Protocol for an open-label feasibility study for a randomised controlled trial of vitamin D supplementation in Crohn’s Disease patients with vitamin D deficiency: D-CODE Feasiblity study

Table 1 Participant pathway and timeline and interventions

Procedures	Routine Crohn's out-patient appointment	Telephone contact 1 week	Feasibility trial visits					Telephone and postal
	Routine Crohn's out-patient appointment	Telephone contact 1 week				Follow-up visit 1 12 weeks ± 7 days	Follow-up visit 2 24 weeks ± 14 days	Follow-up visit 3 28 weeks ± 14 days
	Vitamin D screening		Baseline	Eligibility	Randomisation	Intervention phase		Final follow-up
Informed consent	X		X
Demographics	X
Medical history including current medication list	X		X
Confirmation of eligibility	X			X
Vitamin D dried blood spot test	X
Answer lifestyle and food frequency questions	X							X
Telephone contact to arrange baseline appointment for feasibility trial		X
Randomisation					X
Pregnancy test as applicable			X
Blood tests:
Vitamin D (25(OH)D)			X			X	X
Calcium			X			X	X
Parathyroid hormone			X			X	X
Albumin			X			X	X
C-reactive protein			X			X	X
Iron studies			X			X	X
Ferritin			X			X	X
Full blood count			X			X	X
Hepcidin			X			x	X
Vitamin D metabolites			X			X	X
Height			X
Weight			X			X	X
Stool sample for faecal calprotectin ^a					x		x
PROM 1 IBDQ					X		X
PROM 2 EQ-5D-5L					X		X
Clinical Assessment 3 CDAI					X	X	X
Adverse event/reaction assessments						X	X	X
Dispensing of trial medication					X	X
Review of treatment diary						X	X
Compliance (pill count)						X	X
Assessment 4 Closing participant experience questionnaire - postal								X

^aIf a faecal calprotectin sample has been taken by the participants of the clinical team within the previous month, a further sample is not required for the study. The clinical result can be used.

ISSN: 2055-5784