Health care literature, though better organized than other knowledge areas, is still cumbersome enough to make effective searching difficult and large retrievals commonplace. Subject searching (for drugs and diseases) is useful for searching an entire database, but a different approach is needed to limit retrieval to articles that health professionals should use for patient care.
Many different groups, such as basic scientists, clinical researchers, health practitioners, eductors, and administrators, produce publications. Their written work ranges from idea papers, which include editorials and case reports, to wet laboratory and animal experimental studies, to small early studies with humans.
Another important category is the reports in the applied clinical literature about the large, carefully controlled trials done in hospitals and institutions with human participants. These trials are the studies that health care professionals should rely on to keep up-to-date and solve patient care problems. These trials have actual evidence that the changes in health care under investigation are proven advances. The applied clinical trials answer the following questions:
1. What caused the disease or disorder? (etiology)
2. How can I decide what the disease or disorders is? (diagnosis)
3. What happens to people with the disease over time? (prognosis/natural history)
4. How can I treat (or prevent) the disease/disorder? (therapy)
Only a fraction of the millions of citations in MEDLINE, CINAHL, EMBASE, and other related databases actually are of reports of applied clinical trials that address the four questions above. Most citations are reports of preparatory work completed before the applied clinical trials can be done. Applied clincal studies are unique in the manner in which they are produced (their study methods).
Authors refer, in their titles and abstracts, to the methods used in the research, and database indexes index these methodologies as keywords describing the articles. Searchers can use the methods textwords and subject headings to only retrieve papers that have sound research methods and can, therefore, be used directly in patient care. We will describe the study methodologies used in each category, list appropriate index and textwords (Table 1), and given search examples of how to use methodology terms for search filtering.
Table 1 Search Terms for Clinical Trials Research MeSH CINAHL Searching Terms For Comparative And Clinical Studies comparative study comparatives studies clinical trial (pt) clinical trials Searching Terms For Therapy double-blind method duble blind studies random allocation random sampling randomized controlled trial (pt) randomized trials multicenter study (pt) placebos placebos Textwords random: double blind mask: placebo Searching Terms For Diagnosis sensitivity a#d specificity sensitivity (research) predictive value of tests specificity (research) ROC curve predictive validity false positive reactions flase negative reactions false negative reactions false positive reactions Textwords sensitivity specificity false reaction: predictive value: ROC Searching Terms For Etiology/Causation case-control studies retrospective studies retrospective studies case studies cohort studies case control studied longitudinal studies cohort studies prospective studies longitudinal studies follow-up studies prospective studies cross-sectional studies causal attributes odds ratio odds ratio risk risk factors causality random sampling risk factors randomized controlled trial (pt) Textwords cohort case control risk and (revelant or factor:) etiol: or aetiol: causation Searching Terms For Prognosis/Natural History cohort studies cohort studies longitudinal studies longitudinal studies follow-up studies prospective studies prospective studies retrospective studies morbidity morbidity mortality mortality incidnece prevalence Textwords prognos: natural history inception cohort clinical course Searching Terms For Meta-Analysis meta-analysis meta analysis Textwords metaanalysis meta analysis meta-analysis overview
Report of applied clinical research have these two common features: