Cribado de la tuberculosis en inmigrantes adolescentes indocumentados usando el QuantiFERON ®-TB Gold In-Tube / Tuberculosis screening program for undocumented immigrant teenagers using the QuantiFERON ®-TB Gold In-Tube test

Fundamento y objetivo: El objetivo de este estudio fue conocer la prevalencia de la infección tuberculosa en inmigrantes adolescentes indocumentados utilizando una estrategia con la prueba de la tuberculina (PT) para el cribado inicial y el QuantiFERON®-TB Gold In-Tube (QFT-GIT) como prueba confirmativa. Pacientes y método: Se incluyeron inmigrantes adolescentes recién llegados a 2 centros de alojamiento del País Vasco (España) entre los años 2007 y 2012. La PT se aplicó en todos los participantes, y el QFT-GIT, selectivamente en los reactores con una PT ≥ 5 mm. Resultados: Completaron el estudio 845 inmigrantes, mayoritariamente africanos (99,5%). Un 51% de los inmigrantes con una PT ≥ 5 mm fue QFT-GIT positivo, que corresponde el 17% de toda la muestra. Se encontraron 2 casos con tuberculosis activa (2/845: 0,24%). La concordancia entre la PT (≥ 10 mm) y el QFT-GIT fue del 63%, con un 57% de resultados concordantes positivos y un 96% de concordantes negativos. Hubo 246 casos con PT ≥ 10 mm (29%), con diferencias significativas entre magrebíes (21,5%) y subsaharianos (67%) (p < 0,001). La vacunación con el bacilo Calmette-Guérin fue un predictor independiente de tener una PT ≥ 10 mm (odds ratio [OR] 2,11, p < 0,001) y de la discordancia PT+/QFT-GIT−, tanto para una PT ≥ 5 como para una PT ≥ 10 mm (OR 2,16, intervalo de confianza del 95% [IC 95%] 1,46-3,20, y OR 1,91, IC 95% 1,23-2,97, respectivamente). La proporción de QFT-GIT positivo aumentó significativamente con el incremento de la positividad de la PT, con asociación positiva en todos los tramos analizados: 10-14 mm (OR 7,95, IC 95% 1,79-35,33), 15-19 mm (OR 35, IC 95% 7,93-154,52) y ≥ 20 mm (OR 91,3, IC 95% 18,20-458,11). Conclusión: La alta prevalencia de infección tuberculosa latente en los inmigrantes de origen subsahariano hace recomendable la implementación de programas de cribado en esta población. Utilizando el QFT-GIT se redujo en un 43% el número de candidatos a la quimioprofilaxis con arreglo a la PT (≥ 10 mm) (AU)

Background and objective: The aim of this study was to determine the prevalence of tuberculosis infection in undocumented immigrant teenagers using a tuberculin skin test (TST) for initial screening and cuantiFERON®-TB Gold In-Tube (QFT-GIT) as a confirmatory test. Patient and method: From 2007 to 2012, under 19 year-old immigrant teenagers from 2 accommodation centers of the Basque Country (Spain) were included in the study. The TST was done in all of them and the QFT-GIT was done in selected patients with a TST ≥ 5 mm. Results: Eight hundred and forty-five immigrants were included, most of them from Africa (99.5%). Fifty-one percent of immigrants with TST ≥ 5 mm has a positive QFT-GIT. We found 2 cases of active tuberculosis (2/845: 0.24%). The concordance between TST (≥ 10 mm) and QFT-GIT was 63%, with 57% of positive concordance cases and 96% of negative concordances. There were 246 cases with TST ≥ 10 mm (29%), with significant differences between Magrebis (21.5%) and Subsaharians (67%) (P < .001). Vaccination with Calmette-Guéin bacille was an independent predictor for having a TST ≥ 10 mm (OR: 2.11; P < .001) and for the discordance TST+/QFT-GIT−, both for a TST ≥ 5 and a TST ≥ 10 mm (OR 2.16, 95% confidence interval [95% CI] 1.46-3.20, and OR 1.91 95% CI 1.23-2.97, respectively). The positive value of QFT-GIT increased significantly as the TST increased, with a positive association in all the cut-off points analyzed: 10-14 mm (OR 7.95, 95% CI 1.79-35.33), 15-19 mm (OR 35, 95% CI 7.93-154.52) and ≥ 20 mm (OR 91.3, 95% CI 18.20-458.11). Conclusion: Due to the high prevalence of latent tuberculosis infection in Subsaharian immigrants, we recommend implementing screening programs in this population. Using QFT-GIT, the number of candidates for chemoprophylaxis was reduced to 43% compared with TST alone (≥ 10 mm) (AU)

