Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
0161-4754/2001/$35.00 + 0 76/1/116417 © 2001 JMPT
ORIGINAL ARTICLES
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation: A Prospective Clinical Series and
Randomized Clinical Pilot Study
Gert Bronfort, DC, PhD,a Roni L. Evans, DC,a Paul Kubic, MD, PhD,b and Patty Filkinb
ABSTRACT
Objectives: The first objective was to determine if chiropractic spinal manipulative therapy (SMT) in addition to optimal medical
management resulted in clinically important
changes in asthma-related outcomes in children. The second objective was to assess the
feasibility of conducting a full-scale, randomized clinical trial in terms of recruitment, evaluation, treatment, and ability to deliver a sham SMT
procedure.
Study Design: Prospective clinical case series combined with
an observer-blinded, pilot randomized clinical trial with a 1year follow-up period.
Setting: Primary contact, college outpatient clinic, and a pediatric hospital.
Patients: A total of 36 patients aged 6 to 17 years with mild
and moderate persistent asthma were admitted to the study.
Outcome Measures: Pulmonary function tests; patient- and parent- or guardian-rated asthma-specific quality of life, asthma
severity, and improvement; AM and PM peak expiratory flow
rates; and diary-based day and nighttime symptoms.
Interventions: Twenty chiropractic treatment sessions were
scheduled during the 3-month intervention phase. Patients were
randomly assigned to receive either active SMT or sham SMT
in addition to their standardized ongoing medical management.
Results: It is possible to blind the participants to the nature of the
SMT intervention, and a full-scale trial with the described design
is feasible to conduct. At the end of the 12-week intervention
phase, objective lung function tests and patient-rated day and
INTRODUCTION
Asthma is a multifactorial condition and the most common chronic disease of childhood.1 Since 1980, the prevalence of pediatric asthma has increased more than 50% and
a
Wolfe-Harris Center for Clinical Studies, Northwestern Health
Sciences University, Bloomington, Minn.
b
Children’s Health Care, St Paul, Minn.
This study was funded by the Foundation for Chiropractic
Education and Research.
Gert Bronfort, DC, PhD, holds the Greenawalt Research Chair,
funded through an unrestricted grant from Foot Levelers, Inc.
Submit reprint requests to: Gert Bronfort, DC, PhD, WolfeHarris Center for Clinical Studies, Northwestern Health Sciences
University, 2501 West 84th Street, Bloomington, MN 55431.
Paper submitted June 5, 2000; in revised form September 5,
2000.
doi:10.1067/mmt.2001.116417
nighttime symptoms based on diary recordings showed little or no change. Of the
patient-rated measures, a reduction of approximately 20% in β2 bronchodilator use
was seen (P = .10). The quality of life scores
improved by 10% to 28% (P < .01), with the
activity scale showing the most change.
Asthma severity ratings showed a reduction of
39% (P < .001), and there was an overall improvement rating corresponding to 50% to 75%.
The pulmonologist-rated improvement was small.
Similarly, the improvements in parent- or guardian-rated outcomes were mostly small and not statistically significant. The
changes in patient-rated severity and the improvement rating
remained unchanged at 12-month posttreatment follow-up as
assessed by a brief postal questionnaire.
Conclusion: After 3 months of combining chiropractic SMT with
optimal medical management for pediatric asthma, the children
rated their quality of life substantially higher and their asthma
severity substantially lower. These improvements were maintained
at the 1-year follow-up assessment. There were no important
changes in lung function or hyperresponsiveness at any time. The
observed improvements are unlikely as a result of the specific
effects of chiropractic SMT alone, but other aspects of the clinical
encounter that should not be dismissed readily. Further research is
needed to assess which components of the chiropractic encounter
are responsible for important improvements in patient-oriented outcomes so that they may be incorporated into the care of all patients
with asthma. (J Manipulative Physiol Ther 2001;24:369-77)
Key Indexing Terms: Asthma; Pilot Projects; Feasibility Studies;
Chiropractic Manipulation; Pediatric; Placebo
mortality more than 70%.2 The management of asthma has
changed substantially since the early 1990s, and national
and international guidelines now recommend a stepwise
approach to treatment.3 Fundamental to current management is the early introduction of antiinflammatory medication rather than reliance on bronchodilators. Inhaled steroids
suppress the inflammation of asthma and effectively control
symptoms in most patients. By contrast, inhaled β2-agonists
relieve symptoms for a short-term period but do not control
the underlying inflammation. Indeed, it has been questioned
whether excessive use of inhaled β2-agonists may contribute
to the increased morbidity and mortality of the condition.4
Alternative and complementary treatments are commonly
used by the general population.5 The dependence on medication and the uncertainty about outgrowing the disease lead
many parents of children with asthma to seek these types of
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Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
