Spanish multicentre PIBHE study: Prevalence and immunization of chronic hepatitis B in haemodialysis patients in Spain.

Introduction: The PIBHE study, promoted by the Spanish Liver and Kidney Association and the Dialysis Virus Group of the Spanish Society of Nephrology, is the first study to determine the status of haemodialysis patients with chronic HBV infection and the immunisation against the vaccine.

Method: The study has a national multicentre, observational, cross-sectional design and was carried out between January 2013 and 2014. A data collection folder was sent to all the nephrology departments and outpatient haemodialysis units in Spain, to be completed based on patient medical files after informed consent. The data were recorded in a central database.

Results: A total of 215 centres participated (15,645 patients), with an HBV prevalence of 1.03%. HCV or HIV was present in 7.2% of the HBV(+) patients. Viral load was below 2,000 IU/ml in 80%. GOT and GPT levels were 19.1±10.1 and 15.9±9.6 IU/ml, respectively. Liver biopsy was performed in 7.1%. Antiviral treatment was prescribed in 30% and suspended in 12.5%: entecavir (13.3%), lamivudine (10%), adefovir and tenofovir (6.7%), and interferon (3.3%). A total of 34.5% were candidates for renal transplantation and 6.9% had not been evaluated; 64.3% were followed up by a gastroenterologist; 27.2% of HBV(-) patients without immunisation had not been vaccinated. Fourteen different immunisation schedules had been used, with an immunisation rate of 58.8%. Mean anti-HBs stood at 165.7±297.8mIU/ml. A total of 72.7% of patients had received a vaccination course; 26.4%, 2 cycles; 1.0%, 3 cycles; and 11.6%, a booster dose. A total of 28.3% had a poor response (anti-HBs 10-99mIU/ml); 22.4%, an optimal response (anti-HBs 100-999mIU/ml); and 7.9%, an excellent response (anti-HBs ≥ 1,000mIU/ml). Age was significantly associated with response to vaccination; the mean age of nonresponders was significantly higher than patients who had a response of any kind (P<.05). The highest probability of an immune response was achieved with 4 doses of 40 mcg of adjuvanted vaccine (OR: 7.3; 95% CI 3.4 to 15.7), for the same age and number of cycles and boosters. Age, adjuvanted vaccine, dose and vaccination schedule influenced the immune response and the anti-HBs titres reached (P<.05).

Conclusion: The prevalence of chronic HBV infection in haemodialysis in Spain is low and so are the rates of immunisation against the virus. The vaccination schedules used are very diverse and have been observed to correlate with the immune response. It would therefore be necessary to establish a protocol for the most effective vaccination schedule to increase immunisation in these patients.