[Tuberculosis screening program for undocumented immigrant teenagers using the QuantiFERON(®)-TB Gold In-Tube test]. / Cribado de la tuberculosis en inmigrantes adolescentes indocumentados usando el QuantiFERON(®)-TB Gold In-Tube.

BACKGROUND AND OBJECTIVE: The aim of this study was to determine the prevalence of tuberculosis infection in undocumented immigrant teenagers using a tuberculin skin test (TST) for initial screening and QuantiFERON(®)-TB Gold In-Tube (QFT-GIT) as a confirmatory test. PATIENT AND METHOD: From 2007 to 2012, under 19 year-old immigrant teenagers from 2 accommodation centers of the Basque Country (Spain) were included in the study. The TST was done in all of them and the QFT-GIT was done in selected patients with a TST≥5mm. RESULTS: Eight hundred and forty-five immigrants were included, most of them from Africa (99.5%). Fifty-one percent of immigrants with TST ≥ 5 mm has a positive QFT-GIT. We found 2 cases of active tuberculosis (2/845: 0.24%). The concordance between TST (≥ 10 mm) and QFT-GIT was 63%, with 57% of positive concordance cases and 96% of negative concordances. There were 246 cases with TST ≥ 10 mm (29%), with significant differences between Magrebis (21.5%) and Subsaharians (67%) (P<.001). Vaccination with Calmette-Guéin bacille was an independent predictor for having a TST ≥ 10 mm (OR: 2.11; P<.001) and for the discordance TST+/QFT-GIT-, both for a TST≥5 and a TST≥10mm (OR 2.16, 95% confidence interval [95% CI] 1.46-3.20, and OR 1.91 95% CI 1.23-2.97, respectively). The positive value of QFT-GIT increased significantly as the TST increased, with a positive association in all the cut-off points analyzed: 10-14 mm (OR 7.95, 95% CI 1.79-35.33), 15-19 mm (OR 35, 95% CI 7.93-154.52) and ≥ 20 mm (OR 91.3, 95% CI 18.20-458.11). CONCLUSION: Due to the high prevalence of latent tuberculosis infection in Subsaharian immigrants, we recommend implementing screening programs in this population. Using QFT-GIT, the number of candidates for chemoprophylaxis was reduced to 43% compared with TST alone (≥ 10 mm).

Etiology of community-acquired pneumonia in a population-based study: link between etiology and patients characteristics, process-of-care, clinical evolution and outcomes.

BACKGROUND: The etiologic profile of community-acquired pneumonia (CAP) for each age group could be similar among inpatients and outpatients. This fact brings up the link between etiology of CAP and its clinical evolution and outcome. Furthermore, the majority of pneumonia etiologic studies are based on hospitalized patients, whereas there have been no recent population-based studies encompassing both inpatients and outpatients. METHODS: To evaluate the etiology of CAP, and the relationship among the different pathogens of CAP to patients characteristics, process-of-care, clinical evolution and outcomes, a prospective population-based study was conducted in Spain from April 1, 2006, to June 30, 2007. Patients (age >18) with CAP were identified through the family physicians and the hospital area. RESULTS: A total of 700 patients with etiologic evaluation were included: 276 hospitalized and 424 ambulatory patients. We were able to define the aetiology of pneumonia in 55.7% (390/700). The most frequently isolated organism was S. pneumoniae (170/390, 43.6%), followed by C. burnetti (72/390, 18.5%), M. pneumoniae (62/390, 15.9%), virus as a group (56/390, 14.4%), Chlamydia species (39/390, 106%), and L. pneumophila (17/390, 4.4%). The atypical pathogens and the S. pneumoniae are present in pneumonias of a wide spectrum of severity and age. Patients infected by conventional bacteria were elderly, had a greater hospitalization rate, and higher mortality within 30 days. CONCLUSIONS: Our study provides information about the etiology of CAP in the general population. The microbiology of CAP remains stable: infections by conventional bacteria result in higher severity, and the S. pneumoniae remains the most important pathogen. However, atypical pathogens could also infect patients in a wide spectrum of severity and age.

