Drury 2008.

Study characteristics
Methods	RCT. Parallel design. Duration: 1 month. Location: Montreal Children's Hospital Cystic Fibrosis Clinic, Canada. Date not specified.
Participants	Randomised: n = 14; 8 to 18 years, gender unspecified. Inclusion criteria CF with pancreatic insufficiency; method of CF diagnosis unreported Exclusion criteria known liver disease (diagnosed by ultrasound, liver function tests and/or hepatomegaly) supplemental therapeutic vitamin K to treat coagulopathies Withdrawal or loss to follow‐up: missing data (1) from 5 mg group at final assessment.
Interventions	Intervention: oral administration of injectable formulation of vitamin K1 phytonadione (Sandoz Canada, Boucherville, Qc) diluted 1 mg/1 mL; dose 1 mg/day for 1 month. Control: oral administration of injectable formulation of vitamin K1 phytonadione (Sandoz Canada, Boucherville, Qc) diluted 1 mg/1 mL; dose 5 mg/day for 1 month.
Outcomes	Primary outcomes: none reported Secondary outcomes plasma vitamin K1 levels serum undercarboxylated osteocalcin levels Measured at the beginning of the trial and at the end of 1 month.
Notes	This project was funded by the Canadian CF Foundation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "were randomised to receive either 1 mg/day, or 5 mg/day" Page 458. Comment: insufficient information to make a clear judgement of 'Yes' or 'No'.
Allocation concealment (selection bias)	Unclear risk	Not reported. Probably not done.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Participants: not reported. Healthcare providers: unclear. Outcomes assessors and data analysts: unclear. Comment: overall judgement unclear.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote "One subject in the 5 mg group lost consciousness at the time of the second blood procurement". Page 458. Comment: incomplete data for one participant.
Selective reporting (reporting bias)	Low risk	The stated objectives of the trial appear to match the listed outcomes. There was no evidence of selective reporting of outcomes.
Other bias	Unclear risk	Quote: "This project was funded by the Canadian CF Foundation". Comment: it is unclear to what extent the support provided may have had on the results of this trial. Insufficient information to assess whether an important risk of bias exists.