Índice

·        Resumen

·        Antecedentes

• Medicina Basada en la Evidencia Científica

·        Pasos para la práctica de la medicina basada en la  evidencia a través de las revisiones sistemáticas

• Resúmenes de revisiones sistemáticas de enfermedades respiratorias elaboradas según el protocolo Cochrane, cuyo texto completo se encuentra en la libreria Cochrane

Resumen

El carácter acumulativo del conocimiento científico induce en todo investigador la necesidad de la revisión de la literatura científica relacionada con el tema que aborda. Básicamente es esta causa la que ha determinado que las revisiones de los resultados de las investigaciones realizadas hayan cumplido siempre una función primordial en el desarrollo científico. Está surgiendo un nuevo paradigma para la práctica de la medicina, la medicina basada en la evidencia que requiere nuevas habilidades del médico que incluyen la búsqueda eficiente en la literatura y la aplicación de reglas formales para la evidencia al evaluar la literatura científica. Cada vez es mayor la influencia de la medicina basada en la evidencia en la práctica clínica y en la educación médica

Antecedentes

 El carácter acumulativo del conocimiento científico induce en todo investigador la necesidad de la revisión de la literatura científica relacionada con el tema que aborda. Básicamente es esta causa la que ha determinado que las revisiones de los resultados de las investigaciones realizadas hayan cumplido siempre una función primordial en el desarrollo científico. Sin embargo, el interés más reciente en los trabajos de revisión ha surgido por la enorme proliferación que durante las últimas décadas ha tenido la investigación junto con una multiplicación de las fuentes y medios de acceso a la información. De modo que las revisiones tradicionales de la literatura científica se han visto transformadas metodológicamente, se han introducido métodos estadísticos en el proceso de revisión y se ha hecho hincapié en aplicar, a las nuevas revisiones, los mismos criterios de rigor exigidos en las investigaciones originales.

Está surgiendo un nuevo paradigma para la práctica de la medicina, la medicina basada en la evidencia que requiere nuevas habilidades del médico que incluyen la búsqueda eficiente en la literatura y la aplicación de reglas formales para la evidencia al evaluar la literatura científica. Cada vez es mayor la influencia de la medicina basada en la evidencia en la práctica clínica y en la educación médica.

Los fundamentos  de estos cambio residen en los desarrollos de la investigación clínica durante los últimos 30 años. En 1960, el ensayo clínico con asignación aleatoria era una excepción. En la actualidad, se acepta e prácticamente ningún fármaco puede introducirse en la práctica clínica sin una demostración de la eficiencia del mismo mediante ensayos clínicos. Además, el mismo método de ensayos aleatorizados se aplica de forma creciente a tratamientos quirúrgicos y exámenes diagnósticos. El meta-análisis tiene cada vez una mayor aceptación como método de sintetizar los resultados de una serie de ensayos aleatorizados y, en último término, podría tener un efecto tan profundo en el contexto de las normas de tratamiento como el que poseen los propios ensayos clínicos aleatorios.

Sin restar importancia a otros diseños hemos notado que en nuestro país la mayor parte de las investigaciones sobre enfermedades respiratorias son descriptivas del comportamiento del fenómeno en el tiempo y el espacio, unas pocas se dedican a buscar su causalidad y mas recientemente se ha incrementado la evaluación de la calidad de programas, servicios y sistemas de salud y la experimentación, sobre todo por el médico general integral con la intervención sobre la comunidad para la modificación de conocimientos y algunas evaluaciones de la eficacia de tratamientos, sobre todo propios de la medicina natural y tradicional con una dosis casi nula de revisiones sistemáticas buscando la evidencia científica, en la que todavía hay desconocimiento por una parte considerable del personal médico por lo que queremos mostrar una breve sintesis del diseño de estas que llame a la reflexión en la necesidad de aplicarlas en la práctica médica.

Medicina Basada en la Evidencia Científica

La medicina basada en la evidencia científica es el uso consciente, explícito y juicioso de la mejor evidencia científica disponible para tomar decisión sobre el cuidado de los individuos y colectivos.

Pasos para la práctica de la medicina basada en la  evidencia a través de las revisiones sistemáticas.

*  Identificar el Problema Clínico.

·                    Fundamentación del problema.

·                    Formulación de Interrogantes.

·                    Planteamiento de los objetivos.