Prevalencia de silicosis en una marmolería tras la exposición a conglomerados de cuarzo / Prevalence of silicosis in a marble factory after exposure to quartz conglomerates

En esta nota mostramos la elevada prevalencia de silicosis encontrada en una marmolería tras una exposición a una novedosa presentación de sílice.Se trata de un estudio observacional, prospectivo, en el que se han estudiado 11 trabajadores que se exponen desde 1995 a diversas presentaciones de superficies de cuarzo. Los puestos de trabajo se dividen en dos grupos: por una parte 4 sujetos desarrollan trabajos de corte en el taller; el resto de los trabajadores trabaja en el montaje. Hasta la fecha no han utilizado sistemas de protección respiratoria específicos.Se han diagnosticado 6 casos de silicosis, lo que supone una prevalencia de enfermedad para este ámbito del 54,5%. De los 6 afectados, 5 (83,33%) son montadores.Destacamos el elevado riesgo de desarrollo de silicosis en el manejo de los diversos productos que conforman la gama de superficies de cuarzo(AU)

In this note we present the increased prevalence of silicosis found in a marble factory after exposure to a new presentation of silica.A prospective, observational study was conducted on 11 workers who were exposed to different presentations of quartz surfaces since 1995. The jobs were divided into two groups: 4 subjects worked in the cutting workshop; the rest of the workers worked in assembly. Up to that date they had not used any specific respiratory protection apparatus.Six cases of silicosis have been diagnosed, which assumes a disease prevalence in this environment of 54.5%. Of the 6 affected, 5 (83.3% are assemblers.We highlight the high risk of developing silicosis in the handling of different products which make up the range of quartz surfaces(AU)

Prevalence of silicosis in a marble factory after exposure to quartz conglomerates.

In this note we present the increased prevalence of silicosis found in a marble factory after exposure to a new presentation of silica. A prospective, observational study was conducted on 11 workers who were exposed to different presentations of quartz surfaces since 1995. The jobs were divided into two groups: 4 subjects worked in the cutting workshop; the rest of the workers worked in assembly. Up to that date they had not used any specific respiratory protection apparatus. Six cases of silicosis have been diagnosed, which assumes a disease prevalence in this environment of 54.5%. Of the 6 affected, 5 (83.3% are assemblers. We highlight the high risk of developing silicosis in the handling of different products which make up the range of quartz surfaces.

Pauta de tres meses de rifampicina e isoniacida para el tratamiento de la infección latente tuberculosa / Three-month course of rifampicin and isoniazid for the treatment of latent tuberculous infection

Fundamento y objetivos: La isoniacida (H) es la medicación de referencia utilizada para el tratamiento de la infección latente tuberculosa (ILT). La duración del tratamiento con H y su hepatotoxicidad suponen un serio obstáculo para su cumplimentación. En distintas guías clínicas se recomienda la pauta de 3 meses con rifampicina (R) e H como una alternativa aceptable a la de 6–9 meses con H. En el presente estudio presentamos nuestra experiencia con esta nueva pauta. Pacientes y método: A partir del año 2001 se empezó a ofertar la pauta de 3RH a los individuos mayores de 14 años, reclutados en el estudio de contactos. Se consideró buena adherencia cuando el paciente así lo manifestó y acudió a los controles mensuales programados. Se realizaron análisis hepáticos basales en aquellos pacientes que tenían riesgo de hepatotoxicidad y en todos los pacientes mayores de 35 años. En todos los casos se realizó un control hepático al primer mes de tratamiento y en cuanto presentaron síntomas de intolerancia. Se cruzaron las bases de datos de contactos y casos de tuberculosis para estimar el número de individuos que enfermaron de tuberculosis. Resultados: Entre los años 2000–2008 se indicó tratamiento para la ILT en 547 contactos. El 7,8% rechaza el tratamiento, el 34,1% con la pauta de 6H, el 63,5% con la pauta de 3RH y el 2,3% a otras pautas. Un total de 84,97% (147/173) de los pacientes con la pauta de 6H y un 92,55% (302/322) con la pauta de 3RH completaron el tratamiento (p=0,024). Abandonaron por hepatotoxicidad el 2,37% (4/169) y el 1,6% (5/313) de los pacientes con pauta de 6H y 2RH, respectivamente (p=0,33). No hubo enfermos entre los pacientes que completaron el tratamiento en ninguna de las 2 pautas de estudio. Conclusión: Hubo una mayor adherencia (estadísticamente significativa) y menor hepatotoxicidad con la pauta de 3RH. Ambas pautas demostraron una total efectividad (AU)

