循证实践的第二步是证据查找 ，检索词的选用需要参考问题构建时的PICO四个要素。It is important when searching for evidence that search terms are referred back to your original PICO question.
In the previous section, we learned how to construct a well-built clinical question. Using that question, we will move on to the literature search.
案例: In patients with type 2 diabetes and obesity, is bariatric surgery more effective than standard medical therapy at increasing the probability of remission of diabetes? It is a therapy question and the best evidence would be a randomized controlled trial (RCT). If we found numerous RCTs, then we might want to look for a systematic review. |
Constructing a well-built clinical question can lead directly to a well-built search strategy. Note that you may not use all the information in PICO or well-built clinical question in your MEDLINE strategy. In the following example we did not use the term “male.” We also did not include the word therapy. Instead we used the Clinical Query for Therapy or the publication type, randomized controlled trial, to get at the concept of treatment. However, you may consider the issue of gender later when you review the articles for applicability to your patient.
PICO | Clinical Question | Search Strategy |
| Patient / Problem | obese, diabetes type 2, male | diabetes type 2, obesity |
| Intervention | stomach stapling (gastric bypass surgery; bariatric surgery) | bariatric surgery |
| Comparison (if any) | standard medical care | |
| Outcome | remission of diabetes; weight loss; mortality | |
| Type of Question | therapy | (see below) |
| Type of Study | RCT | Clinical Query – Therapy/narrow or Limit to randomized controlled trial as publication type |
证据查找的三个主要步骤:
1. Identify terms to fit your PICO question
2. Look for secondary sources
3. Search for primary sources
1. Identify terms to fit your PICO question
| Patient | Intervention | Comparison | Outcome |
|---|---|---|---|
2. Look for secondary sources
Guidelines: UK National Library for Health, NICE, SIGN; US National Guidelines Clearinghouse; Canadian Medical Association; New Zealand Guidelines Group.
CATs: CAT Crawler
Evidence-Based Summaries: Bandolier, Clinical Evidence
Structured Abstracts: EBM Online, ACP Journal Club
Systematic Reviews: Cochrane Library
To search several of the databases simultaneously you can use: www.tripdatabase.com
Guidelines: UK National Library for Health, NICE, SIGN; US National Guidelines
3.Search for Primary Sources
Use methodological filters to target the right type of study. For instance, PubMED filters for:
therapy
diagnosis
prognosis
etiology