*  Elegir la fuente de información más apropiada y Diseñar la estrategia de búsqueda.

*  Valoración crítica

·                    Criterios de inclusión y exclusión.

·                    Evaluación de la calidad de cada estudio.

·                    Recogida de datos.

*  Buscar la evidencia

·                    Procedimientos estadísticos

*  Aplicar en la toma de decisiones

*  Actualizar constantemente la revisión en búsqueda de la mejor evidencia científica

Identificar el Problema Clínico

Se enunciará con claridad y presición el problema objeto de revisión y una argumentación que justifique  la misma.

Los problemas o interrogantes clínicos proceden de la tarea diaria (historia y exploración, causas, diagnostico diferencial, pruebas diagnosticas, tratamiento, prevención, etc.). Aunque algunas se responden directamente otras  necesitan que hagamos un enfoque sistematizado para responderlas.

El primer paso es convertir el problema o caso clínico en una pregunta suceptible de ser respondida. Aunque pueden surgir varias interrogantes dentro de un “caso clínico” se debe elegir la pregunta mas relevante, una vez elegida se debe formular. 

Formular una pregunta es reducirla a términos claros y precisos, básicamente  consiste en dividirla en sus elementos principales, el ejercicio de escribir y descomponerla en sus componentes es útil para simplificarlas y aclararlas, seguir una sistemática, y sobre todo para facilitanos la búsqueda de las "evidencias" o pruebas.

Se debe descomponer en cuatros elementos, a saber:

1. paciente o problema de interés

2. intervención que se va a considerar

3. intervención con la que comparar

4. resultado clínico que se valora

El planteamiento de los objetivos no es una excepción para este diseño.

Elegir la fuente de información más apropiada y Diseñar la estrategia de búsqueda.

Para localizar las evidencias de forma eficaz es recomendable en primer lugar, elegir la fuente de información más apropiada, una vez seleccionada(s) se debe diseñar la estrategia de búsqueda ,a partir de esta, y teniendo en cuenta las características de cada recurso comenzar la búsqueda.
Para una búsqueda rápida se recomienda utilizar los siguientes fuentes:

·                    Medline, LILACS, EMBASE, Cochrane Library, otras bases de datos médicas y paramédicas

·                    Fuentes secundarias (Turning Research Into Practice Database, Center for Reviews and disemination databases, Revistas secundarias, Journals club y CAT banks)

·                    Revistas médicas

·                    Guias de Prácticas Médicas

·                    Internet

·                    Indices y buscadores médicos (Medhunt Medical Worl Search, Hardin Metadirectory ,  Cliniweb, OMNI,  MedWeb , Health Links, Karolinska Institute , MedFinder Smart Medical Web Search)

·                      Literatura gris (Tesis, Informes Internos, revistas sin cuerpo de revisores, fichas de la industria farmacéutica)

·                      Referencias de referencias

·                      Comunicación personal con expertos y autores de investigaciones publicadas y no publicadas

 Valoración crítica

Los criterios de inclusión basan su variabilidad en los objetivos de la investigación, la fundamentación de estos criterios es tan importante como su enunciación, así como el registro de estudios encontrados, incluso los que quedan excluidos.

Como base para la inclusión de los estudios pueden tomarse su diseño, el tamaño muestral, las caracteristicas particulares de los tratamientos o los sujetos, así como el tiempo y localización espacial del estudio.

Existen diferentes métodos e instrumentos, la literatura recoge, aproximadamente, 25 escalas y 9 "checklist" dioferentes para evaluar la calidad y validez de los estudios, siendo una de las mas populares la escala de Jadad, es de comprender que para llevar a cabo esta tarea se necesitará, por lo menos, dos revisores con formación y experiencias diferentes, para evitar la subjetividad.

Pensar siempre en las posibles fuentes de sesgos agrupadas en cuatro categorias fundamentales:

 ·                    Sesgo de selección

·                    Sesgo de realización

·                    Sesgo de desgaste

·                    Sesgo de detección

 El plan de recolección y tabulación de datos con las variables clinicamente interesantes y como una garantia de la no duplicación, también es necesario realizarlo por dos personas, al menos, confrontando los resultados al final para disminuir la posibilidad de errores.

