Biological Monitoring of Patients under First-Line Antituberculous Treatment in Chad from 2021 to 2022

Tuberculosis (TB) remains a major public health challenge in Africa, particularly in Chad. The success of first-line antituberculous treatment relies on rigorous clinical follow-up and regular laboratory monitoring. This study aims to assess the biological follow-up of patients undergoing first-line antituberculous treatment in Chad, using a large provincial cohort and a prospective hospital cohort at the CHU-RN, to inform strategies for improving TB management in Chad. A mixed cross-sectional retrospective and prospective study was conducted using data from TB treatment centers across ten Chadian provinces from January 2021 to June 2022, along with samples collected at CHU-RN in N’Djamena from March to September 2021. Data included demographic, clinical, and biological information from patients under first-line antituberculous treatment. Biological monitoring was assessed according to the recommendations of the National Tuberculosis Control Program (PNT) of Chad and the WHO. Among 5,811 provincial patients, the overall performance rate of recommended biological tests (AFB smear and GeneXpert) was 52.8%, with GeneXpert performed in only 5.1% of cases and rifampicin resistance detected in 3.36% of those tested. At CHU-RN, 111 patients were enrolled, and 95.5% received biological monitoring consistent with guidelines, although follow-up markedly declined after the second month. Follow-up was particularly inadequate among men, patients with low levels of education, or those without health insurance, but these associations were not tested using multivariate analysis. Biological follow-up of patients on antituberculous therapy in Chad remains insufficient, potentially compromising treatment efficacy and promoting resistance emergence. Strengthened strategies targeting vulnerable populations and improved access to care are essential to enhance biological monitoring and TB treatment outcomes in Chad.