Human Immunodeficiency Virus (HIV) infection remains a major global public health challenge. According to the UNAIDS 2023 report, approximately 39.9 million people were living with HIV worldwide, with 30.7 million receiving antiretroviral therapy (ART) [1] . These therapies have transformed HIV from a rapidly fatal illness into a controllable chronic condition, reducing morbidity and significantly improving life expectancy and quality of life for people living with HIV (PLWH) [2] [3] . The main goals of ART are to prevent progression to AIDS, restore immune function, and maintain an undetectable viral load [4] . However, treatment adjustments may become necessary due to virological failure, side effects, drug interactions, or the emergence of resistance [5] [6] . Recent advances, particularly the introduction of Dolutegravir (DTG), have enabled the use of more effective, better-tolerated, and simpler regimens [7] [8] . Switching ART regimens is therefore a crucial step in HIV care. It must be tailored to the patient’s virological and clinical profile, while considering comorbidities, coinfections, adherence levels, and treatment history [9] [10] . Patient education plays a fundamental role in this process, directly impacting treatment outcomes [11] .

Despite therapeutic progress, there is still no definitive cure for HIV. ART remains the only effective means of long-term infection control [10] . In Chad, HIV is a generalized epidemic with a prevalence of 1.6% among people aged 15 to 49, disproportionately affecting women (1.8%) compared to men (1.3%) according to the 2014-2015 DHS-MICS survey [12] . To address the epidemic, the Chadian government made ART free of charge in May 2007, leading to a rise in the number of PLWH on treatment. By December 2023, a total of 69,188 patients were receiving ART in the country [13] . However, limited data are available regarding treatment switching practices in care settings. This study aims to analyze changes in ARV regimens among patients followed at CEDIAM in N’Djamena to improve understanding and inform better strategies for HIV care in Chad.

Among the 573 people living with HIV (PLWH) followed at CEDIAM, 253 patients underwent a change in at least one antiretroviral (ARV) molecule, representing an overall frequency of 44.15%. This proportion highlights the significant rate of therapeutic adjustments in the long-term management of HIV, often driven by continuously evolving national and international guidelines [1] . The most represented age group was 37 to 47 years (43.5%), consistent with findings by Diallo et al. in Senegal (40.9%) [14] and slightly higher than that reported by Traoré in Mali (32%) . This predominance reflects the concentration of the epidemic among the sexually active population. In Chad, the highest prevalence is found in the 35 - 39 age group (2.9%), compared to 1.6% in the general population [12] . Additionally, the success of advanced testing strategies and improved access to care has enabled earlier identification of cases, including asymptomatic individuals [16] . Females accounted for 70% of the study population, similar to findings from Diemer et al. in the Central African Republic (69.8%) [17] and Maïga in Mali (73.46%) [18] . This female predominance is well documented and attributed to both biological vulnerability (e.g., genital anatomy, higher prevalence of STIs) and socioeconomic factors—such as poverty, gender inequality, and cultural practices like levirate or sororate, which increase exposure risk [19] [20] . Almost all patients resided in N’Djamena (96.8%), explained by both the location of CEDIAM in the capital and the fact that nearly one-third of PLWH in Chad live in this area [13] . As for HIV type, 99.2% of patients were infected with HIV-1, which aligns with the regional distribution in Central Africa as reported by Samaké (97.9%) and Boubacar (94.1%) in Mali [22] . The predominant reason for treatment change was the transition to Dolutegravir (DTG)-based regimens, accounting for 90.51% of cases. This transition reflects Chad’s national policy to shift toward the TLD regimen (TDF + 3TC + DTG), which has been in line with updated WHO recommendations since 2019 [23] . Chad officially adopted this directive in 2020, aiming to progressively replace older regimens containing efavirenz (EFV) or nevirapine (NVP), which have higher toxicity and lower genetic barriers to resistance [24] . Prior to this shift, most patients were on TDF/FTC/EFV (VIRADAY) (65.21%) or AZT/3TC/NVP (DUOVIR-N) (34.39%), consistent with earlier national guidelines [25] . Following the transition, 90.51% of patients were placed on the TLD regimen. This is slightly lower than the rate reported by Samaké in Mali (98%) , but higher than that found during Chad’s 2023 active file audit (62.6%) [26] . The difference may be explained by the fact that this study was conducted after the national protocol update in February 2023, which formally established TLD as the preferred first-line regimen [27] . Regarding the therapeutic line, 91.30% of patients remained on first-line treatment—higher than reported by Traoré (80.3%) and Bougoudogo et al. (65.86%) [28] . This could indicate good adherence to treatment and the effectiveness of support strategies implemented at CEDIAM, such as educational talks, personalized follow-up, and differentiated service delivery models, all of which enhance patient retention and therapeutic compliance [29] .

At CEDIAM, 91.3% of patients remained on first-line antiretroviral therapy. Over 61% had experienced a single treatment change, primarily motivated (90.5%) by the national transition to Dolutegravir-based regimens. These findings reflect strong alignment with national treatment protocols and satisfactory patient adherence.

It is essential that any ARV regimen change be conducted in strict compliance with national guidelines, combined with close clinical monitoring and continuous patient education, to ensure long-term treatment success and virological suppression.

We extend our heartfelt thanks to all the managers and staff of the Diocesan Center of N’Djamena for their support and for providing the necessary information for the completion of this study. We are also deeply grateful to the people living with HIV who kindly agreed to answer our questions and contribute to the successful finalization of the research.