CD4 and tuberculosis: Second, there were missing data on key variables which include CDST results, socio-economic status, WHO clinical staging, CD4 cell count, timing of ART in relation to MDR-TB treatment commencement, nutritional status, MDR-TB drug regimens and their dosages, data on virological, immunological or clinical failure of patients initiated on ART and radiological findings of TB lesions–all which are important factors which may be related to MDR-TB treatment outcomes.