Tanaka 1996.

Methods	Generation of allocation sequence: unclear (no description). Allocation concealment: unclear (no description). Double blinding: inadequate (not blinding). Follow up: adequate (no information). Sample size calculation: no information. Intention‐to‐treat analysis: not performed.
Participants	Country: Japan. Type of hepatitis: chronic hepatitis C. INCLUSION CRITERIA ‐ serum HCV RNA positive at least three times. ‐ liver biopsy findings of chronic hepatitis. EXCLUSION CRITERIA ‐ previously received corticosteroid, immunosuppressive, UDCA or antiviral treatment; ‐ history of alcohol or drug abuse or evidence of metabolic or autoimmune disorders. PARTICIPANTS ‐ UDCA plus IFN group (n = 26): Mean age (years +/‐ SD) 53 +/‐ 10; Ratio of sex (M/F) 14/12. Proportion of patients with cholestasis: no information. Proportion of patients with cirrhosis: no information. ‐ IFN group (n =26): Mean age (years +/‐ SD) 49 +/‐ 10. Ratio of sex (M/F) 17/9. Proportion of patients with cholestasis: no information. Proportion of patients with cirrhosis: no information.
Interventions	UDCA plus IFN group: UDCA ‐ Dose: 600 mg/day; ‐ Route: orally; ‐ Timing: not described; ‐ Duration: 18 months. Alpha IFN ‐ six million units intramuscular injection daily for two weeks, and then three times a week for 22 weeks. IFN group: Alpha IFN ‐ six million units intramuscular injection daily for two weeks, and then three times a week for 22 weeks.
Outcomes	‐ Normalisation of serum ALT at the end of treatment and follow‐up. ‐ Absence of serum HCV RNA negativity at the end of treatment and follow‐up.
Notes	Follow‐up time: 12 months. We sent letter for more information on trial methodological quality and missing data on April 17, 2001, but no response was received.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear