Pre-treatment lost to follow-up tuberculosis patients, Chongwe, Zambia, 2017: a retrospective cohort study

Four tuberculosis (TB) diagnostic health facilities of the Chongwe District, Zambia.

To determine the frequency of bacteriologically confirmed TB patients lost to follow-up (LTFU) before treatment from January to December 2017.

This is a retrospective cohort study involving the review of TB registers. Information on presumptive TB patients who tested positive either by smear microscopy or Xpert^® MTB/RIF assay was extracted from the laboratory TB registers of the TB diagnostic facilities and cross-matched with the TB treatment registers of TB treatment facilities.

Two hundred and seventeen bacteriologically confirmed TB patients were found in the laboratory TB registers. Of these, 145 (67%) were males and seven (3%) were children; 177 (81%) patients were diagnosed using Xpert, while the remaining 40 (19%) were diagnosed using sputum smear microscopy. A total of 71 (33%) were not linked to treatment. Those diagnosed using smear microscopy were 2.5 times (95% CI 1.1-5.3) more likely to be LTFU before treatment than those diagnosed using Xpert.

About one third of TB patients who were not linked to treatment could potentially extend the duration of bacilli transmission in their communities. National TB control programmes should consider including LTFU patients before treatment in routine monitoring and evaluation.