Table 3.

Structural Validity of the HIT-6, PROMIS short forms, and HCV-PRO (N=961)

Measure	Items	Factor Loadingsa	RMSEAb	ECVc
HIT-6 scored	6	0.86 – 0.97	0.06	---e
PROMISd
Fatigue	7	0.30f, 0.76 – 0.91	0.04	--- e
Pain Interference	8	0.95 – 0.98	0.09	0.96
Sleep Disturbance	8	0.84 – 0.92	0.08	0.86
Depression	8	0.90 – 0.96	0.05	0.96
Cognitive Concerns	8	0.90 – 0.96	0.07	0.98
Anger	5	0.88 – 0.92	0.06	0.96
Anxiety	4	0.89 – 0.93	0.05	0.96
Belly Pain	6	0.93 – 0.98	0.05	0.99
Diarrhea	6	0.83 – 0.98	0.07	0.87
Nausea/Vomiting	4	0.66g, 0.84 – 0.96	0.05	--- e
HCV-PROh	16	0.55i, 0.67j, 0.71 – 0.86	0.04	0.82

Note:

^aFactor loadings obtained from the unidimensional confirmatory factor analysis. Factor loadings >0.70 support unidimensionality.

^bRMSEA=Root Mean Square Error Approximation. RMSEA values ≤ 0.06 indicate good fit, values ≤ 0.08 are fair, and values above 0.10 generally reflect poor fit. Statistics were based on full marginal tables. Model-based weight matrix was used.

^cECV=Expected Common Variance. ECV represents the variance explained by the general factor in the bifactor model. ECV > 0.90 support unidimensionality.

^dHigher values of HIT-6 and PROMIS T-scores indicate more severe symptoms.

^eUnidimensionality was assessed using a one-factor confirmatory factor analysis.

^fFactor loading of the item: “In the past 7 days, how often did you have enough energy to exercise strenuously?”.

^gFactor loading of the item: “In the past 7 days, how often did you have a poor appetite?”.

^hShown for reference in examining the properties of the HIT-6 and PROMIS scores. Higher values of HCV-PRO score indicate higher functional well-being..

^IFactor loading of the item: “Having Hepatitis C affected my sex life”.

^jFactor loading of the item: “Having Hepatitis C was very stressful to me”.