treatments.6-9 There is some evidence from randomized clinical trials (RCT) that acupuncture, yoga, suggestion, hypnosis, massage, and relaxation can be beneficial as adjunctive
measures in the management of chronic asthma.6-7
Studies indicate that it is not uncommon for patients with
breathing difficulties such as asthma to receive chiropractic
care. According to a Danish survey,10 a substantial number
of children with chronic asthma receive chiropractic care,
and 92% of parents consider this treatment beneficial. A
1998 report of an Australian survey estimated that 1% to
10% of children with asthma receive chiropractic treatment
for this condition.9
Several descriptive studies and anecdotal reports in the
literature claim positive clinical effect of manual spinal
therapy for lung dysfunction and asthma.11-14 A few clinical studies have also addressed the role of spinal manipulative therapy (SMT) in obstructive bronchial disorders.15,16
Increases in vital capacity, total lung capacity, and forced
expiratory volume in chronic obstructive pulmonary disease were reported in a controlled trial on the effectiveness of spinal manipulation.15 These improvements were
greater than in a control group, although statistical significance was not reached. A preliminary study by Hviid16
showed that chiropractic SMT seemed to improve vital
capacity, peak expiratory flow rate, and subjective symptoms in a group of patients with various types of obstructive lung disease. Unfortunately, the small sample size did
not allow for definitive conclusions. A pilot study17 of asthmatic patients in a chiropractic clinic found that although chiropractic SMT did not reduce airway obstruction, patients
reported subjective reduction in their asthma symptoms.
At the time the current study was initiated, only one RCT
had assessed the effectiveness of SMT for patients with
asthma.18 The crossover trial by Nielsen et al18 was performed on adult patients and found no clinically important
change in pulmonary function. A reduction in patient-rated
asthma severity and hyperresponsiveness was observed;
however, there were no differences between the active and
sham SMT phases.
In 1993, the authors proposed a prospective case series
and pilot study with two objectives. The first was to determine if chiropractic SMT in addition to optimal medical
management resulted in clinically important changes in asthma-related outcomes. The second objective was to assess the
feasibility of conducting a full-scale RCT in terms of recruitment, evaluation, treatment, and ability to deliver a sham
SMT procedure.
METHODS
Study Sites
This study was conducted at the Wolfe-Harris Center for
Clinical Studies at Northwestern College of Chiropractic,
Bloomington, Minn, and Children’s Health Care, St Paul,
Minn (formerly Children’s Hospital). The study was approved by the institutional review boards of both institutions, and informed consent was sought from all study participants and their parents or guardians.
Recruitment
Patients were recruited through a pediatric pulmonary
practice at Children’s Health Care and through newspaper
advertising.
Inclusion and Exclusion Criteria
Patients were required to attend 4 baseline appointments
during an 8-week period to determine eligibility. Patients
were eligible for the study if they were aged 6 to 17 years
and had mild or moderate persistent asthma as diagnosed by
the pediatric pulmonologist using national guideline criteria.3 Mild persistent asthma was defined as the presence of
symptoms more than twice a week but less than once a day,
exacerbations that may affect activity, presence of nighttime
symptoms more than twice a month, forced expiratory volume in the first second (FEV1) or peak expiratory flow
(PEF) ≥ 80% of predicted, and PEF variability of 20% to
30%. Moderate persistent asthma was defined as the presence of daily symptoms, exacerbations 2 or more times a
week, exacerbations that may affect activity, presence of
nighttime symptoms more than once a week, FEV1 or PEF
60% to 80% of predicted, and PEF variability >30%. Patients were also required to have the presence of spinal dysfunction as determined by a chiropractic physician. Patients
were excluded from study participation if they had any of
the following: other clinically important medical diseases,
obstruction of large or small airways from conditions other
than asthma, previous chiropractic SMT, any contraindications to manual SMT, oral steroid therapy exceeding 30
days during the past year, abnormal chest radiographs, and
concurrent immunotherapy.
Randomization
The randomization schedule was computer-generated.
The allocation ratio was 2:1 so that the number of patients in
the active SMT group was twice the number in the sham
SMT group. Stratification by age (5 to 12 years and 13 to 17
years) was performed with permuted block randomization
to ensure equal numbers of participants in each age group.
Each treatment allocation was placed in a sealed, opaque
envelope and was opened by treating clinicians at the end of
the fourth baseline visit once eligibility had been confirmed.
Treating clinicians were blinded to upcoming treatment
assignments and remained unaware of the block size.
Interventions
All patients were medically managed throughout the study.
