Correlates of Hepatitis B Virus Infection among Antenatal Clinic Attendees of Volta Regional Hospital, Ho, Volta Region, Ghana

Ghana is among the high endemic countries in Africa, with HBV prevalence ranging from 4.8% to 12.3% in the general population, 10.8% to 12.7% in blood donors and about 10.6% in antenatal clinic (ANC) attendees. The main objectives of this study were to test how socioeconomic factors, risky behaviors, knowledge and awareness of HBV infection correlate with actual HBV status among antenatal clinic attendees and to determine the predictors of HBV testing among ANC attendees.

The study is a cross sectional study. Structured questionnaires were used to determine the knowledge level of the study population. On the knowledge of HBV infection, questions including the transmission of the infection, risk factors, management, prevention and immunization against the infection were asked. Information on the status; presence or absence of hepatitis B surface antigen, and socio-demographic information (Age, Marital status, Residence, Number of children, Religion, Level of education, Occupation), Parity (number of children), history of blood transfusion and sexual history (number of life-time sexual partners) were collected using the structured questionnaire and/or from the antenatal record books of the study subjects. The data was obtained through face-to-face interview and interpretation of the question was either carried in English, Ewe and Twi; and in the participants’ dialect.

The population includes pregnant women reporting for routine antenatal check-up between 1st February, 2017 and 27th April, 2017. A systematic random sampling was adopted to give all potential respondents an equal chance of being selected for the study. With an average daily attendance at the booking clinic of about 50, an average of 5 questionnaires was administered/day giving a sampling interval of 10. Using the booking records books at the antenatal clinic the first respondent was selected from the first 10 attendants randomly by balloting. The next respondent was therefore the 10th attendant after the first attendant sampled and then it followed. If an attendant declined to participate, the third attendant after her was selected.

Predetermined criteria were the bases for this sampling method. Sample size was determined as expressed in
Equation (1): n= ((z^2 ) (p) ( 1-p))/E^2.
Where, n = the estimated sample size; E is the desired margin of error (0.05); z is the statistic for the level of confidence (95%) = 1.96; p is the (10.6%) prevalence of HBV infection among pregnant women in the Eastern Region of Ghana in a previous study in 2012. From Equation (1), the minimum sample size is 137. Adding 20% gives a sample size of 164 which catered for unforeseen circumstances such as uncompleted questionnaires. The final study size was 500 participants.
Keywords: Binomial Logistic Regression, Hepatitis B Virus Infection, Antenatal Clinic Attendees

加纳是非洲乙型肝炎病毒（Hepatitis B Virus, HBV）高流行国家之一，一般人群中HBV流行率为4.8%~12.3%，献血人群为10.8%~12.7%，产前检查门诊（Antenatal Clinic, ANC）就诊者约为10.6%。

本研究的主要目的为探究产前检查门诊就诊孕妇中，社会经济因素、危险行为、HBV感染认知情况与实际HBV感染状态之间的关联，并明确ANC就诊者接受HBV检测的预测因素。

本研究为横断面研究。研究采用结构化问卷评估研究人群的认知水平，针对HBV感染认知的问卷内容涵盖该感染的传播途径、危险因素、诊疗管理、预防措施及疫苗接种等问题。研究通过结构化问卷及受试者的产前诊疗记录，收集以下信息：HBV感染状态（即乙型肝炎表面抗原（hepatitis B surface antigen, HBsAg）阳性与否）、社会人口学信息（年龄、婚姻状况、居住地、子女数、宗教信仰、受教育水平、职业）、产次（即生育子女数）、输血史及性行为史（终身性伴侣数量）。数据通过面对面访谈获取，问卷解读可采用英语、埃维语、特维语，或使用参与者的本土方言进行。

研究人群为2017年2月1日至2017年4月27日期间前往该门诊接受常规产前检查的孕妇。本研究采用系统随机抽样法，确保所有潜在受访者均有均等的入选机会。该产前建档门诊日均接诊约50人次，因此日均发放5份问卷，抽样间隔设为10。研究人员通过产前建档门诊的就诊记录，采用抽签法从首批10名就诊者中随机选取第一名受访者；后续受访者则为前一名抽中者之后的第10名就诊者，依此类推。若某就诊者拒绝参与研究，则选取其之后的第三名就诊者作为替代。该抽样方法基于预先设定的标准实施。

样本量按照公式（1）计算得出：n = (z²p(1-p))/E²。其中，n为估算样本量；E为期望边际误差（0.05）；z为95%置信水平对应的统计量（1.96）；p为2012年加纳东部地区一项既往研究中孕妇HBV感染流行率（10.6%）。根据公式（1）计算得出最小样本量为137，追加20%的余量至164，以应对问卷未完成等意外情况。本研究最终纳入500名受试者。

关键词：二项Logistic回归、乙型肝炎病毒感染、产前检查门诊就诊者