Incidence and Determinants of Lost to Follow Up Among Adults Living with HIV/AIDS on Antiretroviral Therapy in Iringa Region, Tanzania.

Background: Globally, HIV/ AIDS continues to be a public health problem and as of June 2023 Iringa has a total of 81,852 clients receiving Care and treatment from DHIS2 source. Antiretroviral therapy (ART) is the backbone of management of HIV and clients need to have high adherence (≥ 95%) for ART treatment outcome to be positive. Most previous studies have identified that Lost to follow up (LTFU) from ART treatment programs is the main challenge faced by most ART treatment programs in resource constrained countries. Tanzania is reported to have high rate of LTFU among PLHIV on ART, and factors associated with LTFU in areas with high prevalence of HIV/AIDs like Iringa region are not well known and documented  Objectives: This study intends to estimate the incidence rate of LTFU among PLHIV on ART and to identify factors associated with LTFU in Iringa region, Tanzania.  Method and Materials: The Study design was a retrospective cohort design among PLHIV initiated in treatment from 2017 to 2020 in Iringa region. The regional HIV treatment dataset was retrieved from CTC2 electron database in excel format, cleaned, coded and imported into IBM SPSS STATISTICS version 26 for analysis. Numerical variables were summarized using median (IQR) while categorical variables were analyzed and reported as proportions. Incidence rates were calculated and used as measure of magnitude of the problem, while survival analysis and log-rank tests were used to compare rate of LTFU among adult living with HIV on ART with different level of initial exposures. Any variable associated with LTFU at significant level of P < 0.2 in univariate analysis was subjected to multivariate Cox proportion regression analysis in order to control potential confounders. Any variable which showed association with LTFU at significant level of p value < 0.05 in multivariate Cox regression analysis was regarded as independently associated with LTFU  Results: A total of 36,043 participants were included in the analysis, the overall incidence rate of lost to follow up among adult PLHIV initiated ARV is 2.80, 95% CI (2.68 – 2.93) per 100-person years. This incidence rate was observed to vary based on duration of follow up (time), age, sex and residence. LTFU increased with increasing time of follow, it was 0.34, 95% CI (0.26 – 0.44) per 100 person-years at initial 6 months of follow up, then increased to 1.59, 95% CI (1.40 – 1.81) per 100 person-years at 6 – 12 months of follow up, which increased further to 2.56, 95% CI (2.35 – 2.78) per 100 person-years at 12 – 24 months of follow up, and the highest incidence was 4.45, 95% CI (4.08 – 4.85) per 100 person-years, which was observed at the 24 – 36 months of follow up. In terms of factors associated with LTFU, young age (aged 18 – 24 years) at the time of ARV initiation (adjusted HR = 3.95, 95% CI 2.95– 5.28, P < 0.001, residents of Mufindi DC (adjusted HR = 1.39, 95% CI 1.16 – 1.66, P < 0.001), Mafinga TC (adjusted HR = 4.04, 95% CI 3.3 – 4.90, P < 0.001), and Kilolo DC (adjusted HR = 2.11, 95% CI 1.77 – 2.53, P < 0.001), as well as PLHIV initiated NNRTI antiretroviral regimen (adjusted HR = 2.93, 95% CI 2.64 – 3.26, P < 0.001) and PLHIV at WHO clinical stage I (adjusted HR = 3.77, 95% CI 2.80 – 5.09, P < 0.001), stage II (adjusted HR = 2.59, 95% CI 1.89 – 3.53, P < 0.001) and stage III (adjusted HR = 1.62, 95% CI 1.21 – 2.17, P = 0.001) at the time of ARV initiation, were significantly associated with increased Hazard Ratio (HR) of being LTFU. Conclusion and Recommendation: LTFU remains a challenge in care and treatment of PLHIV in the studied area. Younger age, male sex, PLHIV initiated NNRTI-regimen and PLHIV residing in Mufindi DC, Mafinga TC and Kilolo DC were factors associated with increased risk of LTFU. Moreover, Lost to Follow Up is shown to decrease with increasing WHO stage at recruitment. Interventions targeting these factors are important to address the problem