Understanding why and how adoleschent-friendly condition of health services affect outcomes among adolescents and young adults living with HIV in Nigeria

Introduction: Despite global progress in the fight against HIV, adolescents and young adults (AYA) continue to bear a disproportionate burden of HIV and have worse HIV-related outcomes compared to other age groups. This demographic, especially girls in certain regions, face heightened risks of new HIV infections, lag behind in global reduction in AIDS-related deaths, in knowing their HIV status, initiating treatment if infected, and achieving viral suppression compared to other age groups. This issue is particularly pressing in Nigeria, where AYA constitute a significant portion of the country's HIV burden, experiencing high and escalating mortality rates and poorer treatment outcomes along the UNAIDS 90-90-90 cascade of care. The roots of this disparity are multifaceted, stemming from multiple and complex needs that span individual, family, structural/community, and healthcare levels. Factors such as legal and cultural barriers undermine AYA autonomy over their sexual and reproductive health rights, including HIV. Social and economic pressures heightens their vulnerability to risky behaviors, disrupting family dynamics, hindering effective communication and support for AYA living with HIV, especially in high stigma setting. Additionally, challenges within the healthcare system, such as unclear guidelines for transitioning young people with HIV to adult care, result in inconsistent and uncoordinated services, impeding access to necessary care and support.

Although combination HIV prevention packages have been implemented to address these multiple and complex barriers facing AYA, evidence suggests limited effectiveness, especially when compared to older or general populations. Youth-friendly health services (YFHS) have emerged as a promising approach to enhance the effectiveness of combination interventions. However, implementing effective YFHS globally and in Nigeria encounters its own set of challenges. The absence of consensus on YFHS definition, optimal implementation strategies, and criteria for measuring effectiveness complicates efforts to identify core components and maximize impact. Consequently, significant knowledge and practice gaps persist regarding the most effective strategies for YFHS and how to scale them up.

Objectives: This thesis addresses the gaps in YFHS knowledge and practice by investigating how YFHS can be more effectively implemented within healthcare facilities in Nigeria, recognizing the pivotal role healthcare facilities play in shaping the HIV outcomes of AYA living with HIV. Specifically, the thesis seeks to identify the minimum combination of structural and organizational elements within healthcare facilities that guarantees optimal outcomes for AYA living with HIV. These elements can then form the essential components of a comprehensive YFHS package.

The study is guided by two research questions (1) To what extent do variations in both facility characteristics and service delivery practices contribute to disparities in HIV-related outcomes among adolescents and young adults across Nigeria? (2) What combination of facility-level characteristics, and service delivery processes are associated with the best HIV-related outcomes among AYA living with HIV in Nigeria?

Methods: The thesis adopted a Method Plurality (MP) approach, combining various research methods from different epistemologic and theoretical perspectives, to pursue three interconnected objectives required to address the two research questions. The methods selected include survey analysis, multilevel modelling, latent class modelling, mixed methods research, realist evaluation and qualitative comparative analysis.

Results: The results of the study have been published or accepted in four peer reviewed journal articles, Articles 1-4.

Article 1 was a national survey of structures and processes in the transitioning of HIV clinical care for adolescents to adult care (i.e. a related practice and indicator of youth friendliness of services). The article showed that while none of the facilities meet recommended standards for transitioning care for adolescents, inter-facility differences exist in the structures and processes in the transitioning of clinical care for adolescents to adult care.

Building upon the main findings of Article 1, Article 2 used multilevel modelling and multiple group analysis to quantify the extent to which observed inter-facility variation account for observed disparities in HIV treatment outcomes (continuity of care and viral load suppression) between AYA. The article demonstrates that inter-facility variations are associated with differences in outcomes (continuity of care and viral load suppression) among AYA living with HIV. Significantly, the effect of variation in inter-facility characteristics was found to be more pronounced than the effect of variation in individual-level characteristics.

Using, a nationally representative data from Nigeria AIDS Indicator and Impact Survey (NAIIS2018), Article 3 used Latent class analysis to assess barrier reported by AYA in accessing HIV testing services. The barriers served as proxy for the underlying combinations of gaps in facility characteristics and service delivery processes. Article 3 identified four distinct AYA subgroups based on the combination of barriers they reported in accessing HIV testing services.. The article found that barrier combination was associated with subgroup sexual behaviour but did not find an association between barrier combination and the HIV status (the outcome).

Article 4 combined mixed methods, realist evaluation and qualitative comparative analysis to explore how different aspects of YFHS models combine to achieve optimal outcomes(adherence and viral suppression) among AYA living with HIV. Article 4 showed a key finding: there is no single minimum combination of youth-friendly processes, interventions, or characteristics that universally leads to optimal outcomes. The article showed that while privacy and confidentiality were necessary or a near-universal condition to achieve viral suppression, they were not sufficient on their own, but must be combined with other facility characteristics and service delivery aspects (i.e. differentiated services, peer delivered services, intrinsic and extrinsic motivation) along four different pathways to achieve optimal viral load suppression outcomes. Cross-cutting findings of the thesis highlight the link between autonomy-agency, autonomy-enhancing interventions, behavioral patterns, and observed outcomes among AYA living with HIV.

Conclusions: The thesis yields two main conclusions that carry significant implications for YFHS policy and practice. Firstly, the structure and organization of healthcare facilities, including care provider related factors and attitudes, exert a considerable impact on healthcare outcomes in AYA, often more than individual behaviours or characteristics do. The second conclusion is that there is not a singular combination of interventions or contextual conditions that consistently lead to optimal outcomes. To achieve the optimal outcomes, interventions must be adapted to young people’s needs and specific contextual conditions where the intervention is to be delivered.

These conclusions emphasizes the need to enhance the conditions of health facilities, with minimum standards incorporating the cross-cutting conditions: ensuring privacy and confidentiality, integrating autonomy/agency-building interventions such as peer-led or peer delivered differentiated services to enhance access to care. Furrhermore, the conclusions emphasize that specific interventions aimed at achieving YFHS goals should not adopt a one-size-fits-all approach but rather be tailored to suit the unique circumstances of each healthcare facility and its AYA population.