Progression of null or mild lower urinary tract symptoms indicative of benign prostatic hyperplasia after 2 years of follow-up in non-treated men aged 40 years or older.

OBJECTIVES: After screening men aged 40 years or older for lower urinary tract symptoms (LUTS) indicative of benign prostatic hyperplasia over the years 1999 to 2000, non-treated men with an initial International Prostate Symptoms Score (I-PSS) equal to or lower than 2 were assessed 2 years later for symptom progression. METHODS: A cross-sectional study was conducted in 1999 on 1804 men aged 40 years or older who were living in Madrid. In a telephone interview sociodemographic information was requested and LUTS assessed using the I-PSS. Of 975 men with no LUTS or lower than 2 in this baseline survey, 463 were re-interviewed in 2001. The dependent variable was the change from null/mild to moderate/severe LUTS produced over 2 years. RESULTS: Over the 2-year period, the mean increase in I-PSS score was 2.20 (95% CI, 1.89-2.51). The cumulative incidence of progression from asymptomatic/mild to moderate/severe disease was 9.94% (95% CI, 7.53-13.00). In the multivariate logistic regression model men who lived in a rural setting (OR, 2.70; P = .01) and armed forces, qualified agriculture and fishing workers (OR, 4.11; P = .05) were independently associated with progression. Age and alcohol intake were also found to interact; intake of 0.01-25.99 g/day in men older than 50 years (OR, 0.28; P = .008) was related to a lower frequency of progression than the same alcohol intake in men younger than 50 years (OR, 2.03; P = .380). CONCLUSIONS: After the 2-year period, the incidence of symptom progression was 10% in men aged 40 years or older with an initial I-PSS equal to or lower than 2.

Diagnostic validity of helical CT compared to ultrasonography in renal-ureteral colic.

OBJECTIVES: Helical CT without contrast is currently being evaluated for the diagnosis of renoureteral colic. Ureteral obstruction and other pathologies with similar symptoms can be rapidly identified. This study intends to evaluate the validity of CTh for these patients and to compare it with the ultrasound technique in order to consider the CTh as an efficient diagnostic alternative for these pathologies. METHODS: A diagnostic evaluation study was carried out between January 2004 and December 2006 in patients with persistent renoureteral colic after standard care. They were blindly evaluated by ultrasound and CTh, maintaining the follow up until the "gold standard" confirmation. Qualitative variables were described by frequency and 95%CI and quantitative variables by position and dispersion measures. The Chi2 test was used to compare qualitative variables. Validity indicators and 95% CI were calculated and compared with McNemar test. RESULTS: 124 patients were studied. Lithiasis and the other diagnosis had frequencies of 59.7% and 40.3% respectively. The percentage of lithiasis obtained by ultrasound (92) was 22.8% and by CTh (124) was 59.7%. Validity indicators for CTh were superior to 95%, with 100% sensitivity and positive predictive value. Ultrasound specificity and positive predictive value were 100%, but sensitivity was only 29.6% (p<0.05). CONCLUSION: CTh can be considered a good alternative diagnostic technique in the renoureteral colic management.

Validez diagnóstica de la TAC helicoidal frente a la ecografía en el cólico renoureteral / Diagnostic validity of helical CT compared to ultrasonography in renal-ureteral colic

