Diagnóstico de proliferación bacteriana intestinal en niños: evidencia experimental para sustentar el empleo de lactulosa en la prueba de hidrógeno y su validación como prueba tamiz / Diagnosis of small intestinal bacterial overgrowth in children: the use of lactulose in the breath hydrogen test as a screening test

Introducción. Un recuento superior a 105 unidades formadoras de colonias por ml de aspirado duodenal se considera la “prueba de referencia” para el diagnóstico de proliferación bacteriana intestinal, a pesar de su caracter invasivo. La prueba de hidrógeno en el aliento, con lactulosa, se aplica como alternativa diagnóstica no invasiva, pero el fundamento para el empleo de lactulosa carece de solidez. Objetivos. Aportar evidencia experimental para sustentar el uso de lactulosa en la prueba de hidrógeno y validarla frente al cultivo de aspirado duodenal. Materiales y métodos. Para fundamentar el uso de lactulosa se comparó la cinética de la lactasa intestinal frente a lactulosa con su cinética frente a la lactosa. Con el fin de validar la prueba de hidrógeno, ésta se aplicó a 47 niños afectados por trastornos gastrointestinales y los resultados se compararon con los de la prueba de referencia. Mediante una tabla de contingencia se estimó la validez y con el índice kappa, la concordancia. Resultados. La cinética mostró que la lactasa es 240 veces menos eficiente que la lactulosa. La sensibilidad de la prueba de hidrógeno fue de 85,7 por ciento (82,0 por ciento-89,4 por ciento), la especificidad de 90,9 por ciento (89,3 por ciento-92,5 por ciento), el valor diagnóstico positivo de 80 por ciento (76,5 por ciento-83,5 por ciento) y el valor diagnóstico negativo de 93,8 por ciento (92,1 por ciento-95,4 por ciento). El índice kappa de 0,785 (0,54-0,95) indicó una importante concordancia entre las pruebas diagnósticas. Conclusiones. Se aporta evidencia experimental para sustentar el uso de la lactulosa en la prueba de hidrógeno y se valida ésta frente al patrón de referencia como prueba tamiz para diagnosticar la proliferación bacteriana intestinal.

Introduction.The standard method for diagnosis of small intestinal bacterial overgrowth is a duodenal aspirate that produces a coliform count greater than 105 colonic forming units/ml. Because this is an invasive procedure, the lactulose breath hydrogen test is considered as a non-invasive alternative. Better experimental support is required, however, for the routine use of lactulose in diagnosis. Objective. Experimental evidence is provided to support the use of lactulose in the breath hydrogen test. Validation of the test is accomplished by comparison to the duodenal aspirate culture. Materials and methods. A rational basis for the use of lactulose was established by a comparison of the kinetics of lactulose and lactose on intestinal lactase. For validation, the hydrogen test was applied to 47 children suffering from gastrointestinal disorders, and the results compared with aspirate culture counts. The validity of the hydrogen test was assessed by a contingency table and the degree of agreement established by the kappa index. Results. The kinetics data showed that lactase is 240 times less efficient in presence of lactulose than it is in presence of lactose. The sensitivity of the breath hydrogen test was 85.7% (82.0- 89.4%), its specificity 90.9% (89.3-92.5%), the predictive positive value 80.0% (76.5-83.5%) and the predictive negative value 93.8% (92.1-95.4%); the kappa index=0.785 (0.54-0.95) showed excellent agreement between the two diagnostic tests. Conclusion. The results provided experimental support for the use of lactulose in the breath hydrogen test, and it was validated as screening test in the diagnosis of small intestinal bacterial overgrowth.

[Diagnosis of small intestinal bacterial overgrowth in children: the use of lactulose in the breath hydrogen test as a screening test]. / Diagnóstico de proliferación bacteriana intestinal en niños: evidencia experimental para sustentar el empleo de lactulosa en la prueba de hidrógeno y su validación como prueba tamiz.

INTRODUCTION: The standard method for diagnosis of small intestinal bacterial overgrowth is a duodenal aspirate that produces a coliform count greater than 10(5) colonic forming units/ml. Because this is an invasive procedure, the lactulose breath hydrogen test is considered as a non-invasive alternative. Better experimental support is required, however, for the routine use of lactulose in diagnosis. OBJECTIVE: Experimental evidence is provided to support the use of lactulose in the breath hydrogen test. Validation of the test is accomplished by comparison to the duodenal aspirate culture. MATERIALS AND METHODS: A rational basis for the use of lactulose was established by a comparison of the kinetics of lactulose and lactose on intestinal lactase. For validation, the hydrogen test was applied to 47 children suffering from gastrointestinal disorders, and the results compared with aspirate culture counts. The validity of the hydrogen test was assessed by a contingency table and the degree of agreement established by the kappa index. RESULTS: The kinetics data showed that lactase is 240 times less efficient in presence of lactulose than it is in presence of lactose. The sensitivity of the breath hydrogen test was 85.7% (82.0-89.4%), its specificity 90.9% (89.3-92.5%), the predictive positive value 80.0% (76.5-83.5%) and the predictive negative value 93.8% (92.1-95.4%); the kappa index=0.785 (0.54-0.95) showed excellent agreement between the two diagnostic tests. CONCLUSION: The results provided experimental support for the use of lactulose in the breath hydrogen test, and it was validated as screening test in the diagnosis of small intestinal bacterial overgrowth.

Factors affecting patient adherence to highly active antiretroviral therapy.

OBJECTIVE: To determine the clinical and demographic variables related to adherence to highly active antiretroviral therapy (HAART) in patients treated in our hospital and identify the characteristics of nonadherent patients. METHODS: Outpatients receiving treatment with HAART (n = 283) were asked about variables related to adherence and to complete the APGAR (family support), State-Trait Anxiety questionnaire (STAI) (emotional situation), and IAS (social support) questionnaires. Patients were classified in 2 groups depending on whether adherence was > or =95% or <95%. Adherence was defined as the percentage of dosage forms prescribed that were obtained by the patient at the hospital pharmacy. A multivariate analysis was created to analyze how each significant variable affected adherence. RESULTS: Our data showed significant nonadherence for patients with the following factors: low level of education, unemployed, emotional situation, and abuse of substances including intravenous drugs. All significant variables were included in a logistic regression model to optimize the results. This model considered 4 variables: age (95% CI 0.89 to 0.99), number of antiretroviral drugs (95% CI 1.05 to 2.11), STAI Anxiety/Trait test (95% CI 2.02 to 6.02), and abuse of drugs (95% CI 1.20 to 3.95). CONCLUSIONS: We recommended special intervention to reinforce adherence for younger patients, patients taking a high number of antiretroviral drugs, those who have a history of intravenous drug use, and those with high anxiety status.