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Clinical Research: Constipation Sections
Author Biography
Introduction
Currently Selected Section: What is constipation?
Understanding the problem
Objective Measurement
Subjective Measurement
Measuring Components
Precipitating Factors
Therapeutic Comparisons
Research Questions
Conclusion




Chapter 3: Methods for Clinical Research in Constipation: What is Constipation?
 

Constipation as a symptom

The first point to recognize about constipation is that it is a symptom, not a disease or a sign. This fact introduces a tension into the investigation of constipation which is not present in the investigation of some other symptoms, such as pain; namely the fact that certain objectively measurable criteria exist which can be taken to indicate the presence of constipation in an individual or a population. These criteria may be insisted upon by drug regulatory authorities, for instance, in adjudicating whether a new therapy can be licensed for the treatment of constipation. However, particular patients may complain of constipation when their symptoms do not satisfy the criteria for the symptom.


Different definitions of constipation

Doctors and patients can mean different things when they talk about constipation.

Epidemiological studies have shown that 95% (Drossman et al., 1982) to 99% (Connell et al., 1965) of a healthy population defecate at least three times per week. These findings have informed what are sometimes referred to as the "Rome criteria" (Drossman et al., 1990), which are often used to define constipation.

Table 2.1 "Rome criteria" Definition of Constipation
(Drossman et al., 1990)

The presence of two or more of the following symptoms for at least three months:

  • Straining at least 25% of the time
  • Hard stools at least 25% of the time
  • Incomplete evacuation at least 25% of the time
  • Two or fewer bowel movements per week

 

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