Uso de Albendazol como tratamiento de la equinococcosis: toma de decisiones basadas en la validez interna y externa de un estudio concerniente / Internal and external validity of a clinical trial reporting the use of albendazole for the treatment of hydatidosis

Introducción: El tratamiento de la Equinoccocosis es quirúrgico. El estudio de Keshmiri plantea el uso de albendazol como alternativa. El objetivo de este estudio es determinar validez interna y externa del estudio de Keshmiri. Material y método: Se aplicaron 4 instrumentos que valoran diferentes ámbitos metodológicos al estudio de Keshmiri. Se realizó lectura crítica; se analizó calidad metodológica, validez interna y externa con 3 instrumentos: MINCIR, CONSORT y SIGN. Estos, fueron aplicados por 7 investigadores con formación en epidemiología clínica. Resultados: La guía de lectura permitió verificar carencia de objetivo específico, asignación aleatoria y enmascaramiento mal definido. Los pacientes no fueron considerados hasta el final del estudio (hubo pérdida de 22,7 por ciento de pacientes en la rama del fármaco y de 42,8 por ciento de pacientes en la rama placebo). La escala MINCIR permitió identificar un ensayo clínico, con enmascaramiento, secuencia de aleatorización no clara, sin cálculo del tamaño de la muestra y objetivos vagos. CONSORT permitió comprobar carencia de hipótesis de trabajo y objetivos específicos; no identificación de variable primaria y tamaño de muestra, ambigüedades del proceso de aleatorización, enmascaramiento poco claro, ausencia de ajuste estadístico y omisión de análisis de subgrupos. SIGN permitió objetivar los mismos problemas antes descritos. Conclusión: Los instrumentos aplicados, pusieron en evidencia falencias metodológicas que objetan la validez interna y externa del estudio. La adopción de este protocolo debe observarse con precaución.

Background: Classic treatment of echinococcosis is surgery. The study of Keshmiri raises the use of albendazole as an alternative. Aim: To determine internal and external validity of the Keshmiri study. Material and methods: Four instruments that assess methodological quality, were applied to the manuscript. A critical reading was done and the internal and external validity of the methodological quality was analyzed with three scales: Methodology and Research in Surgery (MINCIR), Consolidated Standards of Reporting Trials (CONSORT) and Scottish Intercollegiate Guidelines Network (SIGN). Guides and scales were applied by 7 researchers with training in clinical epidemiology. Results: The Keshmiri study has not a specific objective. The method used for random assignment is not described and not all patients were assessed at the end of the study due to a loss form follow up of 23 percent of patients in drug branch and 43 percent in the placebo branch. MINCIR scale identified a blinded randomized clinical trial, with an unclear randomized sequence, without sample size estimation and vague objectives. CONSORT proved the lack of working hypothesis and specific objectives as well as an absence of identification of the primary variable, absence of sample size calculation, ambiguities in the randomization process, absence of statistical adjustment and the omission of a subgroup analysis. SIGN verified the same methodological errors. Conclusions: The applied instruments found methodological deficiencies that jeopardize the internal and external validity of the study.

Aislamiento de bacterias periodontop ticas desde hemocultivos y ateromas obtenidos de pacientes con aterosclerosis y periodontitis / Isolation of periodontal bacteria from blood samples and atheromas in patients with atherosclerosis and periodontitis

Background: Periodontitis is a common oral disease produced by bacterial species that reside in the subgingival plaque. These microorganisms have been associated to atherosclerosis and it is suggested that periodontitis is a cardiovascular risk factor. Aim: To isolate periodontal bacteria from blood and atheroma samples, from patients with atherosclerosis and periodontitis. Material and methods: Twelve patients with periodontitis and a clinical diagnosis of atherosclerosis and 12 patients with periodontitis but without atherosclerosis were studied. Blood samples were obtained immediately before and after scaling and root planing. The samples were incubated in aerobic and anaerobic conditions. One week after scaling, atheromatous plaques were obtained during endarterectomy in the 12 patients with atherosclerosis. These were homogenized and cultured for aerobic and anaerobic bacteria. Microorganisms were identified by means ofPCR. Results: Five patients with and two without atherosclerosis, had bacteremia after scaling and root planing. Bacterial species isolated from blood samples were the same found in periodontic pockets. Four atheromatous plaques of patients with bacteremia yielded positive cultures. The isolated bacteria were the same found in blood samples and periodontal pockets. Conclusions: Bacteremia occurred in seven of 24 patients after scaling and root planing. In four patients, the same species found in periodontic pockets and blood cultures were detected in atherosclerotic plaques obtained one week after the dental procedure.