Immune tolerance is a phase most patients leave within five years

Design

international multicentre natural-history cohort study with competing-risk analysis, median follow-up 13 years

Population

951 mono-infected patients with strictly defined immune-tolerant chronic hepatitis B; median age 33, 40% male, median ALT 25.5 U/L, median HBV DNA 8.4 log10 IU/mL

Primary outcome

transition to immune active disease (ALT 50 U/L or above); significant fibrosis; hepatocellular carcinoma

Effect

transition in 51% by 5 years, 67% by 10, 72% by 15; ALT 20-30 U/L sHR 1.744 and above 30 U/L sHR 3.130 (both p<0.001); significant fibrosis 6.3% and HCC 1.1% at 15 years

The RADICAL consortium assembled 951 patients with chronic hepatitis B meeting a deliberately strict definition of the immune-tolerant phase: persistently HBeAg-positive, ALT at or below 40 U/L, HBV DNA above 7 log10 IU/mL and F0-1 fibrosis throughout the first year. Median age was 33, 40% were male, and median follow-up was 13 years. Median baseline ALT was 25.5 U/L and HBV DNA 8.4 log10 IU/mL.

The probability of transitioning to immune active disease, defined as ALT reaching 50 U/L, was 51% by five years, 67% by ten and 72% by fifteen. Baseline ALT within the normal range predicted it: against ALT below 20 U/L, a value of 20-30 U/L carried a subdistribution hazard ratio of 1.744 and above 30 U/L a ratio of 3.130 (both p<0.001). Meanwhile the feared outcomes stayed rare — significant fibrosis in 6.3% and hepatocellular carcinoma in 1.1% at fifteen years.

Both halves matter. The low fibrosis and cancer rates support not treating these patients immediately, which is what guidelines say. But a 51% five-year transition rate means the annual review interval most services use is not surveillance, it is sampling. And the ALT value that should trigger closer follow-up is one that currently reads as normal on the report — a 28 U/L in a young HBeAg-positive patient is a reason to come back in three months, not twelve.

• Read ALT as a continuous variable in this group; 20-30 U/L is not the same as under 20
• Shorten the review interval for a high-normal ALT rather than waiting for a value flagged as abnormal
• Reassure about fibrosis and cancer risk — both remained low over fifteen years
• Reconfirm the phase before accepting it: the strict definition here required persistence over a year
• Chronic hepatitis B in India is largely diagnosed in this age group and lost to follow-up in it; the review interval is the intervention

Why it matters

It turns the annual review of an immune-tolerant patient from adequate into inadequate, and names the marker that says who needs more.

Don't overread it

This is natural history, not a treatment trial — it does not show that pre-emptive antiviral therapy in this group improves anything.

The statistics, in plain English

A subdistribution hazard ratio accounts for competing events — here, that a patient might lose HBeAg rather than become immune active — so it estimates the risk of the specific transition rather than of any change. The 51% five-year figure is a cumulative probability across a cohort followed for a median of 13 years, so it is well supported rather than extrapolated.

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