Chronic fatigue is associated with increased disease-related worries and concerns in inflammatory bowel disease

Table 1 Main characteristics of the questionnaires used in this study

Questionnaire	Number of items and dimensions	Main characteristics
SF-36 Ware et al[11]	36 items, divided into 8 dimensions	Measure generic HRQoL Scale scores from 0-100, with higher scores indicating better HRQoL
N-IBDQ Bernlev et al[17]	32 items, divided into 5 dimensions	Measure disease-specific HRQoL Scale scores from 32-224, with higher scores indicating better HRQoL
FQ Chalder et al[14] Jelsness-Jørgensen et al[10]	11 items, divided into 2 dimensions The FQ contains 2 items asking about duration and extent of fatigue symptoms	Measure both physical and mental fatigue Scale scores from 0-33 with higher scores indicating higher levels of fatigue In addition scored as a dichotomized scale where original scores 0 + 1 = 0 and 2 + 3 = 1 Chronic fatigue defined as a score of ≥ 4 on the dichotomized scale and duration of fatigue symptoms ≥ 6 mo
RFIPC Drossman et al[7]	25 items, divided into 6 dimensions	Measure the 25 most frequently reported disease-related worries/concerns by IBD patients

IBD: Inflammatory bowel disease; SF-36: Short-Form 36; N-IBDQ: IBD questionnaire (Norwegian version); FQ: Fatigue questionnaire; RFIPC: Rating form of IBD patient concerns; HRQoL: Health-related quality of life.