Buscar la evidencia

Los procedimientos estadísticos para obtener los resultados serán:

Definir eventos claves (end-points)

Definir la medida del efecto y parámetro a estimar

Seleccionar modelo para estimar el efecto

Elegir variable principal de salida (outcome)

Enunciar confusores, variables intermedias y modificadores del efecto a controlar

Los resultados deben ser plasmados con claridad, en términos numéricos, si es posible, expresados según la medida del efecto (Diferencia de medias o de proporciones, odds ratio, riesgo relativo, etc..)

Aplicar en la toma de decisiones

Para la aplicabilidad de los resultados debemos garantizar que los pacientes cubiertos por la revisión no sean lo suficientemente diferentes a los del área donde se aplicaran los resultados, que el medio de aplicación no sea muy distinto al del estudio, que se  hayan considerado todos los resultados importantes, se tenga en cuenta las relaciones riesgo/beneficio y costo/beneficio.

Actualizar constantemente la revisión en búsqueda de la mejor evidencia científica

 La mejora y actualización permanente de las revisiones garantiza la vigencia de sus resultados y que se logre cada vez obtener la mejor evidencia asi como permite que los investigadores mantengan su linea de investigación.

Entre las dificultades metodológicas observadas en algunas revisiones están los sesgo de publicación y de selección, la pobre calidad de los estudios incluidos, la falta de sistematización, transperencia y actualización. Un ejemplo de ello es el que presentamos a continuación:

La Colaboración Cochrane, una organización no lucrativa que surgió en respuesta al desafío de la medicina basada en la evidencia científica y que tiene como objetivo preparar, mantener y difundirrevisiones sistemáticas sobre los efectos de la atención sanitaria y que acaba de constituir un centro Cochrane en Cuba tiene tres grupos de revisores de enfermedades respiratorias y establece un protocolo específico para llevar a cabo estas revisiones. Un ejemplo de ello es el que presentamos a continuación:

Resúmenes de revisiones sistemáticas de enfermedades respiratorias elaboradas según el protocolo Cochrane, cuyo texto completo se encuentra en la libreria Cochrane.

Family therapy for asthma in children

Panton J, Barley EA

ABSTRACT

Background: Psychosocial and emotional factors are important in childhood asthma. Nevertheless, drug therapy alone continues to be the main treatment. Treatment programmes that include behavioural or psychological interventions have been developed to improve disturbed family relations in the families of children with severe asthma . These approaches have been extended to examine the efficacy of family therapy to treat childhood asthma in a wider group of patients. This review systematically examines these studies.

Objectives: Recognition that asthma can be associated with emotional disturbances has led to the investigation of the role of family therapy in reducing the symptoms and impact of asthma in children. The objective of this review was to assess the effects of family therapy as an adjunct to medication for the treatment of asthma in children.

Search strategy: We searched the Cochrane Airways Group trials register, Psychlit and Psychinfo.

Selection criteria: Randomised trials comparing children undergoing systematic therapy focusing on the family in conjunction with asthma medication, with children taking asthma medication only.

Data collection and analysis: One reviewer applied the study inclusion criteria.

Main results: Two trials with a total of 55 children were included. It was not possible to combine the findings of these two studies because of differences in outcome measures used. In one study, gas volume, peak expiratory flow rate and daytime wheeze showed improvement in family therapy patients compared to controls. In the other study, there was an improvement in overall clinical assessment and number of functionally impaired days in the patients receiving family therapy. There was no difference in forced expiratory volume or medication use in both studies.

Reviewers' conclusions: There is some indication that family therapy may be a useful adjunct to medication for children with asthma. This conclusion is limited by small study sizes and lack of standardisation in the choice of outcome measures.

Citation: Panton J, Barley EA. Family therapy for asthma in children (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

Methyl-xanthines for exacerbations of chronic obstructive pulmonary disease

Barr RG, Rowe BH, Camargo Jr, CA

ABSTRACT

Background: International guidelines currently recommend the use of methyl-xanthines for exacerbations of chronic obstructive pulmonary disease (COPD) for patients who have incomplete responses to bronchodilators. However, available clinical trials are small and underpowered to evaluate the benefits and risks of methyl-xanthines in this acute setting.

Objectives: To determine the benefit of methyl-xanthines compared to standard care for COPD exacerbations.

