[Biostatistics: a fundamental tool for the elaboration of radiological articles]. / La bioestadística: una herramienta fundamental en la elaboración de artículos radiológicos.

Biostatistics has become an indispensable tool in all domains of the Health Sciences. Biostatistics is essential for ensuring valid decision making, and knowing the basic principles of biostatistics well will enable us to use this tool correctly. In this article, first biostatistics is defined and then its use and justification are discussed. The aim is to go through all of the steps that should be followed in the entire research process, beginning with specifying the objective of the study, approaching different study designs (cross-sectional, prospective and retrospective longitudinal, clinical trials) and the most commonly used statistical techniques in the Health Sciences, from descriptive statistics necessary to begin any study, to univariate analysis of both qualitative and quantitative variables, to the multivariate analyses most commonly used in our field.

La bioestadística: una herramienta fundamental en la elaboración de artículos radiológicos / Biostatistics: a fundamental tool for the elaboration of radiological articles

La bioestadística se ha convertido en una herramienta indispensable en todos los dominios de las Ciencias de la Salud, necesaria para tomar decisiones válidas, por lo que conocer bien sus principios básicos nos permitirá hacer un buen uso de ella. Tras definirla, se plantea el uso de su manejo y su justificación. Se pretende hacer un recorrido por las diferentes etapas que se deben seguir en todo proceso de investigación, empezando por concretar el objetivo del estudio, abordando los diversos diseños de estudios (transversales, longitudinales prospectivos y retrospectivos, ensayos clínicos) y las técnicas estadísticas más usualmente utilizadas en el ámbito de la salud, desde la estadística descriptiva para iniciar todo estudio, pasando por los análisis univariados tanto de variables cualitativas como cuantitativas, así como los análisis multivariados más utilizados en nuestro medio

Biostatistics has become an indispensable tool in all domains of the Health Sciences. Biostatistics is essential for ensuring valid decision making, and knowing the basic principles of biostatistics well will enable us to use this tool correctly. In this article, first biostatistics is defined and then its use and justification are discussed. The aim is to go through all of the steps that should be followed in the entire research process, beginning with specifying the objective of the study, approaching different study designs (cross-sectional, prospective and retrospective longitudinal, clinical trials) and the most commonly used statistical techniques in the Health Sciences, from descriptive statistics necessary to begin any study, to univariate analysis of both qualitative and quantitative variables, to the multivariate analyses most commonly used in our field

The changing pattern of tuberculosis and HIV co-infection in immigrants and Spaniards in the last 20 years.

OBJECTIVES: To evaluate the impact of immigration on tuberculosis (TB)-HIV co-infection in Spain in a prospective cohort of HIV patients. METHODS: Among 7761 HIV patients, we evaluated 1284 with at least one episode of TB between 1987 and 2006. Variables were compared between immigrants and Spaniards. RESULTS: Incidence of TB decreased from 20 to five cases per 100 patient-years in 2006 (P<0.01) and was always higher in immigrants than in Spaniards. The proportion of immigrants increased, reaching almost 50% of both new cases of HIV and TB-HIV co-infection in 2006. In 34.4% of patients, TB and HIV infection were diagnosed within the same year; simultaneous diagnosis was more frequent in immigrants (83.3%vs. 16.7%, P<0.001). Mortality was associated independently with age [hazard ratio (HR) 1.03, 95% confidence interval (CI) 1.01-1.05], TB diagnosis before 1996 (HR 2.6, 95% CI 1.8-3.6), use of highly active antiretroviral treatment (HR 0.494, 95% CI 0.37-0.66) and CD4 cell count at TB diagnosis (HR 0.996, 95% CI 0.995-0.997). CONCLUSIONS: Immigrants have a major impact on the incidence of TB in HIV patients, slowing down the decreasing trend in Spain. Simultaneous diagnosis of the co-infection in immigrants reveals a need to intensify HIV case finding in immigrants in Spain.

Economic evaluation of assistance to HIV patients in a Spanish hospital.

BACKGROUND: Little is known about the global effects of HAART on the use of medical resources after the complete implementation of this therapy in Spain. This study was designed to determine the use of medical resources and the costs of health care for HIV-infected patients. METHODS: All patients with HIV infection who came to our institution during the year 2002 were included in the study. We analyzed the global assistance data and pharmaceutical costs during the year. Costs were calculated based on a unitary cost for DRG and an officially assigned standard cost for outpatient clinic, visits to the day care unit and to the emergency room (ER), outpatient surgery, and total costs of pharmacy. RESULTS: The total cost for HIV-related health care assistance was euro739,048. The cost related to admissions was euro150,766.60; euro8631 per first visit and euro49,199.40 per successive visit; euro5085.10 per day care unit; euro14,920 per outpatient surgery; euro7655.70 per ER visit; and euro491,342.40 per antiretroviral treatment. A significant proportion of the total outpatient assistance was given by physicians other than HIV specialists, namely, 63% of the costs attributed to the first visit and 41% per successive visit. CONCLUSION: More than 50% of the costs of caring for HIV-infected patients are still attributed to antiretroviral therapy. Specialists other than infectious disease specialists provide a significant proportion of outpatient assistance. A method to control HIV costs is greatly needed.

Extra-laryngeal head and neck tuberculosis.

OBJECTIVE: Extra-laryngeal head and neck tuberculosis is exceptional. Therefore, a retrospective multicenter study in patients with head and neck tuberculosis, excluding solitary lymphadenitis and laryngeal locations was carried out. METHODS: We reviewed the patients with these features and tuberculosis confirmation by culture and/or histologic granuloma with presence of acid-fast bacilli (AFB). RESULTS: We found 16 patients with the following locations: eight in oral cavity and/or pharynx, four in ear, two in salivary glands, one in nose and one in frontal sinuses. The average duration of symptoms was 11.5 months. Purified protein derivative (PPD) was positive (> 10 mm) in all but one patient in whom it was performed (six of seven). Except tuberculous otitis, which occured without reactive lymphadenitis, this was present in 50% of the rest (six of the 12). In all cases a biopsy was required for diagnosis. Only in four patients, all with pharyngeal locations, was coincident pulmonary tuberculosis confirmed. One patient with tuberculous otitis developed meningitis and died; three additional patients (two with otitis) were cured but with sequelae; the evolution of the remaining patients was satisfactory with medical therapy. CONCLUSIONS: Extra-laryngeal head and neck tuberculosis has a slow course. The diagnosis is difficult due to the common absence of lung involvement and the usual requirements for biopsy procedures. The outcome is usually favorable with antituberculous drugs alone although in tuberculous otitis there are possibilities of complications.