OBJETIVO: La TAC helicoidal (TACh) sin contraste se evalúa como técnica diagnóstica en el cólico renoureteral. Permite un diagnóstico rápido de obstrucción ureteral y de otras patologías de sintomatología similar. Este estudio pretende evaluar la validez de la TACh frente a la ecografía en el diagnóstico de estos pacientes y plantear su inclusión, como una prueba más, en el algoritmo diagnóstico de esta patología.MÉTODOS: Estudio de evaluación de pruebas diagnósticas realizado entre enero de 2004 y diciembre de 2006 en pacientes valorados por cólico renoureteral no resuelto con atención estándar, estudiándolos de forma ciega mediante ecografía y TACh y siguiéndolos hasta confirmar el diagnóstico con un “patrón oro”. Las variables cualitativas se resumen con su distribución de frecuencias e IC95% y las cuantitativas con medidas de posición y dispersión. Se utilizó el test de χ2 para comparar variables cualitativas. Se calcularon los índices de validez diagnóstica con sus IC95% y se compararon con la prueba de McNemar.RESULTADOS: Se estudió a 124 pacientes, presentando litiasis el 59,7% y otros diagnósticos el 40,3%. Las 92 ecografías efectuadas diagnosticaron un 22,8% de litiasis frente al 59,7% obtenido con 124 TACh. Los índices de validez para la TACh fueron superiores al 95%, con una sensibilidad y valor predictivo positivo (VPP) de 100%. La ecografía presentó una especificidad y un VPP de 100% pero sensibilidad y valor predictivo negativo de 29,6% (p<0,05).CONCLUSIÓN: La TACh puede ser considerada una prueba más a utilizar en el diagnóstico del cólico renoureteral(AU)

OBJECTIVES: Helical CT without contrast is currently being evaluated for the diagnosis of renoureteral colic. Ureteral obstruction and other pathologies with similar symptoms can be rapidly identified. This study intends to evaluate the validity of CTh for these patients and to compare it with the ultrasound technique in order to consider the CTh as an efficient diagnostic alternative for these pathologies.METHODS: A diagnostic evaluation study was carried out between January 2004 and December 2006 in evapatientswith persistent renoureteral colic after standard care. They were blindly evaluated by ultrasound and CTh, maintaining the follow up until the “gold standard” confirmation. Qualitative variables were described by frequency and 95%CI and quantitative variables by position and dispersion measures. The χ2 test was used to compare qualitative variables. Validity indicators and 95% CI were calculated and compared with McNemar test.RESULTS: 124 patients were studied. Lithiasis and the other diagnosis had frequencies of 59.7% and 40.3% respectively. The percentage of lithiasis obtained by ultrasound (92) was 22.8% and by CTh (124) was 59.7%.Validity indicators for CTh were superior to 95%, with 100% sensitivity and positive predictive value. Ultrasound specificity and positive predictive value were 100%, but sensitivity was only 29.6% (p<0.05).CONCLUSION: CTh can be considered a good alternative diagnostic technique in the renoureteral colic management(AU)

Risk of upper gastrointestinal complications among users of traditional NSAIDs and COXIBs in the general population.

BACKGROUND & AIMS: Traditional nonaspirin, nonsteroidal anti-inflammatory drugs (tNSAIDs) have been associated with a 3- to 5-fold increased risk in upper gastrointestinal complications (UGIC). Whether use of selective inhibitors of cyclooxygenase-2 (COXIBs) will translate into a clinically relevant reduced toxicity has not been widely investigated in the general population. METHODS: We conducted a nested case control study using The Health Improvement Network Database identifying 1561 cases of UGIC between January 2000 and 2005. A random sample of 10,000 controls was frequency matched to the cases by age, sex, and calendar year. RESULTS: The adjusted relative risk (RR) of UGIC associated with current use was 3.7 (95% CI: 3.1-4.3) for tNSAIDs and 2.6 (95% CI: 1.9-3.6) for COXIBs. Daily dose was a predictor of increased risk for both tNSAIDs and COXIBs. Users of tNSAIDs with a prolonged plasma half-life or slow release formulations had an augmented risk of UGIC. Overall, the estimate of RR associated with COXIBs was 0.8 (95% CI: 0.6-1.1) compared with current use of tNSAIDs, and, among nonusers of aspirin, the corresponding estimate of RR associated with COXIBs was 0.6 (95% CI: 0.4-0.9). CONCLUSIONS: COXIBs present a better upper gastrointestinal safety than tNSAIDs, although the risk of UGIC for an individual drug is determined by its daily dose and plasma drug exposure in addition to its selectivity for cyclooxygenase-2. Also, concomitant use of aspirin is a strong effect modifier of COXIBs that negates the superior gastrointestinal safety over tNSAIDs in the absence of aspirin use.