Background and objectives: Isoniazid (I) is the drug of choice for treating latent tuberculous infection (LTI). Duration of treatment with I and its liver toxicity represent a serious drawback for a correct enforceability. In several clinical guides, a 3-month course with rifampicin (Rif) and I is recommended as an acceptable alternative to the 6–9 month course with I. Here we present our experience with this new regimen.Patients and methods: From 2001, the 3-month regimenm with Rif and I was offered to patients older than 14 years, who were recruited in the contacts study. A good adherence was considered when the patient manifested so and he/she went to the scheduled monthly controls. We performed baseline liver analyses in those patients at risk of hepatotoxicity and in all patients older than 35 years. In all cases, a liver laboratory control was done at the first month of treatment and whenever patients had symptoms suggestive of intolerance. Databases of tuberculosis controls and contacts were crossed to evaluate the number of individuals who developed tuberculosis.Results: Between 2000 and 2008, treatment for LTI was indicated in 547 contacts (7.8% refused treatment, 34.1% with the 6-month I course, 63.5% with the 3-month Rif and I course and 2.3% with other regimens). A total of 84.97% (147/173) patients with the 6-month I regimen and 92.55% (302/322) with the 3-month Rif and I course fulfilled the treatment (p=0,024). 2.37% (4/169) and 1.6% (5/313) patients with the 6-month I course and 3-month Rif and I course, respectively, withdrew because of hepatotoxicity (p=0,33). There were no patients among those who fulfilled the treatment in any of the 2 study arms.Conclusion: There was a higher adherence (statistically significant) and lower hepatotoxicity with the 3-month Rif and I regimen. Both regimens showed a full effectivity (AU)

[Three-month course of rifampicin and isoniazid for the treatment of latent tuberculous infection]. / Pauta de tres meses de rifampicina e isoniacida para el tratamiento de la infección latente tuberculosa.

BACKGROUND AND OBJECTIVES: Isoniazid (I) is the drug of choice for treating latent tuberculous infection (LTI). Duration of treatment with I and its liver toxicity represent a serious drawback for a correct enforceability. In several clinical guides, a 3-month course with rifampicin (Rif) and I is recommended as an acceptable alternative to the 6-9 month course with I. Here we present our experience with this new regimen. PATIENTS AND METHODS: From 2001, the 3-month regimen with Rif and I was offered to patients older than 14 years, who were recruited in the contacts study. A good adherence was considered when the patient manifested so and he/she went to the scheduled monthly controls. We performed baseline liver analyses in those patients at risk of hepatotoxicity and in all patients older than 35 years. In all cases, a liver laboratory control was done at the first month of treatment and whenever patients had symptoms suggestive of intolerance. Databases of tuberculosis controls and contacts were crossed to evaluate the number of individuals who developed tuberculosis. RESULTS: Between 2000 and 2008, treatment for LTI was indicated in 547 contacts (7.8% refused treatment, 34.1% with the 6-month I course, 63.5% with the 3-month Rif and I course and 2.3% with other regimens). A total of 84.97% (147/173) patients with the 6-month I regimen and 92.55% (302/322) with the 3-month Rif and I course fulfilled the treatment (p=0.024). 2.37% (4/169) and 1.6% (5/313) patients with the 6-month I course and 3-month Rif and I course, respectively, withdrew because of hepatotoxicity (p=0.33). There were no patients among those who fulfilled the treatment in any of the 2 study arms. CONCLUSION: There was a higher adherence (statistically significant) and lower hepatotoxicity with the 3-month Rif and I regimen. Both regimens showed a full effectivity.

