Pretreatment Lost to Follow-up Tuberculosis Patients, Lusaka, Zambia, 2024: A Retrospective Cohort Study

Background Treatment outcomes, particularly lost to follow-up (LTFU) of tuberculosis (TB) patients, are one of the most fundamental indicators related to TB control. However, national TB programs often ignore those who once come to a health facility and were diagnosed with TB but never come back to the facility to commence anti-TB treatment (i.e. pretreatment [PT] LTFU). We conducted a study to determine the proportions of bacteriologically confirmed PT-LTFU patients with TB found at four facilities in Lusaka, Zambia, in 2024. This is the first multifacility 2024 cohort assessing PT-LTFU trends in urban Zambia. Methods This was a retrospective cohort study, in which the TB laboratory and treatment registers at the study sites were cross-matched. Those who did not commence anti-TB treatment within 14 days after laboratory diagnosis were defined as PT-LTFU patients. Results A total of 1166 bacteriologically positive TB patients were eligible for the study. Of these, 1158 (99.3%) patients were diagnosed using Xpert MTB/RIF and 8 (0.7%) by the presence of lipoarabinomannan. Their ages ranged from 6 months to 90 years; 850 (72.9%) patients were male and 26 (2.2%) were aged Conclusion The proportion of PT-LTFU was 12.5% in the four facilities in Lusaka, Zambia, in 2024. This was slightly higher than in a previous study conducted in Lusaka in 2020. The proportions of PT-LTFU were significantly higher among those diagnosed as lower positives with Xpert MTB/RIF, probably because the patients may not have been convinced they had TB. There is a need to strengthen the capacity of laboratories to provide same-day results for patients to reduce the rate of PT-LTFU. Furthermore, there should be strengthened departmental linkages and improved documentation of patients' contact details at health facilities to facilitate patient follow-up for TB service provision and tracing. Enhanced laboratory turnaround, real-time linkage of diagnostic and treatment registers, and improved patient tracing are essential to reduce PT-LTFU and align with the World Health Organization End-TB targets.