Estimation of HIV prevalence and burden in Nigeria: a Bayesian predictive modelling study.

Background: The cost of population-based surveys is high and obtaining funding for a national population-based survey may take several years, with follow-up surveys taking up to five years. Survey-based prevalence estimates are prone to bias owing to survey non-participation, as not all individuals eligible to participate in a survey may be reached, and some of those who are contacted do not consent to HIV testing. This study describes how Bayesian statistical modeling may be used to estimate HIV prevalence at the state level in a reliable and timely manner. Methods: We analysed national HIV testing services (HTS) data for Nigeria from October 1, 2020, to September 30, 2021, to derive state-level HIV seropositivity rates. We used a Bayesian linear model with normal prior distribution and Markov Chain Monte Carlo approach to estimate HIV state-level prevalence for the 36 states +1 FCT in Nigeria. Our outcome variable was the HIV seropositivity rates and we adjusted for demographic, economic, biological, and societal covariates collected from the 2018 Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS), 2018 Nigeria Demographic and Health Survey (NDHS) and 2016-17 Multiple Indicator Cluster Surveys (MICS). The estimated population of 15-49 years olds in each state was multiplied by estimates from the estimated prevalence to generate state-level HIV burden. Findings: Our estimated national HIV prevalence was 2.1% (95% CI: 1.5-2.7%) among adults aged 15-49 years in Nigeria, which corresponds to approximately 2 million people living with HIV, compared to previous national HIV prevalence estimates of 1.4% from the 2018 NAIIS and UNAIDS estimation and projection package PLHIV estimation of 1.8 million in 2022. Our modelled HIV prevalence in Nigeria varies by state, with Benue (5.7%, 95% CI: 5.0-6.3) having the highest prevalence, followed by Rivers (5.2%, 95% CI: 4.6-5.8%), Akwa Ibom (3.5%, 95% CI: 2.9-4.1%), Edo (3.4%, 95% CI: 2.9-4.0%) and Taraba (3.0%, 95% CI: 2.6-3.7%) placing fourth and fifth, respectively. Jigawa had the lowest HIV prevalence (0.3%), which was consistent with prior estimates. Interpretation: This model provides a comprehensive and flexible use of evidence to estimate state-level HIV seroprevalence for Nigeria using program data and adjusting for explanatory variables. Thus, investment in program data for HIV surveillance will provide reliable estimates for HIV sub-national monitoring and improve planning and interventions for epidemiologic control. Funding: This article was made possible by the support of the American people through the United States Agency for International Development (USAID) under the U.S. President's Emergency Plan for AIDS Relief (PEPFAR).

Pregnant women with HIV in rural Nigeria have higher rates of antiretroviral treatment initiation, but similar loss to follow-up as non-pregnant women and men.

BACKGROUND: We examined antiretroviral therapy (ART) initiation and retention by sex and pregnancy status in rural Nigeria. METHODS: We studied HIV-infected ART-naïve patients aged ≥15 years entering care from June 2009 to September 2013. We calculated the probability of early ART initiation and cumulative incidence of loss to follow-up (LTFU) during the first year of ART, and examined the association between LTFU and sex/pregnancy using Cox regression. RESULTS: The cohort included 3813 ART-naïve HIV-infected adults (2594 women [68.0%], 273 [11.8%] of them pregnant). The proportion of pregnant clients initiating ART within 90 days of enrollment (78.0%, 213/273) was higher than among non-pregnant women (54.3%,1261/2321) or men (53.0%, 650/1219), both p<0.001. Pregnant women initiated ART sooner than non-pregnant women and men (median [IQR] days from enrollment to ART initiation for pregnant women=7 days [0-21] vs 14 days [7-49] for non-pregnant women and 14 days [7-42] for men; p<0.001). Cumulative incidence of LTFU during the first year post-ART initiation was high and did not differ by sex and pregnancy status. Persons who were unemployed, bedridden, had higher CD4+ counts, and/or in earlier WHO clinical stages were more likely to be LTFU. CONCLUSIONS: Pregnant women with HIV in rural Nigeria were more likely to initiate ART but were no more likely to be retained in care. Our findings underscore the importance of effective retention strategies across all patient groups, regardless of sex and pregnancy status.

