Doctoral Degrees (Epidemiology and Biostatistics)

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Browsing Doctoral Degrees (Epidemiology and Biostatistics) by browse.metadata.advisor "Nyasulu, Peter"

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    HIV continuum of care outcomes among female sex workers in Kampala Uganda
    (Stellenbosch : Stellenbosch University, 2022-12) Atuhaire, Lydia; Nyasulu, Peter; Shumba, Constance; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Global Health. Epidemiology and Biostatistics.
    ENGLISH SUMMARY: Background: Female sex workers (FSWs) account for 11% of all HIV infections globally and are twenty-six times at a greater risk of acquiring HIV than their female counterparts in the general population. In Uganda, HIV prevalence among FSWs is estimated at 31% - 37%, six times higher than the HIV prevalence of 5.4% in the general population. FSWs, not only are confronted by heightened risk to HIV infection, but they are also more vulnerable to social and economic inequalities that hinder access to HIV services throughout the HIV care continuum. Moreover, the few HIV positive FSWs who eventually access HIV care, experience unique barriers that hinder their continuity on life-long Antiretroviral therapy (ART) and thus drop out of care along the various stages of HIV continuum of care. Consequently, FSWs continue to widen the gap to attaining the global HIV treatment targets of 95-95-95 by 2025 and ending the AIDS epidemic by 2030. Notably, there has been an increased focuson improving HIV care continuum. However, data are sparse regarding the service uptake across the HIV care cascade for FSWs. Absence of recent data for FSWs impedes monitoring of HIV service provision and identifying missed opportunities important in guiding program strategies, optimal for improved and equal access to HIV services among FSWs. The aim of this research project was to understand service delivery approaches along the HIV continuum of care for FSWs in a routine care setting in Kampala, Uganda. Methods: The research project used multiple approaches to respond to the objectives as described as follows: In objective one, we conducted a systematic review on the implementation of community interventions for any of the HIV care cascade stage. We conducted a systematic search of randomized controlled trials, cohort and cross-sectional studies done in sub-Saharan African countries and published from 2004 to 2020. The study outcomes were HIV testing and diagnosis, linkage to care, receipt of ART and achievement of viral suppression. The data were analysed using random effects meta-analysis, where possible and for the rest of the studies, data were synthesized using summary statistics. For objective two, we conducted a cross-sectional survey and used simple random sampling method to select 200 participants from 12 sex work hotspots in Kampala. Participants were allocated proportionally in each hotspot. Frequencies were used to describe categorical characteristics of FSWs, and a multivariable logistic regression model was used to determine the factors associated with adherence to the HIV testing guidelines. In the third objective, we performed a retrospective cross-sectional study of routine patient management data for FSWs diagnosed with HIV and enrolled in care from January 2018 to December 2020 at the government primary health care facilities in Kampala. Two outcome variables were assessed and these which included i) Lost-to-follow-up from HIV care; and ii) Virological non-suppression. We used cluster sampling methods to select initial clusters and purposively selected a cluster of six health facilities and data was collected from 275 medical records. Both univariable and multivariable logistic regression models were performed on study outcomes. Data were analysed using Stata 15.1 software (Stata Statistical Software: Release 14. College Station, TX: Stata Corp LP). Finally, the fourth objective applied a qualitative descriptive design through use of in-depth interviews among FSWs, who were accessing HIV services through differentiated service delivery models in primary health facilities and drop-in centres in Kampala. We purposively sampled 2 health facilities and 2 drop-in centres and following the principle of data saturation, 24 FSWs were interviewed. Data analysis was conducted manually using framework analysis, and we applied an inductive approach which involved systematically reviewing the code framework, reduction, and interpretation of the data. Results: From the systematic review, the results showed variations in the effectiveness of community-based interventions along the various stages of HIV care cascade. The level of effectiveness was more pronounced in HIV testing and ART use; with average effectiveness observed in HIV diagnosis, than it is for linkage to care and viral load suppression. In addition, the interventions tended to be more impactful if they were provided in a combination of various strategies unique for each HIV care cascade stage. Among the sample of two hundred study participants from the adherence to HIV testing guidelines study, 88% of the study participants reported their HIV testing status; of these, 56% adhered to the HIV testing guidelines, having tested three or more times in the 12 months preceding the survey. Attaining a secondary education was associated with adherence to HIV testing guidelines [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.01 – 3.44; P = 0.047]. Testing for sexually transmitted infection in the preceding 3 months (OR: 2.13, 95% CI: 0.95 – 4.74, P = 0.065) and accessing HIV testing at a drop-in centre (OR: 5.90, 95% CI: 0.71 – 49.1; P = 0.101) were associated with higher odds of adherence to the HIV testing guidelines, although the association was not significant. Results from the study on retention and non-viral suppression showed retention of 85.1% (n = 234) at six months, corresponding to LTFU of 14.9% (n = 41) within the same period. Retention decreased with duration of being in care to 73.5% (n = 202) at 24 months, translating to LTFU of 26.5% (n = 73). Viral load testing coverage was 62% (n = 132) and of these, 90.9% (n = 120) were virally suppressed. Factors associated