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Table 2 Dictionary of items to be extracted from included studies, with description and rationale

From: Blood pressure reduction and clinical outcomes with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers: protocol for a systematic review and meta-regression analysis

Data item Description and rationale
Study characteristics
 Study ID Unique identifier for each study retrieved.
 Trial acronym/first author Either the trial acronym (if applicable, e.g. HOPE, VALUE) or first author of the primary study report if not (e.g. Smith AB et al.).
 Year Year of primary study publication.
 Study design Placebo-controlled, active comparator-controlled or PROBE design.
 Duration of follow-up Time period (in months) over which participants underwent follow-up
 Age Mean age of all patients included in analysis.
 Sex Number (%) of male study participants.
 Hypertension Number (%) of study participants with hypertension.
 Heart failure Number (%) of study participants with heart failure.
 Diabetes Number (%) of study participants with diabetes.
 Ischaemic heart disease Number (%) of study participants with ischaemic heart disease.
 Loss to follow-up Number (%) of study participants lost to follow-up
 Revascularisation Number (%) of study participants that underwent invasive coronary revascularisation
 Concomitant drug therapy Number (%) of study participants receiving other cardiovascular agents (β-blockers, calcium channel blockers, etc.)
Exposures and outcomes for each group
 Group class Class of agent in the intervention and comparator arms (i.e. ACEi or ARB and placebo or active comparator).
 Group agent Identity of agent given to participants randomised to the intervention and comparator arms
n in group Number in intervention and comparator arms (included in final analysis)
 Baseline SBP Baseline systolic blood pressure (mmHg) in each group. If multiple are provided (e.g. sitting, ambulatory, supine, etc.) sitting/clinic measurement will be used.
 Follow-up SBP Systolic blood pressure measured during follow-up in each group (mmHg). Any SBP measured at ‘steady-state’ during follow-up, or SBP averaged across visits may be included. If serial measurements are reported, the last measurement will be extracted. SBP after the first-dose of the medication will not be included.
 Within-group difference in SBP The within-group change in SBP from baseline to follow-up either directly reported or calculated as per Fig. 2. Directly reported differences will supersede calculated values.
 Between-group difference in SBP The between-group difference in SBP change, either directly reported or calculated as per Fig. 2. Directly-reported differences will supersede calculated values.
 Baseline DBP Baseline diastolic blood pressure (mm Hg) in each group. If multiple are provided (e.g. sitting, ambulatory, supine, etc.) sitting/clinic measurement will be used.
 Follow-up DBP Diastolic blood pressure measured during follow-up in each group (mm Hg). Any DBP measured at ‘steady-state’ during follow-up, or SBP averaged across visits may be included. If serial measurements are reported, the last measurement will be extracted. DBP after the first-dose of the medication will not be included.
 Within-group difference in DBP The within-group change in DBP from baseline to follow-up either directly reported or calculated as per Fig. 2. Directly-reported differences will supersede calculated values.
 Between-group difference in DBP The between-group difference in DBP change either directly reported or calculated as per Fig. 2. Directly reported differences will supersede calculated values.
 All-cause mortality The total number of deaths, of any cause, that occur in each group during follow-up. If the denominator is different to ‘n in group’, this must be specified.
 Cardiovascular mortality The number of cardiovascular deaths that occur in each group during follow-up. If the denominator is different to ‘n in group’, this must be specified.
 Definition of cardiovascular mortality Study definition of cardiovascular mortality, as per Table 2, below.
 Myocardial infarction The number of myocardial infarctions that occur in each group during follow-up. If the denominator is different to ‘n in group’, this must be specified.
 Definition of myocardial infarction Study definition of cardiovascular mortality, as per Table 2, below.
 Stroke The number of strokes that occur in each group during follow-up. If the denominator is different to ‘n in group’, this must be specified.
 Definition of stroke Study definition of stroke, as per Table 2, below.
  1. Only data items for direct extraction are presented above. Calculation of group specific event rates, etc. will be performed during the analytic phase of the study. PROBE prospective randomised open-blinded end-point study design