P104 Risk factors associated with the negativisation of anti-HBs antibodies in inflammatory bowel disease patients
A. C. Marín*1, M. Chaparro1, M. Ramas1, R. R. Ribot1, P. M. Linares1, J. R. Villagrasa2, D. Bernardo1, J. P. Gisbert1
1Hospital Universitario de La Princesa, IIS-IP and CIBERehd, Gastroenterology Unit, Madrid, Spain, 2Hospital Universitario de La Princesa and IIS-IP , Preventive medicine unit, Madrid, Spain
The vaccine against hepatitis B (HBV) is less effective in patients with inflammatory bowel disease (IBD) than in the healthy population. Further, it has been suggested that anti-HBs antibodies negativisation rate following a successful vaccination is higher in such patients compared with healthy controls. The aim of this study was therefore to evaluate the anti-HBs negativisation rate in a cohort of IBD patients and to investigate the risk factors associated to such lose.
Inclusion criteria: IBD patients not infected by HBV who were successfully vaccinated against HBV (determined as titles of anti-HBs > 10 IU/L following vaccination) between 2008 and 2010. Follow-up period: from the date of vaccination until 2015. Procedures: Anti-HBs titles were retrospectively collected from the clinical history of the patients. Events were considered as negativisation if antibodies titles were <10 IU/L at any serology. Statistical analysis: logistic regression was applied, being the dependent variable the negativisation of anti-HBs, and possible risk factors were investigated as covariates (type of IBD, gender, smoking habit, age of the patients at vaccination, anti-HBs titles after vaccination, and treatment with immunosuppressants or biologics).
Included were 95 patients (65% Crohn’s disease, 52% female, and 26% smokers). During vaccination, 24% of patients were treated with immunosuppressants and 15% with biologics. Median follow-up was 18 months (range: 1–81 months) and the prevalence of negativisation was 24%. The proportion of patients who lost antibody titles was significantly higher amongst those who had anti-HBs < 100 IU/L (measured at 1–6 months after vaccination) compared with those with anti-HBs > 100 IU/L (78% vs 20%; p < 0.001). The predictive model of developed negativisation (shown in the table) corroborated that titles of anti-HBs > 100 IU/L were highly associated with a reduced probability of negativisation, whereas treatment with biologics during vaccination markedly increased the risk of losing anti-HBs.
Negativisation of anti-HBs antibodies in IBD patients is much more common in patients with low post-vaccine antibody titles and in those treated with biologics during vaccination.