Study of community-acquired pneumonia: incidence, patterns of care, and outcomes in primary and hospital care.

BACKGROUND: To asses the incidence, patterns of care, and outcomes of community-acquired pneumonia (CAP) in the population of a defined geographic area. METHODS: Prospective study conducted from April 1, 2006, to June 30, 2007. All adult patients (age ≥18) with CAP in the Comarca Interior region of northern Spain were identified through the region's 150 family physicians and the emergency department (ED) of the area's general teaching hospital. RESULTS: During a 15-month period, 960 patients with CAP were identified: 418 hospitalized and 542 ambulatory patients. The hospitalization rate was 43.5% and the global 30-day mortality was 4% (38 patients). Of the patients treated at home, most (90.4%) had mild pneumonia, only 3.1% (17 patients) were subsequently hospitalized, with a 30-day mortality rate of 0%. However, 48.9% were not treated according to antibiotic recommendations of the Spanish Society of Pneumology. Mean duration of return to daily activity was 18.8 days for the entire population. The incidence study was restricted to the first 12 months, during which 787 patients fulfilled the inclusion criteria. This represented an incidence of pneumonia of 3.1/1000 adults per year. Both the incidence of CAP and hospitalization for it rose with age. CONCLUSIONS: Our study offers information about CAP in the general population and provides feedback for the management of CAP. Although the selection of patients to be treated at home was appropriate, the choice of empiric antibiotic therapy for ambulatory CAP was problematic.

Cuidados respiratorios intermedios: un año de experiencia / A Year's Experience in an Intermediate Respiratory Care Unit

IntroducciónEl objetivo del presente estudio es describir las características y resultados de los pacientes ingresados en una unidad de cuidados respiratorios intermedios (UCRI).Pacientes y métodosSe ha realizado un estudio prospectivo y observacional de un año de duración, en el que se estudió a todos los pacientes ingresados en nuestra UCRI durante ese período. Se analizaron variables sociodemográficas, clínicas, escala APACHE-II, evolución gasométrica, duración de la estancia hospitalaria, mortalidad y reingreso hospitalario.ResultadosEvaluamos a 190 pacientes (un 64,2% varones), con una edad media de 69,4 años. El 43,2% tenía un índice de Charlson mayor de 2. El APACHE-II fue de 16,3 en el Servicio de Urgencias y de 14,3 al entrar en la UCRI. El 50% de los pacientes ingresó para recibir ventilación, y de ellos sólo 6 (5,7%) ingresaron para la desconexión del ventilador. La duración media de la estancia en la UCRI fue de 3,7 días. La tasa de reingresos fue del 12,7%. La mortalidad fue del 12,6% durante el episodio de hospitalización, y del 11,6% a los 90 días del alta.ConclusionesLos ingresados en nuestra UCRI son pacientes mayores, con importante comorbilidad y mortalidad elevada, tanto durante el episodio de hospitalización como a los 90 días del alta hospitalaria. No hemos encontrado diferencias estadísticamente significativas en los resultados (estancia media, reingresos, mortalidad) en función del tipo de cuidados (ventilación frente a seguimiento) administrados al paciente(AU)

BackgroundThe aim of this study was to describe the characteristics and results of patients admitted to an intermediate respiratory care unit (IRCU).Patients and MethodsWe performed a 12-month prospective observational study of all the patients admitted to our IRCU during the study period. We analyzed sociodemographic and clinical variables, the APACHE-II score, blood gas parameters, duration of stay in hospital, mortality, and readmission to hospital.ResultsWe evaluated 190 patients (64.2% men), with a mean age of 69.4 years. A score of greater than 2 on the Charlson index was recorded in 43.2% of patients. The mean APACHE-II score was 16.3 in the emergency department and 14.3 on entering the IRCU. Fifty percent of the patients were admitted to receive ventilation and, of these, only 6 (5.7%) were admitted for disconnection of the ventilator. The mean duration of stay in the IRCU was 3.7 days. The readmission rate was 12.7% Mortality was 12.6% during hospitalization and 11.6% 90 days after discharge.ConclusionsThe patients admitted to our IRCU were elderly, with considerable comorbidity and high mortality, both during hospitalization and 90 days after discharge from hospital. The results revealed no statistically significant differences (mean length of stay, readmission, mortality) according to the type of care administered to the patients (ventilation compared to monitoring(AU)

