The aim of this study is to assess agreement, smallest detectable change, and reliability of repeated measurements of liver stiffness of transient elastography in patients with chronic viral hepatitis, and to explore factors associated with disagreement.
Previous studies have reported excellent test-retest reliability for transient elastography (TE) in viral hepatitis. Reliability refers the ability of an instrument to discriminate between study subjects and may be excellent even if considerable measurement-error exists, if the population is heterogenous. Agreement, in contrast, refers to differences of measurements on the original scale (kPa for TE). Whether agreement is acceptable is situation-dependent and can be related to the smallest detectable change (SDC). Agreement metrics or SDC have not been addressed in previous studies for chronic viral hepatitis. The aim of this study is to assess agreement, SDC, and reliability of repeated measurements of liver stiffness of TE in patients with chronic viral hepatitis, and to explore factors associated with disagreement.
Study Type
OBSERVATIONAL
Enrollment
300
Transient elastography measures liver stiffness in kPa
Oskar Ljungquist
Helsingborg, Skåne County, Sweden
RECRUITINGDisagreement defined as a difference in TE results between operators in KPa of ≥ 33%, as well as the smallest detectable change, SDC95.
Disagreement, expressed as 1) the proportion of participants with inter-rater differences at or above our prespecified threshold (33%) and 2) the smallest detectable change, representing the difference needed to state with 95% certainty that a change had occurred in the underlying fibrosis (SDC95).
Time frame: Assessed at a 30 min visit to the outpatient clinic
Reliability, estimated using the intra-class correlation
Reliability, for continuous stiffness measurements as well as for different fibrosis stage categories.
Time frame: Assessed at a 30 min visit to the outpatient clinic
Patient and exam characteristics associated with inter-rater differences above our prespecefied threshold.
As an exploratory outcome, patient and exam characteristics associated with inter-rater differences above our prespecified threshold of ≥ 33% in liver stiffness will be evaluated. These characteristics include patients age, hepatitis b staging, BMI, biomarkers including Alanine transaminase, probe type, (medium or XL-probe) viral load, alkaline phosphatase, bilirubin, albumin, prothrombin time/international normalized ratio, time since food (hours), time since alcohol (hours), previous liver biopsy (years)
Time frame: Assessed at a 30 min visit to the outpatient clinic
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