Baseline comparisons in surgical trials.
BACKGROUND
Baseline measurements are an essential component of clinical trials. They should establish that the groups involved are clinically equivalent so that any observed differences can be attributed to the intervention under evaluation. The objective of this study was to review the use of baseline comparisons in surgical trials.


METHODS
A standardized format was used to evaluate 206 surgical trials published within 10 prestigious journals between January 1997 and December 1999.


RESULTS
One hundred and fifty-one (73%) of the trials used the first table in the article to record baseline data. More than one-quarter of the trials declared less than five items and one-third of the trials inappropriately used 'P-values' as a measure of baseline equivalence. Only nine of the 54 multicentre studies (17%) mentioned the individual centres as possible confounding factors.


CONCLUSIONS
Greater attention needs to be paid to baseline comparisons in surgical trials. One way of developing this type of critical ability is to use a checklist while reading a surgical trial of interest. Good resources include the CONSORT Statement by a group of prominent international biostaticians and the CLEAR (Critical Literature Evaluation and Research) Courses run by the Royal Australasian College of Surgeons.
University Department of Surgery at Royal Perth Hospital, Western Australia, Australia. jchall@cyllene.uwa.edu.au
John C
JC
Hall
Jane L
JL
Hall
D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D003625:Data Collection / Q000706:statistics & numerical data*; D006801:Humans; D016555:Matched-Pair Analysis; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000706:statistics & numerical data*