[A year's experience in an intermediate respiratory care unit]. / Cuidados respiratorios intermedios: un año de experiencia.

BACKGROUND: The aim of this study was to describe the characteristics and results of patients admitted to an intermediate respiratory care unit (IRCU). PATIENTS AND METHODS: We performed a 12-month prospective observational study of all the patients admitted to our IRCU during the study period. We analyzed sociodemographic and clinical variables, the APACHE-II score, blood gas parameters, duration of stay in hospital, mortality, and readmission to hospital. RESULTS: We evaluated 190 patients (64.2% men), with a mean age of 69.4 years. A score of greater than 2 on the Charlson index was recorded in 43.2% of patients. The mean APACHE-II score was 16.3 in the emergency department and 14.3 on entering the IRCU. Fifty percent of the patients were admitted to receive ventilation and, of these, only 6 (5.7%) were admitted for disconnection of the ventilator. The mean duration of stay in the IRCU was 3.7 days. The readmission rate was 12.7% Mortality was 12.6% during hospitalization and 11.6% 90 days after discharge. CONCLUSIONS: The patients admitted to our IRCU were elderly, with considerable comorbidity and high mortality, both during hospitalization and 90 days after discharge from hospital. The results revealed no statistically significant differences (mean length of stay, readmission, mortality) according to the type of care administered to the patients (ventilation compared to monitoring).

[Longitudinal incidence of tuberculosis in a cohort of contacts: factors associated with the disease]. / Incidencia longitudinal de la tuberculosis en una cohorte de contactos: factores asociados a la enfermedad.

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.

Incidencia longitudinal de la tuberculosis en una cohorte de contactos: factores asociados a la enfermedad / Longitudinal incidence of tuberculosis in a cohort of contacts: factors associated with the disease

Objetivo: Conocer la incidencia de tuberculosis (TB) en una cohorte de contactos y analizar las variables asociadas a la enfermedad. Métodos: Se ha efectuado un análisis prospectivo de los estudios de contactos (EC) realizados en un área sanitaria del País Vasco del 1 de enero de 1995 al 31 de diciembre de 2004. La variable dependiente fue el número de casos de TB detectados entre los contactos. Las variables independientes fueron la edad, el sexo, la prueba de la tuberculina (PT) y el grado de contacto, y en los casos índice, la localización de la TB y la baciloscopia del esputo. Resultados: De los 5.444 contactos de 596 pacientes con TB que se estudiaron, se encontraron 66 casos secundarios de TB (40 en el momento del EC y 26 en el período posterior), la mayoría de ellos (73%) durante el primer año. El análisis multivariante demostró una relación significativa entre la detección de casos secundarios y las siguientes variables: contacto íntimo (odds ratio [OR] = 3,05; intervalo de confianza [IC] del 95%, 1,75-5,31), baciloscopia positiva (OR = 8,54; IC del 95%, 2,06-35,43), PT de 10 mm o mayor (OR = 10,18; IC del 95%, 4,27-24,26) y edad inferior a 30 años (OR = 3,35; IC del 95%, 1,88-5,98). El modelo predictivo final que se obtuvo utilizando estas 3 variables alcanzó una sensibilidad del 77,4%, una especificidad del 80,3% y un área bajo la curva de 0,83 (IC del 95%, 0,78-0,88). Conclusiones: El EC es una estrategia válida para la detección de nuevos casos de TB. La intervención profiláctica debería realizarse de forma precoz y dirigirse prioritariamente a los contactos jóvenes de pacientes bacilíferos, utilizando como referencia una PT de 10 mm o mayor

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