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By and
large, constipation remains an unpopular topic for research with
a perception that there is little advance to be made. Yet much
that is quite basic to the management of this condition remains
unknown. As constipation causes distress to so many people, it
is surely opportune for more effort to be devoted to improving
its relief.
Case
Study Exercise 1
A
comparative trial of three laxative preparations, a colonic stimulant,
a combination of a stimulant and a softener, and a bulking agent,
was carried out. A parallel group, randomized, unblinded design
was used, lasting five weeks, with 100 participants in each arm.
Subjects, who were patients recruited from family practice with
complaints of constipation, were assessed over the first week
on their previous laxative medication (if any) and were then encouraged
to titrate the laxative allocated to them until their bowel function
was satisfactory. These are some of the results:
Mean
Bowel Movement Frequency (per week) with standard
deviation
|
|---|
| | Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
| Prior
to Study
| 3.8
(1.4)
| 4.2
(1.3)
| 4.3
(0.9) N.S.
|
|---|
| End
of Study
| 6.8
(1.9)
| 7.5
(3.0)
| 6.4
(2.2) N.S.
|
|---|
|
Percentages
of patients constipated at end of trial
|
|---|
| Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
32%
| 14%
| 28%
|
p
< 0.001 for difference between Softener and Combined
Softener and Stimulant
p
< 0.025 for difference between Combined Softener
and Stimulant and Bulking Agent
p
> 0.5 for difference between Softener and Bulking
Agent
Chi
square tests
|
|
Cumulative
percentages of patients experiencing adverse effects
|
|---|
|
| Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
Colic
| 20%
| 26%
| 18%
|
|---|
p
> 0.25 for differences between groups
|
|
Cumulative
percentages of patients experiencing adverse effects
|
|---|
|
| Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
Flatulence
| 36%
| 12%
| 30%
|
|---|
p
< 0.001 for difference between Softener and Combined
Softener and Stimulant
p<
0.005 for difference between Combined Softener and
Stimulant and Bulking Agent
p
> 0.25 for difference between Softener and Bulking
Agent
|
|
Cumulative
percentages of patients experiencing adverse effects
|
|---|
|
| Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
Nausea
| 31%
| 18%
| 28%
|
|---|
p
< 0.05 for difference between Softener and Combined
Softener and Stimulant
p>
0.5 for difference between Combined Softener and Stimulant
and Bulking Agent
p
< 0.1 for difference between Softener and Bulking
Agent
Chi
square tests
|
|
Mean
daily volumes of laxative (ml) with standard deviations
|
|---|
| Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
| 41.8
(16.3)
| 25.2
(11.1)
| 342
(184.6)
|
p
< 0.04 for difference between Softener and Combined
Softener and Stimulant
p>
0.0005 for difference between Softener or Combined
Softener and Bulking Agent
t
tests
|
|
Cost
of mean doses of laxative (per week)
|
|---|
| Softener
| Combined
Softener and Stimulant
| Bulking
Agent
|
|---|
| $2.32
| $10.05
| $1.71
|
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Question
10.1
What
conclusion can be drawn from these results about the effectiveness
of the three laxatives?
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