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Table 1 Description of studies

From: The risks and rewards of covariate adjustment in randomized trials: an assessment of 12 outcomes from 8 studies

Study Disease area Study type Sample size Outcome measure Outcome type Prognostic covariates
AUGIB Acute upper gastrointestinal bleeding Observational study 600a Mortality in hospital Binary (1) clinical Rockall score
Further bleeding in hospital Binary (1) clinical Rockall score
RBC transfusion in hospital Binary (1) presence of shock; (2) haemoglobin concentration at baseline
FASTER Postoperative rehabilitation RCT 316 Oswestry disability index Continuous (1) Oswestry disability index at baseline; (2) type of surgery
MIST2 Malignant pleural effusion RCT 210 Size of the patient’s pleural effusion at 7 days Continuous (1) size of the pleural effusion at baseline; (2) hospital-acquired infection; (3) large tube size; (4) drain present
Need for surgery at 90 days Binary (1) size of the pleural effusion at baseline; (2) large tube size
MOSAIC Sleep apnoea RCT 391 Epworth Sleepiness Score Continuous (1) Epworth Sleepiness Score at baseline; (2) sex; (3) MRI received at baseline
PBC Primary biliary cirrhosis RCT 312 Time to death Time-to-event (1) age; (2) albumin concentration; (3) bilirubin concentration; (4) histological stage
PROGRAMS Extremely preterm, small for gestational age neonates RCT 280 Sepsis-free survival up to day 14 Binary (1) gestational age at birth; (2) birth weight
Mortality up to day 14 Binary (1) gestational age at birth; (2) birth weight
RE01 Metastatic renal carcinoma RCT 347 Time to death Time-to-event (1) WHO score; (2) tumour grade; (3) white cell count
TIME2 Malignant pleural effusion RCT 106 Mean breathlessness over 42 days Continuous (1) breathlessness at baseline; (2) performance status; (3) mesothelioma
  1. aThis dataset contained 6,750 patients; however, when assessing this study, we set the sample size to 600 patients to make this more realistic to a trial setting. We chose 600 as this was the median sample size found among trials with a binary primary outcome in a recent review[12]. RCT, randomized controlled trial.