[Is chemoprophylaxis a good strategy for tuberculosis control?]

[Tuberculosis in a cohort of patients with systemic lupus erythematosus]

OBJECTIVES

1) To study tuberculosis (TB) infection in a cohort of patients with systemic lupus erythematosus (SLE) and to compare its frequency and characteristics with that of others series. 2) To look for differential characteristic among SLE patients with and without TB. 3) To investigate if there was any relationship between TB's most severe forms and higher doses of glucocorticoids (GC) or other immunosuppressants.

PATIENTS AND METHOD

Retrospective review of medical records of 789 SLE patients and description of the clinical characteristics of 13 cases of active TB infection among them. Bibliographical search in MEDLINE-PubMed of the SLE/TB series published, using the terms: infection, tuberculosis, systemic lupus erythematosus. Comparative study of clinical, biological and therapeutic differences between cases (SLE/TB+) and controls (SLE/TB) using χ(2) and Fisher exact test.

RESULTS

Thirteen patients with active tuberculosis were detected (10 women, average age 36 years/SD 11,2/prevalence 1,6%). Nine (69,2%) of them were primary infections and 4 (30,8%) reactivations. Microbiological diagnosis (smear examination for acid-fast bacilli and/or culture on Lowestein-Jensen medium) was established in 11 patients (84,6%). TB Pulmonary manifestations was present in 9 patients (69,2%) and extra-pulmonary manifestations were found in 8 [(61,5%); 6 of them (46%) were disseminated forms]. Nine (69,2%) patients were on GC therapy at the moment TB was diagnosed. Four of the TB patients died (30,8%). Myositis was more frequent in TB cases (p < 0,05). This data is similar to that reported in the literature.

CONCLUSIONS

In our series, TB mortality was high (30,8%) in a patients with SLE. Frequency of extrapulmonary forms was double than that described in the Spanish population. Patients with higher GC dose had more severe forms of TB.

[Longitudinal incidence of tuberculosis in a cohort of contacts: factors associated with the disease]

OBJECTIVE

To investigate the incidence of tuberculosis (TB) in a cohort of contacts and to analyze the variables associated with the disease.

METHODS

A prospective analysis was undertaken of all the contact investigations carried out in a health district in the Basque Country in northern Spain between January 1, 1995 and December 31, 2004. The dependent variable was the number of cases of TB detected among the contacts. Independent variables were age, sex, tuberculin skin test result, and the degree of contact. In index cases, additional variables were the site of the disease and smear test result.

RESULTS

Analysis of 5444 contacts of 596 patients with TB yielded 66 secondary cases of TB (40 at the time of the contact investigation and 26 at a later stage); the majority (73%) developed the disease within 12 months. Multivariate analysis revealed a significant relationship between the detection of secondary cases and the following variables: close contact (odds ratio [OR], 3.05; 95% confidence interval [CI], 1.75-5.31), positive smear test (OR, 8.54; 95% CI, 2.06-35.43), induration of 10 mm or larger (OR, 10.18; 95% CI, 4.27-24.26), and age under 30 years (OR, 3.35; 95% CI, 1.88-5.98). The final predictive model constructed on the basis of these 3 variables had a sensitivity of 77.4%, a specificity of 80.3%, and an area under the curve of 0.83 (95% CI, 0.78-0.88).

CONCLUSIONS

The contact investigation is a valid strategy for the detection of new cases of TB. Prophylactic treatment should be implemented at an early stage and priority should be given to young contacts of smear positive patients using an induration size of 10 mm or more as a reference.

Factores asociados a la infección tuberculosa latente en los contactos de pacientes afectados

BACKGROUND

As tuberculosis control programs have reached acceptable levels in the identification and treatment of persons with active tuberculosis, the next step should be to develop methods of preventing new cases. Persons with latent tuberculosis infection (LTI) are considered to have a higher risk of developing active tuberculosis. The objective of this study was to evaluate the prevalence of LTI and its associated factors in the contacts of tuberculosis patients.

METHODS

We studied the contacts of tuberculosis patients who were examined in the Center for Tuberculosis Control and Prevention in Lleida (Spain) from 1991-1997. Factors associated with the index case (demographic, radiographic, bacteriologic and therapeutic) and tuberculin skin test results and demographic data in contacts were collected. Data on HIV infection, injection drug use and alcohol consumption in tuberculosis patients were also collected. The associations were assessed by obtaining crude and adjusted odds ratios.

RESULTS

The prevalence of LTI among contacts was 36.1% (780/2,161). In the multivariate analysis a higher frequency of LTI was detected in contacts older than 14 years (ORa = 3.34; 95% CI, 2.51-4.45), contacts who had a higher degree of exposure to the index case (ORa = 1.96; 95% CI, 1.59-2.42), contacts of pulmonary tuberculosis patients (ORa = 1.54; 95% CI, 1.01-2.35), contacts of patients with a positive sputum smear (ORa = 1.51; 95% CI, 1.15-1.99), contacts of patients with caverns on chest x-ray (ORa = 1.27; 95% CI, 1.01-1.61) and contacts of patients with delayed treatment (ORa = 1.31; 95% CI, 1.05-1.62).

CONCLUSIONS

The overall prevalence of LTI in the contacts of patients with tuberculosis was high. Among the factors studied, delayed treatment in the index case was independently associated with the frequency of LTI in tuberculosis contacts. Measures for the early diagnosis and treatment of tuberculosis should be intensified.

Isoniazid hepatotoxicity among drug users: the role of hepatitis C

The incidence of and risk factors associated with hepatotoxicity in patients with chronic hepatitis have not been systematically studied. Therefore, we conducted a prospective study that included former drug users who were treated with isoniazid for latent tuberculosis infection. Of 415 patients, 20 (4.8%; 95% confidence interval [CI], 3-7.4) had hepatotoxicity diagnosed, and 6 (1.4%; 95% CI, 0.5-3.2) developed clinical hepatitis, none of whom had serious symptoms. The only 2 factors independently associated with isoniazid hepatotoxicity were excessive alcohol consumption (odds ratio [OR]; 4.2, 95% CI, 1.6-10.8; P=.002) and a high baseline alanine transaminase level (OR, 4.3; 95% CI, 1.6-11.4; P=.002). The presence of hepatitis C virus antibodies was associated with hepatotoxicity only on univariate analysis. Treatment with isoniazid in drug users appears to be safe and well tolerated, although frequent asymptomatic elevations in transaminase levels were observed.