Association between socio-economic factors and HIV self-testing knowledge amongst South African women

Background Self-testing for HIV is an effective and alternative method of increasing HIV testing rates and a strategy for reaching populations that are underserved by HIV testing services. Nonetheless, many resource-constrained settings are yet to adopt HIV self-testing (HIVST) into their national HIV programmes. Objectives This study aimed to examine the association between socio-economic factors and HIVST knowledge amongst South African women. Method We used nationally representative data from the 2016 South African Demographic and Health Survey. A sample of 8182 women of reproductive age was analysed. The outcome variable was HIVST knowledge. This was measured dichotomously; know versus do not know about HIVST. The multivariable logistic model was used to examine the measures of association, with the level of significance set at P < 0.05. Results The prevalence rate of HIVST knowledge was found to be approximately 24.5% (95% confidence interval [CI]: 22.9–26.1) amongst South African women. Women with tertiary education were 3.93 times more likely to have HIVST knowledge, when compared with those with no formal education (odds ratio [OR]: 3.93; 95% CI: 1.37–11.26). Rural residents had a 33% reduction in HIVST knowledge when compared with those residing in urban areas (OR: 0.67; 95% CI: 0.51–0.89). The odds of interaction between the richer and richest women who have good knowledge of HIV infection were 1.88 and 2.24 times more likely to have HIVST knowledge, respectively, when compared with those from the poorest wealth household who have good knowledge of HIV infection. Conclusion Based on the low level of HIVST knowledge, the findings emphasise the importance of developing effective HIVST educational campaigns. Moreover, programmes should be designed to address the unique needs of the socio-economically disadvantaged women.

This varies by age group, sex, level of education, marital status, wealth status, place of residence and geographical region, exposure to media and HIV stigma. 4,5,6,7 Women, older individuals, those with lower educational achievement and low socio-economic status are groups who are less aware of HIVST. 4,5,6,7 The knowledge of HIVST is reportedly low amongst men and women in South Africa, with men being more aware than women. 4,9 A study that looked at HIV testing and selftesting coverage amongst men and women in South Africa indicated that awareness of self-testing was low (2.02%), and that a very few (2.90%) respondents had ever self-tested for HIV. 4 The study also showed that highly educated individuals, those living in wealthy households, urban residence and those often exposed to media had a higher awareness of HIVST. 4 Although the main source of HIVST awareness amongst women in South Africa was media channels, 9 the lack of HIVST awareness or knowledge amongst this group may have resulted from gaps in HIVST education within primary health care facilities and deficiencies in clinical research. 9 Additional factors include the lack of HIV counselling, fear of a positive HIV result and failure to link to care. 9 The knowledge of HIVST is especially important amongst women in communities with high HIV burden such as South Africa, where safe sex practices are not followed and sexual concurrency is frequent. 10 Communal knowledge of HIVST is essential for the success of prevention programmes and for the realisation of the United Nations Programme on HIV/AIDS' (UNAIDS) 95-95-95% 2030 goals. 11 Several studies have shown that socio-economic factors drive the transmission of HIV amongst adolescent girls and young women. 10,12 Despite the high incidence of HIV in South Africa, particularly amongst women, and the socio-economic inequalities experienced by women, there is little understanding of the actual socio-economic contributors influencing their HIVST knowledge. The objective of this study was to examine the association between socioe-conomic factors and HIVST knowledge amongst South African women.

Study design
This research study was based on a cross-sectional household survey, the South African Demographic and Health Survey (SADHS) of 2016. 13 This used a stratified two-stage sample design, with sampling probability proportional to the size of primary sampling units (PSUs) in the first stage and systematic sampling of dwelling units (DUs) in the second stage. The sampling frame used in the survey is the Statistics South Africa Master Sample Frame (MSF), which was created using Census 2011 enumeration areas (EAs HIV-related knowledge was computed as the sum of the correct answers to vital questions. For questions assessing HIV knowledge, answers were recoded as follows: correct answer = 1, incorrect answer = 0 and do not know = 0. Twelve questions were included in the HIV infection knowledge total score, giving a highest possible total score of 12. We computed the mean value of the scores. A respondent with a score below the mean value was classified to have poor knowledge. A respondent with the score at or above the mean value was classified as having 'good knowledge'. Table 1 lists questions on the HIV-related knowledge. The inclusion of the factors was based on previous studies. 14,15,16

