To the Editor:
Dr. Bowrey and colleagues reviewed the effects of medical
antireflux therapy and fundoplication and concluded that “fundo-
plication has been constantly shown to ameliorate reflux-induced
asthma; results are superior to the published results of antisecre-
tory therapy.”
1
I believe that it is premature to arrive at this
conclusion. Published studies of the relationship between gastro-
esophageal reflux (GER) and asthma, and the effects of antireflux
therapy on asthma are conflicting.
2–4
Although some reports have
concluded that antireflux therapy improves asthma control, others
were unable to demonstrate any benefit.
3,4
Critical review of the
literature on both the effects of medical antireflux therapy and
fundoplication demonstrates that the literature is conflicting and a
clear consensus is not evident.
3,4
Further blinded, randomized,
placebo-controlled clinical trials of both the effects of medical and
surgical antireflux therapy in asthma patients are required to an-
swer these important questions.
Many studies have not confirmed that GER or acid perfusion of
the esophagus worsens asthma, or that treating GER improves
asthma.
5–7
Moreover, the Cochrane collaboration recently con-
cluded that the available data did not support the hypothesis that
treating GER improved asthma.
8
We recently published critical
reviews of the effects of both medical and surgical antireflux
therapy; both seem to improve asthma symptoms but do not
improve pulmonary function.
3,4
A major problem with conducting
asthma therapy trials is the large placebo or “benefit of entering a
trial” effect. Patients in the placebo arm of asthma therapy trials
generally experience a 30 to 40% improvement.
9 –10
The placebo
effect is due to several factors including the benefits of patient
education, proper asthma medication delivery device technique,
adherence to prescribed drug regimens, and regular medical fol-
low-up that asthma patients receive while participating in research
trials.
3
Unless the trial design includes a placebo-controlled group
for comparison, it is unclear whether improvement is due to the
treatment or to the benefits of participating in the trial. Only two of
surgical studies included control groups.
11–12
The others were
uncontrolled case series or retrospective reviews and were subject
to the limitations already noted.
4
Conclusions about some of the
reports are limited, since pulmonary function was not measured
nor was the presence of GER confirmed objectively either pre or
post operatively.
4
There are reasons why the antireflux therapy studies may have
failed to show more impressive effects on asthma control. Asth-
matics have different sensitivities to different triggers.
13
Some
respond to certain allergens or to exercise whereas others do not.
The inclusion of asthma patients who are insensitive to GER in
study cohorts might mask a potential benefit. Continuing asthma
medications during the antireflux therapy trials may have blunted
potential changes due to GER. Many asthma patients have normal
or near normal lung function between asthma attacks and antire-
flux therapy would not be expected to improve pulmonary function
indices. There are also statistical factors to consider. Generally the
sample sizes in the studies were small and type two error cannot be
excluded.
3
Both medical and surgical antireflux therapies have a role in
asthma patients with symptomatic GER that requires therapy. The
evidence does not support the notion that fundoplication is supe-
rior to medical antireflux therapy for asthma control.
3,4
Currently,
there is no evidence for a role for treating asymptomatic GER in
asthma. Although unproven, there may be a minority of patients
with difficult-to-control asthma who would benefit from antireflux
therapy.
Other more common causes of poor asthma control such as
ongoing exposure to allergens or cigarette smoke, inadequate
antiinflammatory therapy, improper inhaler use, and noncompli-
ance to prescribed drug regimens need to be excluded in patients
with difficult-to-control-asthma. Other conditions that can mas-
querade as poorly controlled asthma such as vocal cord dysfunc-
tion also have to be excluded.
In summary, I believe that it is premature to recommend fun-
doplication as the preferred option for asthma control in asthmatics
with GER. Further properly powered, controlled trials are needed
to understand the relationship between GER and asthma, and the
roles of proton pump inhibitors and fundoplication in these
patients.
STEPHEN K. FIELD, MD, CM, FRCPC
Clinical professor
Division of Respiratory Medicine
University of Calgary Medical School
References
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ANNALS OF SURGERY
Vol. 234, No. 1, 130–134
© 2001 Lippincott Williams & Wilkins, Inc.
LETTERS TO THE EDITOR
130