Vaccination against hepatitis B virus in hemodialysis patients: trends in dialysis centers of Northern Pakistan

Introduction

Chronic kidney disease (CKD) is a global health problem; estimated global prevalence is 11–13% with majority of the patients having stage 3 disease¹. It is an immunosuppressive state, so CKD patients are at increased risk of developing many infections; some of these infections are vaccine preventable². Hepatitis B virus (HBV) infection is among one of those infections. Like other high risk groups including IV drug abusers, homosexual men, having history of piercing and blood transfusions, it is more prevalent in CKD patients as compared to the general population^3–5. High risk of HBV among hemodialysis patients is due to increased exposure to blood products, frequent cannulation and shared hemodialysis equipment⁶.

HBV infection in CKD patients varies globally and correlates with the prevalence in the general population. Decreasing trends have been seen in developed countries; in the US it decreased from 7.8% in 1976 to 1% in 2002³. The exact prevalence among CKD and dialysis patients in the developing world, including Pakistan, is not well known. There are scattered reports, mostly single-centre surveys; according to these surveys hepatitis B surface antigen (HBsAg) carrier rate ranges between 2% to 20%⁶. In Pakistan, the prevalence rate is about 4% in the general population⁷, indicating that it will be more than 4% in CKD patients.

Prevention is the best option in the general population, as well as in high risk groups to reduce the prevalence of hepatitis B infection because treatment is lengthy, costly and not 100% effective. As HBV can be transmitted easily from the medical equipment used during dialysis, as it remains viable and stable in the environment for weeks at room temperature⁸, vaccination against HBV is most effective way to prevent it in CKD patients on hemodialysis. Complete vaccination was found to be protective in ≥90% in the general population, even 30 years after vaccination⁹. Although response is not good in chronic renal failure patients, up to 40% were found to be non-responders in some studies^3,10. Still routine vaccinations of patients and healthcare workers has dramatically reduced the prevalence of HBV infection in hemodialysis patients¹¹. It was found 70% lower among vaccinated patients as compared to non-vaccinated hemodialysis patients¹².

Guidelines from nephrology societies and Centers for Disease Control and Prevention suggest that all patients with CKD should be vaccinated against HBV². Special formulation of recombinant vaccine is advised, either higher dosage or increased number of doses (4 doses) should be administered for good results². Although guidelines strongly recommend vaccination of CKD patients against vaccine preventable diseases, it has been shown that they are not in fact routinely vaccinated against HBV. A study published in the UK showed that only 46% dialysis units were routinely immunizing patients according to the Renal Association’s recommendations¹³, while only 20% of patients were found to be vaccinated in a study conducted in Pakistan¹⁴.

Vaccination against HBV decreases the overall mortality in CKD patients, but, to the best of our knowledge, no recent data is available regarding the status of vaccination against HBV in CKD patients internationally. In developing countries, including Pakistan where hepatitis B is still a common problem, there is limited data available on this topic. The aim of this study was to observe the immunization status of CKD patients on regular hemodialysis against hepatitis B in Pakistan. The data can help in future for necessary measures to improve the vaccination against hepatitis B in CKD patients in order to reduce the HBV related morbidity and mortality in hemodialysis patients.

Methods

Results

A total of 200 patients were asked to take part in the study, but only 149 responded. A total of 63.1% (n=94) were male and 36.9% (n=55) were female. Mean age was 50.5±16.7 years, with minimum age of 7 years and maximum 83 years. Mean duration of CKD was 38.9±47.2 months. Out of these 149 patients, 24.2% (n=36) were uneducated, 33.6% (n=50) had 1–10 years school education (up to secondary level), whereas 38.2% (n=57) had 10–14 years education (secondary level to graduation) and 4% (n=6) had more than 14 years education (post-graduation). About 35.6% (n=53) patients were from low socioeconomic class, 53.6% (n=80) from middle, and 10.8% (n=16) from higher class. Only 45.6% (n=68) patients were vaccinated and 54.4% (n=81) were not vaccinated against HBV (Table 1).

A significant association was found between vaccination status and education of the patient; better educated patients were more likely to be vaccinated (Table 2). A significant association was also found between vaccination and socioeconomic status of the patients; patients from middle and upper classes were more likely to be vaccinated as compared to lower class. (Table 3). Vaccination status of the patients was not significantly associated with age (p= 0.540), gender (p= 0.517), and duration of CKD (p= 0.719).

Discussion

In our study, we found that 45.6% patients of CKD on regular dialysis were found to be vaccinated against HBV. We concluded that education and socioeconomic status are two important factors associated with status of vaccination, and vaccination status was not associated with age, gender, and duration of CKD.

Results showed that 63% patients were male, and the mean age of patients was 50 years. This suggests that more male patients are on hemodialysis and CKD is also more common in the older age group. This is the same as the United States Renal Data System 2011 Annual Data Report that showed that the initiation of dialysis was much higher in males as compared to females¹⁸. However, a meta-analysis reported that in some studies CKD was more common in females, while in other studies it was more common in males¹. Many studies showed that CKD is more common in an older age group¹, comparable with our findings. For example, in a study conducted in India¹⁹, the mean age was 51 years in CKD patients, while in a Chinese study it was found to 63.6 years²⁰, almost the same as in our study. We did not find any association between status of vaccination and age or gender; this was also concluded by Amjad et al. in a study conducted in Pakistan¹⁴.

Nephrology societies and Centre for Disease Control and Prevention recommends that all CKD patients should be vaccinated against HBV². These guidelines are not followed even in the developed world; 73.1% patients of CKD were found vaccinated in US²¹, and only 31% patients were vaccinated in a study conducted in Belgium²². Our results are also not encouraging, only 45.6% were found vaccinated, while in another study from Pakistan only 20% patients were vaccinated, consistent with our results¹⁴. A study conducted in Brazil showed better vaccination rates compared to our results, almost 60% patients were completely vaccinated, and another 15% were partially vaccinated²². The low vaccination rate in Pakistan indicates that dialysis centers and nephrologists are not following the guidelines of nephrology societies regarding vaccination against hepatitis B.

Our study reported that vaccination status in dialysis patients was significantly associated with socioeconomic class and education of the patients. A vaccinated status was found to be higher in CKD patients with better socioeconomic status in another study conducted in Pakistan¹⁴. Another study conducted by Ertekin et al. showed that better socioeconomic status was associated with higher rates of vaccination in the general population²³. These results are same as we found in our study. Low vaccination rates among lower socioeconomic groups may be due to non-affordability. As far as education is concerned, no association was found between vaccination against HBV of CKD patients and education in a study conducted by Amjad et al.¹⁴, which differs from our results. Studies from the general population and healthcare workers showed that education was significantly associated with vaccination status against HBV, comparable to our results^24–26. Individuals who have more education may be better aware of the preventive role of vaccination, which may be the cause of better vaccination status in higher educated people. It shows that awareness about vaccination and its preventive role is important. In order to improve the status of vaccination we suggest that CKD patients should be educated about the importance of vaccination in preventing the HBV infection by implementing the special educational programs for these patients. Vaccination rates can also be increased by free vaccination programs for CKD and hemodialysis patients.

Our study is subject to some limitations. First, we only included those patients who were on regular dialysis. Second, only two dialysis centers were included in the study and few factors were studied related to vaccination status. We recommend future studies to include all patients of CKD from many centers.

Conclusion

Currently dialysis centers are not following guidelines regarding vaccination against HBV in hemodialysis patients. Vaccination status of patients on hemodialysis is not satisfactory in dialysis centers we sampled in Northern Pakistan. We found that vaccination status is significantly associated with education and socioeconomic status of the patients.