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2. Clinical information sources

Best Evidence/Clinical Study Types

“The best type of study, or evidence, is determined by the type of question being asked. A systematic review or meta-analysis of studies from the best stated type provides more reliable evidence than an individual study.”

Meta Analysis

A systematic review uses a qualitative method in the collection and inclusion of studies. The results of those independent studies that have met the requirements are then synthesized, summaries are produced and conclusions may be used to evaluate therapeutic effectiveness, plan new studies, etc.

The term Meta analysis is often used interchangeably with that of a systematic review but strictly speaking they are not the same. Both imply methods of combining the results of independent studies. But while a systematic review process implies a "qualitative method" a meta analysis implies "quantitative methods" or statistical methods.

Some systematic reviews employ both the qualitative and quantitative methods ie. Cochrane Systematic Reviews

What is the clinical problem?


Question types

Therapy

  • Best evidence: systematic review

    Database search for systematic reviews:EBM reviews: Cochrane database of systematic reviews via Ovid or MEDLINE via Ovid

    • "Evidence based medicine reviews" limit or
    • 'Systematic reviews' under 'Publication type' limit or
    • 'Meta analysis' under 'Publication type' limit

    Best primary study type: randomized controlled trial

    A clinical trial where at least one test treatment and one control treatment, often placebo, are randomly allocated to patients.

    Database Search for best study: MEDLINE

    use clinical queries limit or filter terms

Diagnosis

  • Best Evidence: Systematic Review

    Database Search for Systematic Reviews: MEDLINE via Ovid

    • "Evidence Based Medicine Reviews" limit or
    • 'Systematic Reviews' under 'Publication type' limit or
    • 'Meta Analysis' under 'Publication type' limit

    Best Primary Study Type: Cross-sectional analytic study

    Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time.

    Database Search for Best Study: MEDLINE

    Use Clinical Queries Limit or filter terms

Aetiology

  • Best Evidence: Systematic review.

    Database Search for Systematic Reviews: MEDLINE via Ovid

    • "Evidence Based Medicine Reviews" limit or
    • 'Systematic Reviews' under 'Publication type' limit or
    • 'Meta Analysis' under 'Publication type' limit

    Best Primary Study Type: Cohort study/Case-control study

    Cohort Studies Cohorts are defined populations. A Cohort Study is an observational study in which a defined population is followed over a period of time. The outcomes of people in different subsets of the cohort are compared, to examine exposures to a particular factor of interest or an intervention. Cohort studies can be either prospective or retrospective.

    Case-Control Studies A study that compares people with a specific disease or outcome of interest to people from the same population without the disease or outcome (Controls). The study then tries to find links between the outcome and prior exposure to particular risk factors. Case-control studies are usually retrospective.

    Database Search for Best Study: MEDLINE

    Use Clinical Queries Limit or filter terms

Prognosis

  • Best Evidence: Systematic Review

    Database Search for Systematic Reviews: MEDLINE via Ovid

    • "Evidence Based Medicine Reviews" limit or
    • 'Systematic Reviews' under 'Publication type' limit or
    • 'Meta Analysis' under 'Publication type' limit or

    Best Primary Study Type: Cohort study

    Cohorts are defined populations. A Cohort Study is an observational study in which a defined population is followed over a period of time. The outcomes of people in different subsets of the cohort are compared, to examine exposures to a particular factor of interest or an intervention. Cohort studies can be either prospective or retrospective.

    Database Search for Best Study: MEDLINE

    Use Clinical Queries Limit or filter terms