FACTORS INFLUENCING THE EFFICACY OF HEPATITIS B VACCINATION IN PATIENTS UNDERGOING HEMODIALYSIS

Prevention of infection by hepatitis B virus in patients undergoing hemodialysis is very important but has its own problems such as reduction of hepatitis B vaccination efficacy and the falling of HbsAb to unprotective levels after unknown time. These factors bring up a need for assessing the antibody levels at specified times (e.g. every 6 months) and revaccinating the patients when it seems necessary. The present study was conducted to determine the factors that influence the efficacy of hepatitis B vaccination in patients undergoing hemodialysis. This case-control study was carried out on 121 patients undergoing hemodialysis in the hemodialysis ward of Shahid Hasheminejad Hospital in Tehran. 64 patients(with antibody levels under 10mlU/ml) were in case and 52 ones (with antibody levels equal or more than 10mlU/ml) were in the control group. The checklist consisted of demographic and laboratory information, duration of hemodialysis, history of having diabetes and history of smoking which were all extracted from the patients’ hospital records and/or asked from them. Analysis of the data was done via SPSS 10 and EPI Info 6 software using indices of frequency, mean, standard deviation and standard error. Different statistical tests such as Chi2, Levene, Kolmogorov-Smirnov, t, and Pearson and Spearman coefficients were also employed. Multiple linear regression was used for assessing the predicting factors. Of 121 patients, 56 were female and 65 were male. Rh-positive blood group had more frequency in cases than in controls (P=0.010, odds ratio=2.63) and the number of the smokers was significantly more in the control group than in the case (P=0.031, odds ratio=0.27). Moreover, increases in weight (P=0.015, r=-0.225) and age (P=0.006, r=-0.253) decreased the HbsAb levels significantly. The patients’ age and Rh blood group were the identifiers of antibody levels in the regression model. This study has found out that increasing age, malnutrition and Rh-positive blood group are factors in decreasing the efficacy of hepatitis B vaccination in patients undergoing hemodialysis and it has also marked the need for paying further attention to the patients having these risk factors.