, Palmerston North, New Zealand. Conflicts of interest of trial authors: declared "nil" The trial was registered with Australian New Zealand Clinical Trials Registry: (ANZCTR) (ACTRN12613000837729).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The senior ED pharmacist performed block randomisation. A block size of 20 was used with a 1:1 allocation ratio"
Allocation concealment (selection bias)	Low risk	Quote: "The senior ED pharmacist provided identical numbered pre‐made syringes with either trial drug or placebo"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "The senior ED pharmacist provided identical pre‐made syringes with either trial drug or placebo, as per randomisation, to maintain investigator and patient masking"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: participants, investigators, outcome assessors were all masked.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: attrition rates were similar in both groups (7.1% vs 5.2%).
Selective reporting (reporting bias)	Low risk	Comment: trial was registered on website, all outcome measures were reported as planned.
Other bias	Low risk	Comments: no other apparent biases identified.