To the Editor:
The study by Manoucheri and colleagues1 in the April 1999 issue compared 4 bowel preparations for flexible sigmoidoscopy and found no difference among them. We noticed a higher percentage of “poor” and “awful” preparations in patients who were allowed to eat dinner and breakfast before the procedure (20.7% for group A) compared with those preparations for which the patient was restricted to a light dinner and was instructed to have nothing by mouth after midnight (14.1%, 9.9%, and 12.2% for groups B, C, and D, respectively).
We reanalyzed the data, comparing group A with groups B, C, and D using “good and fair” and “poor and awful” results as outcomes. The new data table is:
Chi-square analysis yielded an obtained value of 5.255 with P=.02.
It appears that the critical difference between the preparations is whether the patient ate before the examination. If he or she ate, it was more likely that the result of the preparation would be poor or awful. Whether oral phosphosoda or 1 or 2 enemas were used does not seem to matter.
On the basis of this information, we will continue to advise our patients to have a clear liquid dinner and have nothing by mouth after midnight before their flexible sigmoidoscopies.
—James Dunlay, MD
Steven Arenberg
Baltimore, Maryland