with LTFU at <0.2 significance level in univariable logistic regression model were age, marital status, education level, having treatment supporter, having a telephone contact, WHO stage at baseline, and having been diagnosed with TB during the study period. In multivariable logistic regression model, age (OR: 0.56, 95% CI: 0.031 - 1.00, p = 0.049), marital status (OR: 0.46, 95% CI: 0.23 - 0.89, p = 0.021), having telephone contact (OR: 0.22, 95% CI: 0.07 - 0.70, p = 0.010) and WHO stage at baseline (OR: 0.11, 95% CI: 0.01 - 0.97, p = 0.046), were significantly associated with LTFU at 0.05 significance level after adjusting for other factors. Factors associated with viral load suppression in univariable logistic regression models included age, having telephone contact, lost to follow up, and reason for lost-to-follow-up at <0.2 level of significancy. Age at enrolment remained statistically significant in multivariable logistic regression model (OR: 0.09, 95% CI: 0.01 – 0.82 P = 0.033) at 0.05 level of significance. Findings from the qualitative phase of the research study showed that HIV services provided through community based Differentiated Service Delivery (DSD) models were perceived to be of low quality, with a non-comprehensive package of HIV services for FSWs which did not match FSWs’ needs, preferences, and health risks. In addition, services were provided irregularly with compromised privacy and being provided by health workers who were perceived to have less than adequate specialised skills. Further, the process of deciding on how and what services should be provided through community DSD models targeting FSWs, the latter were not part of the process. Consequently, FSWs preferred facility-based models even though community DSD models were considered to be as a more convenient and a less costly option for access to HIV services and were thought to be a good complementary option if the quality of services provided in the community would be improved. Conclusion: Evidence brought forward in this research project shows that the effect of community-based interventions varies across the various stages of HIV care cascade. Therefore, it is critical to consistently monitor, review, and evaluate strategies under implementation to identify and realign those that have long term impact in improving HIV services access along the care continuum for FSWs. In addition, the suboptimal retention and viral load testing coverage underscores the need to improve the quality of services provided under differentiated care models, by ensuring that services are tailored to FSWs individual preferences, needs, and contexts.
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    Model-based inference on the impact of early access to antiretroviral therapy to all on HIV incidence among adolescent girls and young women in Eswatini
    (Stellenbosch : Stellenbosch University, 2021-04) Chibawara, Trust; Nyasulu, Peter; Kajungu, Dan; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Global Health. Epidemiology and Biostatistics.
    ENGLISH SUMMARY: Introduction: The introduction of antiretroviral drugs has enabled people living with HIV (PLHIV) to have a much better prognosis. As such, the use of antiretroviral drugs has resulted in the decline of global HIV incidence over the last decade. Whilst this achievement is important, the role of the widespread use of antiretroviral drugs on the HIV epidemic among adolescent girls and young women is still unknown. This study aimed to evaluate the impact of Early Access for all HIV-positive Adults to Antiretroviral (EAAA) on HIV incidence among adolescent girls and young women in Eswatini. Methods: To accomplish our research objectives, this research provided elaborate mathematical concepts that are multidisciplinary in nature and included evidence based systematic review, statistics, data science and public health approaches. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines was used for the systematic review. Using Simpact, an individual-based, event-driven, stochastic simulation tool, a specially designed HIV transmission model was adopted to simulate the heterosexual transmission of HIV in Eswatini. The application of a simplified model calibration approach combined clinical, biological, and behavioural indicators from the Eswatini implementation study called “Maximizing Antiretroviral Treatment for Better Health and Zero New HIV Infection: Early Access to Antiretroviral Treatment for All (MaxART EAAA)” and Eswatini demographic summary statistics to infer the impact of EAAA on HIV incidence in adolescent girls and young women. Results: The results of the systematic review showed that globally, there was no published or unpublished research found on the impact of the use of ART by HIV positive adults on HIV incidence in adolescent girls and young women. While on the other hand, our model which aimed to evaluate the impact of EAAA on older men aged 18 years and above in Eswatini showed a 45% (95% Confidence interval (CI): 37-55) reduction on HIV incidence among the adolescent girls and young women aged 15-24-years-old as opposed to CD4 cell count threshold for ART eligibility (Standard of care). Furthermore, simulated data showed that early access to ART has a similar impact of 47% (95% CI: 33-59) reduction in HIV incidence among adolescent boys and young men of the same age group. Conclusion: This study has demonstrated the impact of EAAA as a strategy to reduce new HIV infections among adolescent girls and young women aged between 15-24-years-old in the Eswatini population. These findings reinforce the need to adopt provisions for early initiation of ART treatment among HIV infected adults as a catalyst to minimize transmission of HIV to the adolescent population. Data from this study also highlight the need for other countries in the region who are faced with similar challenges of harbouring a high HIV prevalence to adopt EAAA as it has shown to be an effective approach to reduce HIV/AIDS incidence in the population. While these benefits are applaudable, we do recognize that HIV/AIDS treatment on its on is not sufficient; therefore, behavioural changes that guard against age-disparate relationships should be reinforced.