Haemoglobin recovery among HIV-1 infected patients on zidovudine-based antiretroviral therapy and other regimens in north-central Nigeria.

We conducted a study to assess trends in haemoglobin recovery among HIV-infected patients initiated on zidovudine-based combination antiretroviral therapy (cART) stratified by baseline haemoglobin level. Haemoglobin data from non-pregnant adult patients initiating cART in rural north-central Nigeria between June 2009 and May 2011 were analysed using a linear mixed effects model to assess the interaction between time, zidovudine-containing regimen and baseline haemoglobin level on the outcome of subsequent haemoglobin level. Best-fit curves were created for baseline haemoglobin in the 10th, 25th, 75th and 90th percentiles. We included 313 patients with 736 measures of haemoglobin in the analysis (239 on zidovudine and 74 on non-zidovudine-containing regimens). Median haemoglobin increased over time in both groups, with differences in haemoglobin response over time related to baseline haemoglobin levels and zidovudine use (p = 0.003). The groups of patients on zidovudine at the 10th and 90th percentiles had downward sloping curves while all other groups had upward trending haemoglobin levels. Although haemoglobin levels increased overall for patients on zidovudine-containing regimens, for those in the 10th and 90th percentiles haemoglobin levels trended downward over time. These results have implications for decisions regarding when to initiate, switch from or avoid the use of zidovudine.

Risk factors for delayed initiation of combination antiretroviral therapy in rural north central Nigeria.

BACKGROUND: Timely initiation of combination antiretroviral therapy (ART) in eligible HIV-infected patients is associated with substantial reduction in mortality and morbidity. Nigeria has the second largest number of persons living with HIV/AIDS in the world. We examined patient characteristics, time to ART initiation, retention, and mortality at 5 rural facilities in Kwara and Niger states of Nigeria. METHODS: We analyzed program-level cohort data for HIV-infected ART-naive clients (≥15 years) enrolled from June 2009 to February 2011. We modeled the probability of ART initiation among clients meeting national ART eligibility criteria using logistic regression with splines. RESULTS: We enrolled 1948 ART-naive adults/adolescents into care, of whom, 1174 were ART eligible (62% female). Only 74% of the eligible patients (n = 869) initiated ART within 90 days after enrollment. The median CD4 count for eligible clients was 156 cells/µL (interquartile range: 81-257), with 67% in WHO stage III/IV disease. Adjusting for CD4 count, WHO stage, functional status, hemoglobin, body mass index, sex, age, education, marital status, employment, clinic of attendance, and month of enrollment, we found that immunosuppression [CD4 350 vs. 200, odds ratio (OR) = 2.10, 95% confidence interval (CI): 1.31 to 3.35], functional status [bedridden vs. working, OR = 4.17 (95% CI: 1.63 to 10.67)], clinic of attendance [Kuta Hospital vs. referent: OR = 5.70 (95% CI: 2.99 to 10.89)], and date of enrollment [December 2010 vs. June 2009: OR = 2.13 (95% CI: 1.19 to 3.81)] were associated with delayed ART initiation. CONCLUSIONS: Delayed initiation of ART was associated with higher CD4 counts, lower functional status, clinic of attendance, and later dates of enrollment among ART-eligible clients. Our findings provide targets for quality improvement efforts that may help reduce attrition and improve ART uptake in similar settings.

Higher rates of AIDS during the first year of antiretroviral therapy among migrants: the importance of tuberculosis.

