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Example 1: A surgeon performs a new procedure for a
life-threatening condition on 20 patients. Ten patients survive.
Two possible papers can be considered:
1A. A description of all treated patients and follow-up,
with calculation of mortality risk. No comparison group is
included.
1B. The same as 1A, except that the treated group is
compared with a historical group from the same institution
to compare mortality risk.
Example 2: Data were collected on patients who had
bone marrow depression at 1 hospital. Potential risk factors,
including drugs known to induce bone marrow depression,
were assessed for all patients. The investigators assessed
whether bone marrow depression was still present after 1 year
among patients who received 1 of 2 drugs used to treat the
same disease. Two papers can be written on the basis of these
data:
2A. A description of all patients with bone marrow
depression and the frequency of potential risk factors for
bone marrow depression.
2B. A comparison of the risk for persistent bone marrow
depression after 1 year, for either drug, with calculation
of the absolute and relative risks for persistence.
Example 3: In 1 hospital, a subset of patients hospitalized
with Escherichia coli–induced hemolytic–uremic syndrome
(HUS) developed neurologic symptoms during their stay. Demographic
and clinical characteristics of patients with HUS were
collected. Two papers can be considered:
3A. A description of only patients who had HUS and
neurologic symptoms.
3B. A comparison to assess whether the risk for neurologic
symptoms was higher in male than in female patients
with HUS.
Distinguishing Case Series From Cohort Studies
Olaf M. Dekkers, MD, PhD, MA, MSc; Matthias Egger, MD, MSc; Douglas G. Altman, DSc; and Jan P. Vandenbroucke, MD, PhD
发表于 2012-1-25 14:41
