Increased risk of default among previously treated tuberculosis cases in the Western Cape Province, South Africa.
OBJECTIVE
To investigate, in two urban communities with high tuberculosis (TB) incidence and high rates of TB recurrence, whether a history of previous TB treatment is associated with treatment default.


METHODS
Retrospective cohort study of TB cases with an episode of treatment  recorded in the clinic-based treatment registers between 2002 and 2007. Probabilistic record linkage was used to ascertain treatment history of TB cases back to 1996. Based on the outcome of their most recent previous treatment episode, previously treated cases were compared to new cases regarding  their risk of treatment default.


RESULTS
Previous treatment success (adjusted odds ratio [aOR] 1.79; 95%CI 1.17-2.73), previous default (aOR 6.18, 95%CI 3.68-10.36) and previous failure (aOR 9.72, 95%CI 3.07-30.78) were each independently associated with treatment default  (P < 0.001). Other factors independently associated with default were male sex (P = 0.003) and age 19-39 years (P < 0.001).


CONCLUSIONS
Previously treated TB cases are at increased risk of treatment default, even after previous successful treatment. This  finding is of particular importance in a setting where recurrent TB is very common. Adherence to treatment should be ensured in new and retreatment cases to increase cure rates and reduce transmission of TB in the community.
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany. fl orian.marx@charite.de
F M
FM
Marx
R
R
Dunbar
A C
AC
Hesseling
D A
DA
Enarson
K
K
Fielding
N
N
Beyers
D000328:Adult; D000367:Age Factors; D000995:Antitubercular Agents / Q000627:therapeutic use*; D023801:Directly Observed Therapy; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008498:Medical Record Linkage; D055118:Medication Adherence; D015999:Multivariate Analysis; D016017:Odds Ratio; D012008:Recurrence; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013019:South Africa / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D014504:Urban Health; D055815:Young Adult
D000995:Antitubercular Agents