Search strategy: Randomised controlled trials (RCTs) were identified from the Cochrane Airways Review Group COPD Register which is a compilation of systematic searches of CINAHL, EMBASE, MEDLINE and CENTRAL and hand searching of 20 respiratory journals. In addition, primary authors and content experts were contacted to identify eligible studies. Bibliographies from included studies, known reviews and texts were also searched.

Selection criteria: Only RCTs were eligible for inclusion. Studies were included if patients presented with acute COPD exacerbations and were treated with either methyl-xanthines (oral or intravenous) or placebo (with or without standard care) early in the acute treatment. Studies also needed to report either pulmonary function or admission results. Two reviewers independently selected potentially relevant articles and selected articles for inclusion. Methodological quality was independently assessed by two reviewers.

Data collection and analysis: Data were extracted independently by two reviewers if the authors were unable to verify the validity of information. Missing data were obtained from authors or calculated from other data presented in the paper. The data were analysed using the Cochrane Review Manager 4.0.4 Studies were pooled to yield weighted mean differences (WMD) or odds ratios (OR) and reported using 95% confidence intervals (95%CI).

Main results: From 28 identified references, 4 RCTs met inclusion criteria (172 patients). Mean change in forced expiratory volume in one second (FEV1) at 2 hours was similar in methyl-xanthine and placebo groups (FEV1 WMD: -8 ml; 95% CI: -85 to 69 ml). The only study to report hospitalization rates showed a non-significant reduction with methyl-xanthines (OR: 0.3; 95% CI: 0.1 to 1.8) among 39 patients. Patients receiving methyl-xanthines had similar improvements in symptom scores, but reported more gastrointestinal side effects (OR: 5.3; 95% CI: 1.3 to 21.0) than patients receiving placebo.

Reviewers' conclusions: There is no evidence to support the routine use of methyl-xanthines for COPD exacerbations. Methyl-xanthines do not appreciably improve FEV1 during COPD exacerbations and cause adverse effects; evidence of their effect on admissions is limited.

Citation: Barr RG, Rowe BH, Camargo Jr, CA. Methyl-xanthines for exacerbations of chronic obstructive pulmonary disease (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

Chemotherapy for non-small cell lung cancer

Non-small Cell Lung Cancer Collaborative Group

ABSTRACT

Background: The role of chemotherapy in the treatment of patients with non-small cell lung cancer was not clear. A systematic review and quantitative meta-analysis was therefore undertaken to evaluate the available evidence from all relevant randomised trials.

Objectives: To evaluate the effect of cytotoxic chemotherapy on survival in patients with non-small cell lung cancer. To investigate whether or not pre-defined patient sub-groups benefit more or less from chemotherapy.

Search strategy: MEDLINE and CANCERLIT searches were supplemented by information from trial registers and by hand searching relevant meeting proceedings and by discussion with relevant trialists and organisations.

Selection criteria: Trials comparing primary treatments of surgery, surgery + radiotherapy, radical radiotherapy or supportive care versus the same primary treatment, plus chemotherapy were eligible for inclusion provided that they randomised non-small cell lung cancer patients using a method which precluded prior knowledge of treatment assignment.

Data collection and analysis: A quantitative meta-analysis using updated information from individual patients from all available randomised trials was carried out. Data from all patients randomised in all eligible trials were sought directly from those responsible. Updated information on survival, and date of last follow up were obtained, as were details of treatment allocated, date of randomisation, age, sex, histological cell type, stage and performance status. To avoid potential bias, information was requested for all randomised patients including those who had been excluded from the investigators' original analyses. All analyses were done on intention to treat on the endpoint of survival. For trials using cisplatin-based regimens, subgroup analyses by age, sex, histological cell type, tumour stage and performance status were also done.

Main results: Data from 52 trials and 9387 patients were included. The results for modern regimens containing cisplatin favoured chemotherapy in all comparisons and reached conventional levels of significance when used with radical radiotherapy and with supportive care. Trials comparing surgery with surgery plus chemotherapy gave a hazard ratio of 0.87 (13% reduction in the risk of death, equivalent to an absolute benefit of 5% at 5 years). Trials comparing radical radiotherapy with radical radiotherapy plus chemotherapy gave a hazard ratio 0.87 (13% reduction in the risk of death equivalent to an absolute benefit of 4% at 2 years), and trials comparing supportive care with supportive care plus chemotherapy gave a hazard ratio of 0.73 (27% reduction in the risk of death equivalent to a 10% improvement in survival at one year). The essential drugs needed to achieve these effects were not identified. No difference in the size of effect was seen in any subgroup of patients. In all but the radical radiotherapy setting, older trials using long term alkylating agents tended to show a detrimental effect of chemotherapy. This effect reached conventional significance in the adjuvant surgical comparison.

