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Retreatment Tuberculosis Cases*
Factors Associated With Drug Resistance and Adverse Outcomes
Afranio L. Kritski, MD, PhD; Luis Sergio Rodrigues de Jesus, MD; Monica K Andrade, Eduardo Werneck-Barroso, MD; Maria Armanda Monteiro S. Vieira, MD; Alice Haffner, MS; and Lee W. Riley, MD
Study objective: Risk factors associated with treatment failure and multidrug-resistant tuberculosis (MDR-TB) were examined among HIV-seronegative patients who were previously treated for tuberculosis (TB).
Design: Prospective, cohort study of patients referred to the study hospital for retreatment of TB between March 1986 and March 1990.
Patients: The patients belonged to three groups, according to outcomes following their previous
treatment: 37 patients who abandoned treatment or suffered relapse after completion of therapy (group A), 91 patients who failed to respond to the first-line drug regimen (group B), and 78 patients who failed to respond to the second-line drug regimen (group C).
Results: Patients with Mycobacterium tuberculosis strains resistant to rifampin and isoniazid were found in 2 (6%) in group A, 29 (33%) in group B, and 49 (65%) in group C. Cure was achieved in 77% in group A, 54% in group B, and 36% in group C. Death occurred in none of the patients in group A, 8% in group B, and 24% in group C. In a multivariate logistic regression analysis, unfavorable response (failure to sterilize sputum culture, death, and abandonment) was significantly associated with infection with a multidrug-resistant M tuberculosis strain (p=0.0002), cavitary disease (p=0.0029), or irregular use of medications (p<0.0001).
Conclusion: These observations show that a previous treatment outcome and current clinical and epidemiologic histories can be used to predict the development of MDR-TB and adverse outcomes in patients undergoing retreatment for TB. Such information may be useful for identifying appropriate patient candidates for programs such as directly observed therapy. (CHEST 1997; 111:1162-67)
Key words: DOT; multidrug-resistant TB; TB retreatment; tuberculosis
Abbreviations: DOT=directly observed therapy; EMB=ethambutol; INH=isoniazid; MDR=multidrug-resistant; MDR-TB=multidrug-resistant tuberculosis; PZA=pyrazinamide; RIF=rifampin; SM=streptomycin; TB=tuberculosis
Patients needing retreatment for tuberculosis (TB) present with a variety of previous TB treatment outcome histories. One such outcome is the development of multidrug-resistant (MDR)-TB; previous treatment is an important risk factor for MDR-TB.1-4
However, clearly not all such patients develop MDR-TB, and their previous treatment history and outcome may provide clues as to...