The CIPRUS study, a nurse-led psychological treatment for patients with undifferentiated somatoform disorder in primary care: study protocol for a randomised controlled trial

Table 2 Overview of assessment moments and outcome measurements

	Instrument	Baseline (T0)	2 months (T1)	4 months (T2)	8 months (T3)	12 months (T4)
Primary outcomes
Physical functioning	PCS of RAND-36	x	x	x		x
Direct and indirect costs	Tic-P	x		x	x	x
Quality of life	EQ-5D-5L	x	x	x	x	x
Secondary outcomes
HRQoL	RAND-36 subscales	x	x	x		x
Anxiety and depression	HADS	x	x	x		x
Number/severity of symptoms	PHQ-15	x	x	x		x
Potential mediators
Health anxiety	Whitely Index	x	x	x
Illness perceptions	Brief IPQ	x	x	x
Cognitions and coping	CBRQ	x	x	x
Social problem-solving skills	SPSI-R:S	x	x	x
Mastery	Pearlin Mastery Scale	x	x	x
Working alliance	WAI-SF^a		x	x

PCS physical component summary score, RAND-36 RAND-36-item Health Survey, Tic-P Trimbos and iMTA questionnaire on Costs associated with Psychiatric Illness, EQ-5D-5L EuroQol 5D – 5 level version, HRQoL health-related quality of life, HADS Hospital Anxiety and Depression Scale, PHQ-15 Patient Health Questionnaire somatization scale, IPQ Illness Perception Questionnaire, CBRQ Cognitive and Behavioural Responses Questionnaire, SPSI-R:S Social Problem-solving Inventory Revised: Short Form, WAI-SF Working Alliance Inventory-Short Form
^aonly administered in the intervention group