Reviewers' conclusions: At the outset of this meta-analysis there was considerable pessimism about the role of chemotherapy in the treatment of non-small cell lung cancer. These results offer hope of progress and suggest that chemotherapy may have a role in treating this disease.

Citation: Non-small Cell Lung Cancer Collaborative Group. Chemotherapy for non-small cell lung cancer (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

Acupuncture for chronic asthma

Linde K, Jobst K, Panton J

ABSTRACT

Background: Acupuncture has traditionally been used to treat asthma in China and is used increasingly for this purpose internationally.

Objectives: The objective of this review was to assess the effects of acupuncture for the treatment of asthma or asthma-like symptoms.

Search strategy: We searched the Cochrane Airways Group trials register, the Cochrane Complementary Medicine Field trials register and reference lists of articles.

Selection criteria: Randomised and possibly randomised trials using acupuncture to treat asthma and asthma-like symptoms. Acupuncture could involve the insertion of needles or other forms of stimulation of acupuncture points.

Data collection and analysis: Trial quality was assessed by at least two reviewers independently. A reviewer experienced in acupuncture assessed the adequacy of the sham acupuncture. Study authors were contacted for missing information.

Main results: Seven trials involving 174 people were included. Trial quality varied and results were inconsistent.
No statistically significant or clinically relevant effects were found for acupuncture compared to sham acupuncture. However the points used in the sham arm of some studies are used for the treatment of asthma according to traditional Chinese medicine. Only one study used individualised treatment strategies.

Lung function could be compared statistically in only 3 trials. Peak expiratory flow rate showed a statistically insignificant increase of 8.4 litres/minute weighted mean difference (95% confidence interval -29.4 to 46.2) when acupuncture was compared to sham acupuncture.

Reviewers' conclusions: There is not enough evidence to make recommendations about the value of acupuncture in asthma treatment. Further research needs to consider the complexities and different types of acupuncture.

Citation: Linde K, Jobst K, Panton J. Acupuncture for chronic asthma (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

Vitamin C for preventing and treating the common cold

Douglas RM, Chalker EB, Treacy B

ABSTRACT

Background: The role of oral ascorbic acid (vitamin C) in the prevention and treatment of colds remains controversial despite many controlled trials. There have also been a number of efforts to synthesize and/or overview the results of these trials, and controversy over what these overviews tell us.

Objectives: The objective of this review was to answer the following two questions:
(1) Does regular high dosage supplementation with vitamin C reduce the incidence of colds?
(2) Does taking vitamin C in high doses at the onset of a cold have a therapeutic effect?

Search strategy: This review currently deals only with published trials from two previously published reviews by Kleijnen 1989 and Hemila 1992.

Selection criteria: Randomised and non-randomised trials of vitamin C taken to prevent or treat the common cold.

Data collection and analysis: Two reviewers independently extracted data and assessed trial quality.

Main results: Thirty trials were included. The quality of the included trials was variable. Vitamin C in doses as high as one gram daily for several winter months, had no consistent beneficial effect on incidence of the common cold. For both preventive and therapeutic trials, there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms. This effect was variable, ranging from -0.07% to a 39% reduction in symptom days. The weighted difference across all of the studies revealed a reduction of a little less than half a symptom day per cold episode, representing an 8% to 9% reduction in symptom days. There was no clear indication of the relative benefits of different regimes or vitamin C doses. However in trials that tested vitamin C after cold symptoms occurred, there was some evidence that a large dose produced greater benefits than lower doses.

Reviewers' conclusions: Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds. There appears to be a modest benefit in reducing duration of cold symptoms from ingestion of relatively high doses of vitamin C. The relation of dose to therapeutic benefit needs further exploration.

Citation: Douglas RM, Chalker EB, Treacy B. Vitamin C for preventing and treating the common cold (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

Vaccines for preventing influenza in healthy adults

Demicheli V, Rivetti D, Deeks JJ, Jefferson TO

ABSTRACT

Objectives: To identify, retrieve and assess all studies evaluating the effects of vaccines on influenza in healthy adults.
To assess the effectiveness of vaccines in preventing cases of influenza in healthy adults.
To estimate the frequency of adverse effects associated with influenza vaccination in healthy adults.

