This is a long-term evaluation follow-up study of neurocognitive performance and emotional state in patients with chronic hepatitis C infection and a former (peg)interferon alfa-2b-based therapy.
M.R. Kraus, G. Teuber, NN, NN (MPsych), M. Scheurlen
Questions:
- Neurocognitive and psychiatric changes induced by interferon alfa-2b therapy in patients with chronic hepatitis C - are they fully reversible in long-term follow-up after the end of antiviral treatment?
- At least 12 months after the end of antiviral treatment - are neurocognitive and mood-related parameters even significantly improved as compared to pretreatment values? Is this possibly only true of patients with successful virus eradication?
- At least 12 months after the end of antiviral treatment, is there a significant difference between patients with and without sustained virological response with respect to neurocognitive performance, emotional state and quality of life?
- Can the results of the current and previous studies be confirmed by alternative / additional psychometric instruments in specified subsample? (Fatigue Impact Scale; FIS-D, SF-36)
- In the absence of clinically significant liver damage in patients with chronic hepatitis C - does the mere presence of the hepatitis C virus have any significant influence on neurocognitive or attentional performance?
- Does the study data support an additional indication for antiviral therapy in chronic hepatitis C? In the case of successful virus eradication, is emotional state and - above all - neurocognitive performance significantly improved even in the absence of severe liver damage?
Methods:
- Multifactorial analysis of test results: pre- vs. post-therapy; sustained virological response vs. nonresponse/relapse.
- Psychometric evaluation instruments / psychometric questionnaires (HADS-D, SCL-90-R, Subsample : SF-36, FIS-D)
- Evaluation of neurocognitive performance by the Test battery of Attentional Performance (TAP)
- Evaluation in a prospective, longitudinal study design.
Planned sample size / sample size considerations
- N = 150 patients (hepatitis C patients in a longitudinal study design: t1[before onset of interferon therapy] … t5[at least 12 months after the end of antiviral treatment]
Power calculations / power considerations:
- Given: 2-factorial design (time course x SVR); type I error = 0.050; type II error = 0.20 (power = 0.80) - as usually assumed in clinical trials.
- With respect to the independent factor SVR ("sustained virological response", 2 factor levels), optimum / optimal sample sizes range from 42 (large effect size d = 0.8) to 102 (medium effect size d = 0.5). Smaller effect sizes - according to previous work in this field - do not appear to bear any clinical relevance.
- (Pairwise comparisons of dependent samples [e.g. pre- vs. post-therapy or pre-therapy vs. long-term follow-up] require even smaller optimal sample sizes ranging from 16 to 43 for large or medium effect sizes.)
Patient recruitment:
- Patients with chronic hepatitis C infection and therapy with (peg)interferon alfa-2b.
- Patients with informed written consent (with respect) to a long-term follow-up of psychiatric side effects and neurocognitive performance.
- Patients with baseline monitoring of neuropsychiatric symptoms and neurocognitive performance.