Five steps of Evidence-based medicine. The first step of Evidence-based medicine. Definition of clinical problem using principle PICO

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Department of Clinical pharmacology and Evidence-based medicine

Discipline Evidence-based medicine

Third year

Specialty 051301”General medicine”

Informational-didactic block

Foundation of Evidence-based medicine

Practical training #8

Theme ”Five steps of Evidence-based medicine. The first step of Evidence-based medicine. Definition of clinical problem using principle PICO”

interference evidence medicine

Steps in practice of Evidence-based medicine

A general practitioner has to make a decision about certain person's health every day. If he is ill, what stage, what is the matter? What is his disease? Are there more effective and safe methods of specifying diagnoses, treatment? Are these methods applicable to a particular person? In addition there are other important questions e.g. what prognosis of disease is it. What methods of prevention are there? There are some other questions.

According approximate assessments only 20-30% all interferences, using in medicine are based on good quality investigations. You can cite a whole number of examples of investigations, which efficiency is proved, but they haven't used in practice for a long time. And vice versa many interferences, which harm is proved very well have been using for a long time. The most patients are cured right by their doctors according the best scientific evidence. It is explained that doctors usually cure the same patients from day to day. The right ways of patient's managing are known very well. Nearly one-fifth of all patients are patients, who suffer from illnesses which are less known by doctor. To manage these patients right the doctor needs to receive additional information, but he usually can't get it.

First of all amount of scientific medical information is very big. It is known 40.000 biological and medical magazines were published 20 years ago. 2 million articles were published every year. In 2000 amount of articles was about 4 million a year. Nowadays this amount is more.

Let us assume that If 1% from 4-5 million published articles were connected with doctor's practice he would have to read about 100 articles every day.

There are some sociological facts in literature, that doctors, who are teachers, spend average 2 hours a week on reading special literature

If you look at other groups of people you will see more unattractive picture.

· Scientists 45 minutes

· Students 60 minutes

· Interns don't read

· Residents 10 minutes

· 50% of doctors didn't read an article last year

To cope with problem extracting necessary information the doctor needs systematic work, its skills are given by evidence-based medicine.

Five steps are appropriated in practice of evidence-based medicine

1. Determination problem or question It is very important to formulate a question for every patient. It helps to think and understand which information is necessary for its decision. It's important to determine type of proof, which is necessary to answer for the question. Is question was formulated correctly; it's possible to get terms, which are making search more effective. As a result the probability of finding necessary proof for every patient increases.

2. Search of proof, which provides answer for the question.

It's necessary to reveal suitable sources of information and create strategy for the search.

3. Cut off score of proof according to its reliability and relevance (practical applicability).

Demonstrative information (of investigation) has different forms- from wide-ranging RCT, which include many centers, to small investigation of medical care cases. The approaches to quality rating information could change, but it's important to answer to three questions:

-what do these results mean?

-can we trust these results?

-are they applicable to our practice?

4. The usage of results for certain patient.

Variants of using the results of investigation and integration tools are existing. It's important to choose suitable one for certain case.

5. Evaluation of results of interference.

It's held according to the answers for existing questions. Do behavior changes lead to the expected effects? Which advantages do we get in the process of using evidence based practice?

Formulation of clinical question

One of the major skills, which is necessary for the practice of evidence based medicine, is correct formulation of clinical questions.

In order to be useful these questions should meet the two major requirements- they must be suitable for certain clinical case and they must be formulated in such way, that it could be possible to find answer. As far as search is made in computer data bases, the question should be expressed in formalized query of searching engines, in order to get relevant and exact searching results.

The correct question- is question which is connected with problem, frontal question. It's differing from questions which are asked by curious and inexperienced students. Inexperienced student ask background questions- what is the origin of edema? What is the causative agent? What are the itching causes? They could be interesting, but they don't directly lead to the answers, which are important for the patient.

The supporters of evidence based medicine have offered peculiar “anatomy” for the question building, the name of which include four composes with creation of PICO formula. It allows medical practitioners to determine four components of good formulating question:

- Population or Patients- (Who is meant?)

- Intervention- What is made with patients and what is happening to them?

- Comparison (- What is the alternative?)

- Outcomes (-What is the result of intervention or effect, whereat are we and patient oriented? And what are we trying to reach?

The following example (Chart 1) illustrates of components of PICO.

Question: What is the best primary therapy for the arterial hypertension in advanced age?

Chart 1. Clinical question and components of PICO.

Types of clinical questions

During the solution to the problems of health care, it's important to determine the type of question.

Questions may concern

-clinical data

-symptoms of disease

-prognosis

-a etiology and causes of disease

-harm and risks

-diagnostics tests

- differential diagnosis

- quality of life

-treatment

- cost effectiveness and other aspects of health and medical services.

In order to create strategies of informational search 5 general clinical questions could be distinguish.

Treatment (therapy) and prevention- questions, which concern treatment (intervention, which are directed at changes of clinical course)of patient and what kind of results could different treatment modes have. This group can also include the prevention aspects.

Diagnostics- questions about accuracy rate and clinical utility of concrete test.( Will this test bring enough good for certain patient. Accuracy is evaluated according the coincidence of test's result with the results of standard test.

Prognosis- questions which are connected with future patient's condition, duration and quality of his life, according the choice of the intervention.

Aetiology and harm- questions about connection between disease and possible causes of it (harm and risks), including the risks, which is connected with medical intervention.(medicine, ect.)

Cost efficiency - questions, which are connected with cost efficiency of intervention (medical, diagnostic)

In such way, evidence based medicine requires reading of articles in suitable time and then according to the received information it changes behavior. Different types of questions can be considered according the certain problem.( arterial hypertension among the senior people)

Harm and risks-Is the using of ticlopidine leads to the decrease of hemorrhages during the long-lasting prevention of cardiovascular diseases in comparison with aspirin?

Cost efficiency. Is usage of p- adrenoceptor antagonists more effective than usage of diuretics in prevention of cardiovascular diseases and general mortality among the people who suffer from arterial hypertension?

Therapy . During the treatment of arterial hypertension in senior age, which kind of hypotensive therapy( among the groups of hypotensive medicines) leads to mortality decrease?

For differentте types of questions there are different kinds of evidence and sources. In order to organize effective search for getting the evidence it's necessary to correlate type of question with suitable type( design) of the most evident research.

The following kinds of evidential data match the major types of questions.

-the frequency of events- register, cohort study , popularity (cross-sectional study)

- risk- cohort study, RCT

- prognosis- cohort study, RCT

- treatment (therapy) - RCT

- prevention- RCT

- reason- cohort study, case-control studies, RCT

- economic efficiency- systematic reviews, RCT, systematic reviews, decision analysis.

Final Control of Knowledge.

1. List the 5 stages in practice of evidence based medicine?

2. Which are the peculiarities of every stage?

3. Determine 5 components of well formulated clinical question?

4. List types of the most evident data which correspond to main types of questions?

5. Formulate one clinical question according to the principles of PICO?

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