Search strategy: MEDLINE was searched using the strategy of the Cochrane Acute Respiratory Infections Group. The bibliography of retrieved articles, the Cochrane Controlled Trials Register (CCTR), and EMBASE (1990 to 1997) were also searched. Handsearch of the journal Vaccine from its first issue to the end of 1997 (Jefferson and Jefferson, 1996; Jefferson, 1998). We wrote to vaccine manufacturers and first or corresponding authors of studies in the review.

Selection criteria: Any randomised or quasi-randomised studies comparing influenza vaccines in humans with placebo, control vaccines or no intervention, or comparing types, doses or schedules of influenza vaccine. Live, attenuated or killed vaccines or fractions thereof administered by any route, irrespective of antigenic configuration were considered. Only studies assessing protection from exposure to naturally occurring influenza in healthy individuals aged 14 to 60 (irrespective of influenza immune status) were considered.

Data collection and analysis: Both clinically defined cases and serologically confirmed cases of influenza were considered as outcomes according to the authors' definitions. Time off work, complication and hospitalisation rates were considered, together with adverse effects. Vaccine schedules were analysed including one component matching the recommended vaccine (WHO or government recommendations) for the year of the study, and whether they matched the circulating viral subtypes.

Main results: The recommended live aerosol vaccines reduced the number of cases of serologically confirmed influenza A by 48% (95% confidence interval 24% to 64%), whilst recommended inactivated parenteral vaccines had a vaccine efficacy of 68% (95% confidence interval 49% to 79%). The vaccines were less effective in reducing clinical influenza cases, with efficacies of 13% and 24% respectively. Use of the vaccine significantly reduced time off work, but only by 0.4 days for each influenza episode (95% confidence interval 0.1 to 0.8 days). Analysis of vaccines matching the circulating strain gave higher estimates of efficacy, whilst inclusion of all other vaccines reduced the efficacy.

Reviewers' conclusions: Influenza vaccines are effective in reducing serologically confirmed cases of influenza A. However, they are not as effective in reducing cases of clinical influenza. The use of WHO recommended vaccines appears to enhance their effectiveness in practice.

Citation: Demicheli V, Rivetti D, Deeks JJ, Jefferson TO. Vaccines for preventing influenza in healthy adults (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

Zinc for the common cold

Marshall I.

ABSTRACT

Objectives: Interest in zinc as a treatment for the common cold has grown following the recent publication of several controlled trials. The objective of this review was to assess the effects of zinc lozenges for cold symptoms.

Search strategy: A search was made of the Cochrane Controlled Trials Register, MEDLINE, EMBASE and reference lists of articles. Searches were run to the end of 1997.

Selection criteria: Randomised double blind placebo-controlled trials of zinc for acute upper respiratory tract infection or cold.

Data collection and analysis: Two reviewers independently extracted data and assessed trial quality.

Main results: Seven trials involving 754 cases were included. With the exception of one study, the methodological quality was rated as medium to high. For most outcome measures different summary estimates were used across the studies to describe the duration, incidence and severity of respiratory symptoms. This limited the ability to pool results. Results from two trials (~~ 04 - Mossad~~; ~~ 08 - Smith~~) suggested zinc lozenges reduced the severity and duration of cold symptoms. However, there was significant potential for bias, and further research is required to substantiate these findings. Overall, the results suggest that treatment with zinc lozenges did not reduce the duration of cold symptoms.

Reviewers' conclusions: Evidence of the effects of zinc lozenges for treating the common cold is inconclusive. Given the potential for treatment to produce side effects, the use of zinc lozenges to treat cold symptoms deserves further study.

[This abstract has been prepared centrally.]

Citation: Marshall I. Zinc for the common cold (Cochrane Review). In: The Cochrane Library, 2, 2001. Oxford: Update Software.

 Fecha de realizado: 2004

Autoras:

Dra. Nelsa María Sagaró del Campo

Dra. Meydis María Macias Navarro

Datos de la autora principal:

Médico Especialista en Medicina Familiar y Bioestadística

Profesor Asistente de la Universidad Médica de Santiago de Cuba.

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