Socio-economic variables
Women's educational level, household wealth, and residential and employment status were selected as the socio-economic factors in this study. Previous studies 12,17,18,19 also used these factors whilst investigating for socioeconomic factors. Women's education was categorised as no formal education, primary, secondary and higher. The place of residence was categorised as urban or rural. Employment status: yes, if currently employed versus no, if unemployed. The procedure to determine household wealth is complex but is elaborated in detail in a previous study by authors of this study. 12

Statistical analysis
To adjust for the sampling design, the survey module ('svy') command was used. Multicollinearity, which is known to be a major source of concern in regression models, was determined using a variance inflation factor of 10. 20 Nevertheless, no variable was removed from the model because they were determined to be unrelated. In univariate and bivariate analyses, the percentage and chi-square tests were used, respectively.
It is assumed that respondents who are living with HIV will have greater knowledge of HIVST. We examined the interaction between HIV knowledge and socio-economic factors to confirm or reject this assumption.
The predictive marginal effect model included all significant variables from the bivariate analysis (with corresponding 95% CI). The predictive marginal effect model is presented thus as follows: where Set [E = e] reflects putting all observations to a single exposure level e and Z = z refers to a given set of observed values for the covariate vector Z. Furthermore, P eẑ is the predicted probabilities of HIVST knowledge for any E = e and Z = z. The marginal effects indicate a weighted average over the distribution of the covariates and are equal to estimates obtained by standardising the entire population.
As a post logit test, exposure E is set to the level e for all women in the data set, and the logit coefficients are used to compute predicted probabilities for every woman at their observed covariate pattern and newly exposure value. Because predicted probabilities are computed under the same distribution of Z, there is no covariate of the corresponding effect measure estimates. 21

Ethical considerations
This study is a secondary analysis of data derived from the 2016 South African Demographic and Health Survey (SADHS) and anonymised of any identifier information for this investigation. The survey protocol was reviewed and approved by the South African Medical Research Council (SAMRC) Ethics Committee and the Inner City Fund (ICF) Institutional Review Board. MEASURE DHS/ICF International granted the authors permission to use the data. The DHS programme adheres to industry norms for preserving the privacy of respondents. ICF International assures that the survey complies with the Human Subjects Protection Act of the United States Department of Health and Human Services.
The distribution of HIVST knowledge across women in South Africa is discussed, as presented in  Table 2.

Yes No
Ever heard of AIDS In  Table 3).    As shown in Figure 1, the marginal effects plot of HIVST knowledge by educational attainment and HIV infection knowledge is presented. The marginal interaction effects of HIVST knowledge were greater for women who had tertiary education than those with no formal education who had good HIV infection knowledge.
As presented in Figure 2, based on the marginal effects plot of HIVST knowledge by household wealth and HIV infection knowledge, the marginal interaction effects of HIVST knowledge were higher amongst women having good knowledge of HIV infection (brown line), particularly in the richer and richest households.
As shown in Figure 3, according to the marginal effects plot of HIVST knowledge by residential status and HIV infection knowledge, the marginal interaction effects of HIVST knowledge were found to be higher amongst women in the urban residence.