[Systematic review about the usefulness and prognostic value of the p53 oncoprotein and proliferation marker Ki-67 for upper urinary tract transitional cell carcinoma]. / Revisión sistemática sobre la utilidad y el valor pronóstico de la oncoproteína p53 y el marcador de proliferación Ki-67 en el car- cinoma de células transicionales del tracto urinario superior.

OBJECTIVES: To perform a systematic review on the expression and prognostic value of the p 53 oncoprotein and Ki 67 proliferation marker in transitional cell carcinoma of the upper urinary tract. METHODS: A systematic review of cohort, prospective and retrospective studies from 1/1/1990 to 11/24/2003 has been undertaken, performing a bibliographic search both manual and electronic in the main databases. 632 works were found using the keywords "ureter, renal and pelvis tumor", and 14 with "ureter, renal and pelvis tumor, and immunohistochemical". RESULTS: 509 patients were studied; they were selected from 7 retrospective studies about the usefulness of p53 and Ki 67 in transitional cell carcinoma of the upper urinary tract published between 1995 and 2002 (three Spanish studies, three Japanese and one North American). Each one analyzes between 37 and 121 cases, with a mean age of 66.8 years (range 63.0-74.7) and a predominance of male sex in 100% of the studies. The pyelocalyceal site was the most frequent in these series. Treatment is another issue taken into consideration in this papers, being nephroureterectomy the most frequently found. The p53 and Ki 67 percentage expression in various studies has been related to clinical and histological factors. Only 5 studies performed a multivariate analysis using Cox regression models. Three of them deal with Ki 67 and two with p53, although one of the p53 studies associates cyclin E determinations. Only two out of three studies about Ki 67 were considered evaluable, because multivariate analysis was not performed in the other one. CONCLUSIONS: 1) There are a few studies and they are very heterogeneous in terms of design, selection criteria, follow-up, and use of prognostic variables. 2) The analyzed studies establish that oncoprotein p53 and proliferation marker Ki 67 are prognostic factors for transitional cell carcinoma of the upper urinary tract, and 3) To perform a meta-analysis was deemed not indicated because of the heterogeneicity of the studies found in our search.

[Variable measurement in urologic clinical research]. / La medición de las variables en la investigación clínica urológica.

Epidemiology develops measurements that allow to quantify the occurrence of disease within the population. There are three types of measurements: frequency measurements, explained in this article; association measurements, between the occurrence of disease and some characteristics, the effect of which on the disease is what they intend to measure; and measurements of the potential impact that modification or disappearance of some risk factors would have on the occurrence of disease in the population. The first objective of epidemiological studies is the knowledge of the frequency of disease. There are three basic measurements of frequency of a disease. Prevalence measures the proportion of people that has it in a given moment. Cumulative incidence measures the proportion of people that convert from non-sick individual to sick individual during a specified period of time. Incidence rate is a measure of the instantaneous strength of occurrence of the disease.

[Statistics as support tool and not as a decision tool]. / La estadística como una herramienta de apoyo y no como una herramienta de decisión.

The use of statistics in medical articles has risen a lot during the last decades, however it is used in a thoughtless manner in many instances. Today, Statistics is the only tool that allows the medical researcher to obtain results and benefits from those studies the relationships of which can not be interpreted from a determinist perspective, because it is a branch of applied mathematics objective of which is to manage and quantify the uncertainty of the available information, to support decision taking. The objective of this article is to review the basic statistical concepts that every doctor should know to be able to perform and/or detect quality research, as well as to underline the most frequent errors committed when interpreting statistical results. We review the general concepts about data synthesis and differentiation of the different types of measurements, hypothesis testing and errors that can be committed doing it, the real meaning of the "p" value, differentiation between statistically significant and clinically relevant results, the importance of confidence intervals as a measure of significance and clinical relevance, the confusion generated between two concepts that are different as standard deviation and standard error, and the criteria that govern the selection of the adequate statistical tests to evaluate relationships between variables.

[Choosing study design in urologic research]. / Elección del diseño de estudio en investigación urológica.

