Progression from acute to chronic hepatitis B is more common in older adults

The rate of progression of acute Hepatitis B (HBV) to chronic disease is quoted as <10%. The purpose of this study was to determine the rate of progression from acute to chronic HBV in Northern Ireland (NI), assessing the influence of age, gender and biochemical parameters.

All "acute" HBV cases diagnosed in NI between 2011 and 2015 were reviewed. Inclusion criteria: 1). positive HBsAg and positive HBV core IgM; 2). in the absence of positive HBV core IgM, positive HBsAg with a recent negative HBsAg. Patient age, HBsAg, HBV core IgM, peak bilirubin and peak ALT were recorded, along with date and result of repeat HbsAg testing. Mann-Whitney U test was used to compare mean age, peak ALT and bilirubin between clearing and non-clearing groups. Fisher's exact test was used to compare progression to chronicity according to gender and age less than or greater than 50yrs.

Of 80 identified cases, 4 incorrectly categorised cases were excluded. Of the remaining 76, (15 female (mean age 37.27yr), 61 male (mean age 47.39yr)) follow-up data was available for 71 patients (15 female (mean age 37.27yr), 56 male (48.59yr)). All female patients cleared HBV. 42 of 61 males cleared HBV (p=0.0313).Overall the chronicity rate was 18.42% The mean age of those clearing the virus was 43.88 years, versus 55.64 years for those going on to develop chronic HBV (Mann-Whitney U test, z= -2.68, p=0.0037). Clearance rate was 83.72% in patients aged <50yrs and 63.64% in patients 50yrs (p=0.0068).Mean peak ALT (U/L) and peak bilirubin (µmol/L) for the clearing group were 2130 and 174 respectively compared to 656 and 100 for the non-clearing group (z= -3.51, p=0.0002, z= -2.35, p=0.009).

Our results suggest a higher than expected rate of progression from acute to chronic HBV with a significantly higher risk for those over 50yrs. This suggests a need to revise information provided to older patients with acute HBV regarding the likelihood of progression.