Author Affiliations: Departments of Ambulatory Care and Research, South Texas Veterans Health Care System and Medicine, University of Texas Health Sciences Center at San Antonio, San Antonio (Drs Richardson and Williams); Department of Medicine, Wake-Forest University School of Medicine, Winston-Salem, NC (Dr Wilson); Departments of Pediatrics and Internal Medicine and the Center for Evidence-Based Medicine and Population Health, the University of Texas Health Sciences Center at Houston (Dr Moyer); and Department of Medicine and Office of the Dean, Faculty of Medicine, University of Toronto, Ontario (Dr Naylor). The original list of members (with affiliations) appears in the first article of the series (JAMA. 1993; 270:2093-2095). A list of new members appears in the 10th article of the series (JAMA. 1996;275:1435-1439). The following members of the Evidence-Based Working Group contributed to this article: Eric Bass, MD, MPH, Gordon H. Guyatt, MD, MSc, Les Irwig, MBBCh, PhD, and Hui Lee, MD, MSc.
Users' Guides to the Medical Literature Section
Editor: Drummond Rennie, MD, Deputy Editor.
Clinicians rely on knowledge about the clinical manifestations of disease
to make clinical diagnoses. Before using research on the frequency of clinical
features found in patients with a disease, clinicians should appraise the
evidence for its validity, results, and applicability. For validity, 4 issues
are important—how the diagnoses were verified, how the study sample
relates to all patients with the disease, how the clinical findings were sought,
and how the clinical findings were characterized. Ideally, investigators will
verify the presence of disease in study patients using credible criteria that
are independent of the clinical manifestations under study. Also, ideally
the study patients will represent the full spectrum of the disease, undergo
a thorough and consistent search for clinical findings, and these findings
will be well characterized in nature and timing.
The main results of these studies are expressed as the number and percentages
of patients with each manifestation. Confidence intervals can describe the
precision of these frequencies. Most clinical findings occur with only intermediate
frequency, and since these frequencies are equivalent to diagnostic sensitivities,
this means that the absence of a single finding is rarely powerful enough
to exclude the disease. Before acting on the evidence, clinicians should consider
whether it applies to their own patients and whether it has been superseded
by new developments. Detailed knowledge of the clinical manifestations of
disease should increase clinicians' ability to raise diagnostic hypotheses,
select differential diagnoses, and verify final diagnoses.
Richardson WS, Wilson MC, Williams, Jr JW, Moyer VA, Naylor CD, for the Evidence-Based Medicine Working Group . Users' Guides to the Medical LiteratureXXIV. How to Use an Article on the Clinical Manifestations of Disease. JAMA. 2000;284(7):869-875. doi:10.1001/jama.284.7.869