Patients with poor adherence level at start of second-line ART were 3.6 times (AHR = 3.63, 95% CI = 1.89–6.96) more likely to develop treatment failure compared to patients who had good/fair adherence level after adjusting for the effect of age, TB status, CD4 count and WHO stage (Table 4). This evidence concerns the gene CD4 and tuberculosis.