Table 1

Statistical analysis plan

Research objectives	Outcome	Covariates	Analytical approach
To determine incidence of diarrhoea and consistency of bowel movements during critical illness To determine the frequency of diarrhoea defined as the proportion of patients with new ICU-acquired diarrhoea	Primary outcome	NA	The incidence of diarrhoea will be computed as the number of new cases during ICU stay divided by the person-time at risk. Descriptive statistics (proportion of patients with diarrhoea) and corresponding 95% CI
	WHO-defined diarrhoea
	Different definitions of primary outcome
	Bristol Stool Chart-defined diarrhoea
	Bliss Stool Classification System-defined diarrhoea
To determine risk factors associated with diarrhoea during critical illness	Primary outcome	Age, sex, APACHE II score, drugs (motility modifiers, opiates, stool softeners), prior gastrointestinal disease, centre	Logistic regression
	Dependent variable
	WHO-defined diarrhoea
Secondary outcomes
Research objective	Secondary outcome	Covariates	Analytic approach
To determine the consequences of diarrhoea	Dependent variable	WHO-defined diarrhoea, age, sex, APACHE II score	Cox regression
	Time to ICU discharge
	Time to hospital discharge
	Mortality		Logistic regression
Research objective	Secondary outcome	Covariates	Analytical approach
To determine the incidence of Clostridium difficile-associated diarrhoea (CDAD) during critical illness	IDSA-defined CDAD	NA	Descriptive statistics (proportion of cases with diarrhoea during study period)
	ESCMID-defined CDAD
	ACG-defined CDAD
To determine agreement between WHO and Bristol and Bliss scores	Chance corrected agreement (kappa score)	NA	Kappa statistic with 95% CI

APACHE II, Acute Physiology and Chronic Health Evaluation II; ACG, American College of Gastroenterology ; ESCMID, European Society of Clinical Microbiology and Infectious Diseases ; ICU, intensive care unit; IDSA, Infectious Disease Society of America ; NA, not applicable; CDAD, Clostridium-difficile associated diarrhoea.