The design of an epidemiological study includes the procedures, methods and techniques by which the researcher tries to obtain valid (avoiding systematic errors or bias) and precise (avoiding random errors) answers to the research question posed. This principal question aimed to be answered is the specific objective of the study, which guides the election of an adequate type of design. The objective of this article is to describe the classification criteria (finality, temporal sequence, directionality, and control of the assignation of different study factors) of the different types of epidemiological studies (experimental, almost-experimental, and observational) and the main advantages, disadvantages, utilities and objectives of each investigation design.

[Design and analysis of a study on reliability and validity of diagnostic tests in urological clinical research]. / Diseño y análisis de un estudio de fiabilidad y validez de pruebas diagnósticas en investigación clínica en urología.

Diagnosis is a process characterized by uncertainty, which the researcher can approach through knowledge based on the theory of probability, and, as such, it is part of the general decision-making process. To use a test is a process that helps to confirm or refuse the initial probability of the patient to be sick. In this article, we analyze the essential characteristics of diagnostic tests and the principles of effective evaluation of the studies about these tests. We explain in detail what reliability of an instrument is, the types of reliability that there are, and how to analyze them. So that, we introduce concepts such as Pearson's correlation coefficient, intra-class correlation coefficient, and Cohen's Kappa coefficient. Another topic described in this article is measurement of validity, defining the types of validity to be considered on an instrument. Finally, we treat the general principles that rule the design and execution of a study for the evaluation of diagnostic tests, the structure followed by these studies, and mainly the analysis, intention of which is to evaluate to what extent that diagnostic test differentiates between subjects with and without the disease studied. We explore the concepts of sensitivity, specificity, predictive values, and probability ratios, and ROC curves are explained.

[Writing an original research article]. / Elaboración de un artículo original de investigación.

Publication of a scientific work is the final and obligatory stage of any research. Among the various existing types of medical publications, the research original article is the prototype of scientific article. Its finality is to communicate the investigation undertaken to the reader in a coherent, clear and precise manner. With that purpose, the discoveries found by the authors as an answer to a hypothesis are presented and discussed. To send the original article to a biomedical journal, the manuscript should present some adequate formal characteristics, in addition to contain scientifically valid information. That can be achieved by complying with the rules past by the International Committee of Biomedical Journal Editors which have been adopted by a great number of scientific journals as publication requisites. The objective of this article is to describe the structure of the various parts (first page, abstract, introduction, material and methods, results, discussion, and bibliographic references) that constitute the format of the research original article, exposing the main adverse to be avoided during its preparation.

Diseño y análisis de un estudio de fiabilidad y validez de pruebas diagnósticas eninvestigación clínica en urología / Design and analysis of a study of reliability and validity of diagnostic tests in clinical research in the urology

El diagnóstico es un proceso caracterizado por la incertidumbre, al que el investigador puede aproximarse a través de conocimientos basados en la teoría de la probabilidad y como tal, forma parte del proceso general de la toma de decisiones. La utilización de una prueba es un proceso que ayuda a confirmar o refutar la probabilidad inicial de que el paciente esté enfermo. En este artículo se analizan las características fundamentales de las pruebas diagnósticas y los principios de evaluación eficiente de los estudios acerca de estas pruebas. Se explica con detalle en qué consiste la fiabilidad de un instrumento, los tipos de fiabilidad que existen y cómo analizarlos. Así se introducen conceptos como el coeficiente de correlación de Pearson, el coeficiente de correlación intraclase y el coeficiente kappa de Cohen. La medición de la validez es otro de los temas descritos en este artículo, definiendo los tipos de validez a tener en cuenta en un instrumento. Finalmente, se abordan los principios generales que rigen el diseño y ejecución de un estudio de evaluación de pruebas diagnósticas, la estructura que siguen estos estudios y fundamentalmente, el análisis, cuyo propósito es evaluar en qué medida el test diagnóstico discrimina entre sujetos con y sin la enfermedad de estudio. Se exploran los conceptos de sensibilidad, especificidad, valores predictivos y cocientes de probabilidad y se explican las curvas ROC. (AU)

La estadística como una herramienta de apoyo y no como una herramienta dedecisión / Statistics as a support tool and not as a decision tool

