Poulsen 1999.

Study characteristics
Methods	Randomised clinical trial at a single site in Denmark between September 1993 and January 1995
Participants	77 participants with acute MI defined as creatinine kinase ≥ 210 IU and creatinine kinase B ≥ 20 IU or electrocardiographic evidence of MI (ST elevation > 1 mm in contiguous leads or subendocardial injury pattern) and typical chest pain were eligible for the study. Furthermore, all patients had LVEF > 40% at baseline and were between 40 and 75 years of age Male:female = 58:19 Mean age = 61.5 years Exclusion criteria: ongoing treatment with beta‐blockers, systolic blood pressure < 100 mmHg, heart rate < 50 beats/min, intermittent claudication, significant valvular heart disease, severe obstructive lung disease, appearance of atrioventricular block of second or third degree, uncontrolled diabetes mellitus, severe uncontrolled congestive heart failure, other life‐threatening disease
Interventions	Treatment begun 5 to 7 days after admission Experimental group: metoprolol 200 mg for 12 months (n = 39) Control group: placebo for 12 months (n = 38) Co‐intervention: none mentioned Excluded medication: none mentioned
Outcomes	Outcomes: cardiac mortality, ejection fraction, cardiovascular parameters Time points reported: 3, 6, and 12 months
Notes	Study authors were contacted at steepoul@rm.dk on 20‐06‐2017. No response was received Randomisation took place 5 to 7 days after admission with acute myocardial infarction Study reported only 'sudden cardiac mortality'; because no other deaths were reported, we used this as our all‐cause mortality MACE was not reported nor calculated because no data were available Study was funded by the Danish Heart Foundation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described sufficiently, other than "patients were randomly assigned to receive either metoprolol (200 mg) or placebo"
Allocation concealment (selection bias)	Unclear risk	Not described sufficiently, other than "patients were randomly assigned to receive either metoprolol (200 mg) or placebo"
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described; however, the study was described as double‐blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	"Echocardiographic data were analyzed by one author (S.H.P.) blinded to the patients’ clinical data" However, assessment of mortality was not described
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	It is not described whether any participants were lost to follow‐up. Only withdrawals were described
Selective reporting (reporting bias)	Unclear risk	No protocol was found; however mortality and serious adverse events were reported
Other bias	Low risk	No other biases were found