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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.