Background: Multidrug resistant tuberculosis is a threat to tuberculosis control worldwide. In many studies, it has been suggested that inadequate treatment is a risk factor for the development of multidrug resistent tuberculosis. Objective: To identify the factors associated with inadequate treatment in a group of patients with multidrug resistent tuberculosis. Method: The authors identified all drug sensitivity test for tuberculosis performed at the Central Laboratory of the state of Ceará from 1990 to 1999. Retrospective and prospective analysis was performed, comparing the characteristics of adequately treated patients with those of inadequately treated patients. Multidrug resistance was defined as resistance to 2 drugs (rifampin and isoniazid) or more, using the Cox proportional hazards model. Results: Of the 1,500 sensitivity test performed at the Central Laboratory of Public Health of the state of Ceará, 266 revealed multidrug-resistant strains. Of those 266 patients, the authors were able to identify only 153, of whom 19 were excluded. Thus, our sampling consisted of 134 patients. Univariate analysis demonstrated that the significant factors associated with inadequate treatment were: noncompliance with the treatment, extreme poverty, drug intolerance, mistakes in the management of the patients, lack of medication being supplied by the health service, two or more previous treatments, pronounced lung cavities and bilateral lesions on chest X-rays. They found a further association (p < 0.0010) between alcoholism or smoking and noncompliance with the treatment. In the multivariate analysis, the factors associated with an outcome of inadequate treatment were: two or more previous treatments (p < 0.0001, OR = 5.9; CI 95%: 2.5-13.7), pronounced cavitation (p < 0.0217, OR = 2.7; CI 95%: 1.2-6.1) and bilateral chest X-ray lesions (p < 0.0226, OR = 3.2; CI 95%: 1.4-7.4) Conclusion: In the study, the authors observed that factors related to inadequate treatment are wide-ranging. An attempt at better control of the disease is warranted, especially in those patients with pronounced cavitation or bilateral lesions in chest X-rays. And those with 2 or more previous treatments.

Keywords: Tuberculosis, multidrug-resistant. Risk factors.

Multidrug resistant tuberculosis (MDR-TB) is a serious, feared, and difficult to control problem, and is showing a growing tendency worldwide. Objective: To make a risk factors analysis for acquired MDR-TB. Methods: A population-based case-control study was conducted in a retrospective way. Multidrug resistance was defined as resistance to at least Rifampin (RFM) + Isoniazid (INH), and susceptible TB was defined as the case that had had the first treatment in a period similar to the first treatment of the MDR-TB cases, but that was cured at the moment of the interview. The selection of cases was made based on the list of Susceptibility Tests (ST) carried out at the Central Laboratory of Public Health of the State of Ceará, in the period 1990 to 1999. The Proportion Method was used to make a survey of resistance to the six antituberculosis drugs (isoniazid, rifampin, pyrazinamide, ethambutol, ethionamide, streptomycin) that represent the standard treatment in Brazil. Controls were selected from the book of registry of TB cases. Univariate and multivariate analysis was performed and statistical significance was considered with a p value < 0.05. Results: Of the 1,500 ST performed in the period, 266 strains were multidrug resistant. Only 153 patients were identified. Of these, 19 were excluded. The Group of Cases comprised 134 patients and the Controls, 185. The following risk factors were found after the multivariate analysis: lack of sewer in the domicile, alcoholism + tobacco smoking, number of previous treatments, irregular treatments and lung cavities. Conclusion: Based on the evidence, conclusion is that these five factors play a role in the development of acquired MDR-TB, and that neutralizing such factors can contribute to the control of tuberculosis.