OBJECTIVE: In lower-income countries rates of AIDS-defining events (ADEs) and death are high during the first year of combination antiretroviral therapy (ART). We investigated differences between foreign-born (migrant) and native-born (nonmigrant) patients initiating ART in Europe, the US and Canada, and examined rates of the most common ADEs and mortality during the first year of ART. DESIGN: Observational cohort study. METHODS: We studied HIV-positive adults participating in one of 12 cohorts in the Antiretroviral Therapy Cohort Collaboration (ART-CC). RESULTS: Of 48 854 patients, 25.6% were migrants: 16.1% from sub-Saharan Africa, 5.6% Latin America, 2.3% North Africa/Middle East, and 1.6% Asia. Incidence of ADEs during the first year of ART was 60.8 per 1000 person-years: 69.9 for migrants and 57.7 for nonmigrants [crude hazard ratio (HR) 1.18; 95% confidence interval (CI) 1.08-1.29], adjusted HR (for sex, age, CD4, HIV-1 RNA, ART regimen, prior ADE, probable route of infection and year of initiation, and stratified by cohort) 1.21 (95% CI 1.09-1.34). Rates of tuberculosis were substantially higher in migrants than nonmigrants (14.3 vs. 6.3; adjusted HR 1.94; 95% CI 1.53-2.46). In contrast, mortality was higher among nonmigrants than migrants (crude HR 0.71; 95% CI 0.61-0.84), although excess mortality was partially explained by patient characteristics at start of ART (adjusted HR 0.91; 95% CI 0.76-1.09). CONCLUSIONS: During the first year of ART, HIV-positive migrants had higher rates of ADEs than nonmigrants. Tuberculosis was the most common ADE among migrants, highlighting the importance of screening for tuberculosis prior to ART initiation in this population.

Virologic, immunologic and clinical responses in foreign-born versus US-born HIV-1 infected adults initiating antiretroviral therapy: an observational cohort study.

INTRODUCTION: Mortality rates within the first year of combination antiretroviral therapy (cART) initiation are several-fold higher in resource-limited countries than in resource-replete settings. However studies in western countries examining virologic, immunologic and clinical responses after cART initiation in indigenous versus non-indigenous populations have shown mixed results. This study aimed to determine whether there is a difference in these outcomes in a United States setting between foreign-born and US-born patients. METHODS: This retrospective observational cohort study of HIV-1 infected adults in one urban clinic in the United States compared virologic suppression, immune recovery and rates of AIDS defining events (ADEs) within the first year of cART using linear mixed effect models, log rank tests and Cox proportional hazard models. Data were analyzed for 94 foreign-born and 1242 US-born patients. RESULTS: Foreign-born patients were younger (31.7 years versus 38.5 years), more often female (38.3% versus 27.1%), less often injection drug users (3.2% versus 9.5%) or men who have sex with men (19.0% versus 54.5%), and had higher loss to follow-up rates (14.9% versus 6.2%). No significant differences were detected between the groups in suppression of plasma HIV-1 RNA, CD4+ cell recovery or development of ADEs. CONCLUSIONS: During the first year on cART, virologic suppression, immune recovery and development of ADEs were comparable between foreign-born and US-born patients in care in a US clinic. Differential rates of loss to follow-up warrant further investigation in the foreign-born population.

Access to care issues for African American communities: implications for STD disparities.

Reduced access to care is a major contributor to health disparities in black communities. This review discusses factors that serve to diminish access to care among blacks in the context of STD disparities and highlights strategies to improve access to STD care. At the individual level, structural factors such as poverty, lack of insurance, and lack of a regular source of care are known to decrease health service utilization and have been identified as barriers to STD care as well. Other individual level factors that influence access to care, particularly for STDs, include concerns about confidentiality and privacy, perceptions of discrimination, and perceptions of risk. At the health system level, availability of services, organizational inefficiencies, and staff perceptions affect access. Strategies to improve access to STD care include expanding services in high-risk nontraditional venues, developing multilevel partnerships, incorporating STD services into routine healthcare, integrating services with HIV, improving the quality of public STD clinic care, and ultimately addressing the broader underlying factors that contribute to health disparities.