W. Ashraf et al., AN EXAMINATION OF THE RELIABILITY OF REPORTED STOOL FREQUENCY IN THE DIAGNOSIS OF IDIOPATHIC CONSTIPATION, The American journal of gastroenterology, 91(1), 1996, pp. 26-32
Objectives: To investigate the reliability of reported stool frequency
in the diagnosis of constipation. Methods: Our criterion for the diag
nosis of idiopathic constipation was less than or equal to 3 stools pe
r week for greater than or equal to 6 months, Subjects who believed th
at they met this criterion were invited to participate. Daily stool fr
equency was recorded over a 4-wk study period, and all stools were wei
ghed during the final week. A colon transit study and anorectal manome
try were performed at the beginning and at the end of the study. Resul
ts: On review of stool diaries from 45 subjects who described chronic
constipation and who completed the 4-wk study, only 22 (49%) actually
satisfied our criterion for idiopathic constipation. The remaining 23
(51%) subjects, although describing constipation, had, on average, 6 s
tools/wk. A history of psychiatric illness was 5 times more frequent a
mong those whose bowel symptoms correlated poorly with objective measu
res. Measures of difficult defecation were similar in the two groups.
Mean colon transit time was significantly longer and correlated closel
y with stool weight only in subjects who truly were constipated (p < 0
.05). Anorectal manometry was not helpful in discriminating between th
ose who satisfied our criterion for constipation and those who did not
. Conclusions: Defining constipation on the basis of a patient)s repor
ted stool frequency may prove misleading; the diagnosis of idiopathic
constipation should be supported by the use of stool diaries and a col
on transit study.