El uso de la estadística en los artículos médicos se ha incrementado mucho en las últimas décadas, utilizándose, sin embargo, en muchas ocasiones, de un modo irreflexivo. La estadística es, hoy por hoy, la única herramienta que permite al investigador médico obtener resultados y beneficios en aquellos estudios cuyas relaciones no puedan ser interpretadas desde una perspectiva determinista, puesto que es una rama de las matemáticas aplicadas cuya finalidad es manejar y cuantificar la incertidumbre de la información disponible, para apoyar la toma de decisiones. El objetivo de este artículo es repasar los conceptos estadísticos básicos que todo médico debe conocer, para poder realizar y/o detectar una investigación de calidad, así como subrayar los errores que con más frecuencia se cometen al interpretar los resultados estadísticos. Se abordan conceptos generales acerca de la síntesis de datos y la diferenciación de los distintos tipos de medidas, el contraste de hipótesis y los errores que pueden cometerse al realizarlo, el verdadero significado del valor "p", la distinción entre un resultado estadísticamente significativo y clínicamente relevante, la trascendencia del intervalo de confianza como medida de significación y de relevancia clínica, la confusión que se genera entre dos conceptos distintos como son la desviación estándar y el error estándar y los criterios que rigen la elección de la prueba estadística adecuada al evaluar la relación entre variables. (AU)

La medición de las variables en la investigación clínica urológica / The measurement of variables in clinical research in urology

La epidemiología desarrolla medidas que permiten cuantificar la ocurrencia de la enfermedad en la población. Existen tres tipos de medidas: medidas de frecuencia, explicadas en este artículo; de asociación, entre la ocurrencia de enfermedad y determinadas características, cuyos efectos sobre la enfermedad es lo que se pretenden medir; y medidas del impacto potencial que tendría en la población la modificación o desaparición de determinados factores de riesgo sobre la ocurrencia de enfermedad. El conocimiento de la frecuencia de enfermedad es el primer objetivo en los estudios epidemiológicos. Existen tres medidas básicas de frecuencia de una enfermedad. La prevalencia mide la proporción de gente que tiene la enfermedad en un instante concreto. La incidencia acumulada mide la proporción de gente que se convierte, durante un periodo de tiempo especificado, de no enfermo en enfermo. La tasa de incidencia es una medida de la fuerza instantánea de ocurrencia de la enfermedad (AU)

Elección del diseño de estudio en investigación urológica / Selection of study design in urological research

Se denomina diseño de un estudio epidemiológico a los procedimientos, métodos y técnicas mediante las cuales el investigador intenta obtener una respuesta válida (evitando errores sistemáticos o sesgos) y precisa (evitando errores aleatorios) a la pregunta de investigación planteada. Esta pregunta principal que se desea contestar es el objetivo específico del estudio, el cual guía la elección del tipo de diseño adecuado. El objetivo de este artículo es describir los criterios de clasificación (finalidad, secuencia temporal, direccionalidad y control de la asignación de los factores de estudio) de los diferentes tipos de estudios epidemiológicos (experimentales, cuasi experimentales y observacionales) y las principales ventajas, inconvenientes, utilidades y objetivos de cada diseño de investigación (AU)

Elaboración de un artículo original de investigación / Elaboration of a research original article

La publicación de un trabajo científico es la etapa final y obligada de cualquier investigación. Entre los distintos tipos de publicaciones médicas existentes, el artículo original de investigación es el prototipo de artículo científico. Su finalidad es comunicar al lector de forma coherente, clara y precisa la investigación llevada a cabo. Para ello se presentan y discuten los hallazgos encontrados por los autores en respuesta a una hipótesis.Para enviar el artículo original a una revista biomédica, el manuscrito, además de contener una información científicamente válida, debe presentar unas adecuadas características formales. Ello se consigue cumpliendo las normas aprobadas por el Comité Internacional de Editores de Revistas Biomédicas que han sido adoptadas por gran número de revistas científicas como requisitos de publicación.El objetivo de este artículo es describir la estructura de los diferentes apartados (primera página, resumen, introducción, material y métodos, resultados, discusión y referencias bibliográficas) que constituyen el formato del artículo original de investigación, exponiendo los principales errores a evitar en su elaboración (AU)