Discussion
We examined the knowledge of HIVST amongst South African women using a nationally representative large data set. The prevalence rate of HIVST knowledge in this group was approximately 24.5%, which was higher than that reported amongst the Malawian (11.4%) and Zimbabwean (14.5%) population, respectively. 23 More effort is needed to implement evidence-based HIVST interventions to reach   women, to both improve their knowledge and practice, such as through healthcare facilities and antenatal care in high HIV-burden settings, or through networks of other high-risk sexual and social contacts, including those with HIV. 24 Fear of discovering one's HIV status may be behind the lack of knowledge or awareness of self-testing. 25,26,27 Social marketing improves the knowledge or uptake of HIVST 28 as observed in studies involving men who have sex with men (MSM). 29,30,31 In this study, exposure to mass media was positively associated with HIVST knowledge. Social marketing of key messages and strategies that promote HIVST on mass media platforms are likely to be impactful in Africa. 25,32,33 In this study educated, compared with uneducated, women, had a greater knowledge of HIVST. Furthermore, the knowledge of HIVST amongst women was found to increase with educational advance from primary to tertiary levels, the outcome of which has been shown in other studies. 26,34,35 Education assists with knowing one's HIV status: lower levels of education correlate with less knowledge of HIV infection and a lower uptake of HIV services. 12,35,36,37 Wealth is correlated with greater knowledge of HIVST. Better HIVST knowledge was observed amongst employed women than unemployed. Although these findings have been reported inconsistently, 38,39 employment brings financial independence and independence with regard to health decisions. When women are denied such freedoms, their health, including HIV self-knowledge, may be compromised. In order to mitigate this challenge, community sensitisation, social mobilisation and women's empowerment should be considered a key intervention in women's HIVST. Wealth is correlated with improved knowledge of HIVST by facilitating access to health information, facilities and choices, and providing access to people in the know. 40 Where you live matters. Rural people are more likely to be underserved with healthcare services and to experience barriers in access to health information. 41,42 Knowledge of HIV in this study varied by place of residence. Lack of access to appropriate health information could be improved by better media coverage of health issues. Nevertheless, media reporting on health issues is of varying quality, particularly messages about HIV testing, counselling and treatments. 43,44 During the coronavirus disease 2019 (COVID-19) pandemic, the media has played a very important role in supporting all citizens to make informed choices. Why can this not be performed with regard to HIVST too?
There is an increased HIVST knowledge interaction effect by high socio-economic status and good HIV infection knowledge. Increase in wealth was observed to have a positive marginal interaction effect with increased HIV infection knowledge amongst the South African women. As

Pr(know HIV test kits)
.2

Currently working
Yes the wealth status of the women increased, their knowledge of HIVST also increased. This implies that having good knowledge of HIV infection and being from a wealthy household are associated with having good knowledge of HIVST amongst the study population. Hence, it is necessary to promote women's health, particularly their sexual and reproductive health, and ways in which communities can engage in advancing the rights of women to make informed health decisions. The fact that this study's results revealed that poor and illiterate women had lower levels of HIVST knowledge validates the existing global perspectives on the association between low socio-economic status and poor health outcomes, such as HIV infection. 45,46 As a result of their low socio-economic status, the poor or under privileged and those with low educational attainment could face the dual problem of high vulnerability and a lack of opportunities to make better health choices (such as access to information on prevention, testing and counselling for HIV infection).
Besides the socio-economic status, other contextual factors associated with low knowledge of HIVST should be identified and addressed simultaneously.
It is crucial to undertake interventions that incorporate specific designs targeted at women of low socio-economic status. Women's empowerment, decision-making authority, girl-child education and women's autonomy, for example, could favourably influence the utilisation of healthcare services, including HIV prevention, in South Africa. The government, non-governmental organisations and other stakeholders in the healthcare system should create and promote key interventions, such as free HIV screening or testing, as well as counselling and treatment for HIV-positive women. 47 This will encourage more women, particularly those from poor backgrounds, to participate in HIV prevention, control and treatment programmes. Furthermore, the government and support groups will be required to enrol low-income, HIV-positive women in a specific financial assistance programme. 48 Such a strategy might be aimed at providing economic assistance to underprivileged women, as well as lowering their HIV burden. Furthermore, special messaging aimed at increasing awareness and education of HIV amongst low-income women, the uneducated, or those living in difficult-to-reach regions might be beneficial in the battle against HIV. Women aged 20-39 years, those from Free State, North West and Gauteng were more likely to have good knowledge of HIVST when compared with those aged 15-19 years and those from Western Cape. However, women who were long-term residents were less likely to have good knowledge of HIVST when compared with those who lived in the household less than 5 years. This is consistent with previous findings that demographic characteristics were associated with HIVST knowledge. 4

Strengths and limitations
The strengths and limitations of this study are similar to those reported in a previous study, which used DHS data. 12 For example, this study used nationally representative data, which is suitable for making plausible comparisons. However, data from a cross-sectional study were analysed, and therefore only association and not causality can be determined. Another limitation is the assumption that respondents who are living with HIV will have a greater knowledge of HIVST.

Conclusion
According to the findings of this study, the knowledge of HIVST is relatively low amongst South African women. In addition, socio-economic factors were associated with HIVST knowledge. This study has a wide range of implications.