The medical treatment followed the standardized guidelines
for the management of chronic asthma in children.3 Both
mild and moderate persistent asthmatic patients were prescribed maintenance or controlling therapy as well as β2agonists on an as-needed basis for symptom relief, not to
exceed 3 to 4 times a day. The maintenance therapy included several drug options. For mild persistent asthma, daily
antiinflammatory medication was used in the form of inhaled corticosteroids in low dose or cromolyn sodium or
occasionally sustained-released theophylline. For moderate
Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
persistent asthma, the daily antiinflammatory medication
was inhaled corticosteroids in higher dose or cromolyn sodium or occasionally sustained-released theophylline, and
often long-acting β2-agonists either inhaled or in tablet
form. During exacerbations lasting for several days, short
courses of systemic corticosteroid therapy were used. For
both types of patients with asthma, antiallergic medications
were used when indicated during allergy seasons.
Chiropractic treatment. One licensed, experienced chiropractor delivered both active and sham treatments in the study.
Care was taken to spend the same amount of time with all
patients. A total of 20 treatment sessions were scheduled for
each patient during the 3-month intervention phase.
Spinal manipulation. Manipulation of dysfunctional joints of
the spine and pelvis was carried out with the patient placed
on a chiropractic treatment table with separate cushion sections for the cervical, thoracic, and lumbar spine. Drop mechanisms are built into these sections, enabling them to be
quickly released and lowered 2 to 3 cm when the force from
the manual treatment exceeds a certain preset level according to the weight of the patient. This technique is used to
facilitate and accentuate the specific manual treatment. The
manual spinal thrusting technique used a specific contact
over a vertebral osseous process, muscle, or ligament and
introduced a force into the selected vertebral or sacroiliac
joint. This manual spinal treatment was carried out with a
high-velocity, low-amplitude thrust, most commonly by
means of a short-lever technique.
Sham spinal manipulation. Patients in the sham manipulation
group received light manual contact to the spine with no
manipulative thrust. For this procedure, a treatment table
with releasable drop sections was also used. The patient was
first placed prone for the thoracic and lumbar spine contacts
and then on his or her side for the cervical spine contact. The
sham treatment consisted of gentle manual pressure over a
spinal contact point with one hand, while the other hand
pushed on the drop section with the purpose of releasing it.
The tension of the drop section was set just great enough not
to be released by the weight of the patient. As a result of this
procedure, the patient experienced a rapid, momentary
change in position of the spinal section under influence,
similar to an active treatment. Similar manual maneuvers
have been used in previous studies and have been shown to
be acceptable placebo treatments.
Outcome Measures
Evaluation of pulmonary function. Certified pulmonary technicians at the participating hospital’s respiratory laboratory
performed pulmonary function tests. These results were
measured at baseline and after 12 weeks of treatment.
Tests included spirometry, forced volume loop, lung volume, plethysmography, and nonspecific bronchial challenge
with exercise challenge. Spirometry and forced volume
studies were performed with a pneumotachometer, its signal
integrated with a computerized pulmonary function test system. The lung function measurements were conducted at
approximately the same time of day. The mean of two
repeated measurements was used for calculation. The following protocol was administered for withdrawal of medication before lung function tests and nonspecific bronchial
challenges: oral β2-agonists for 24 hours, inhaled bronchodilators for 6 hours, and antihistamines and long-acting
theophylline for 48 hours. The pulmonary technicians were
blinded to the treatment allocation of the patients.
Diaries and peak expiratory flow rate. Patients were given an asthma diary at the first baseline visit and were instructed on how
to perform daily peak expiratory flow readings (PEFR) with
the Truzone peak flow meter (Monaghan Medical Corporation). Patients were asked to record day and nighttime peak
flow and symptoms and daily β2 inhaler use for the entire 12week treatment period. Compliance with filling out the diary
and peak flow meter technique was checked periodically.
Questionnaires. Questionnaires assessing quality of life and
asthma severity and improvement were administered twice
at baseline and after 12 weeks of treatment. A postal questionnaire assessing asthma severity and improvement was
administered 1 year after the end of treatment. Patient-rated,
asthma-specific quality of life was measured by an interviewer-administered questionnaire developed by Juniper et
al.19 Parent-/guardian-rated quality of life was measured by
a self-report questionnaire developed by the same investigators.20 Patient-rated and parent-/guardian-rated asthma
severity and improvement were also measured with selfreport questionnaires. Severity was assessed with an 11-box
scale,21 where 0 = no symptoms and 10 = worst symptoms
possible. Improvement was measured with a 9-point scale
ranging from “no symptoms: 100% better” to symptoms
“twice as bad: 100% worse.” Patients, parents/guardians,
and interviewers were all blinded to the patients’ treatment
assignment.
Success of patient blinding. After the end of the 12 weeks of
treatment, patients and their parents/guardians were asked
to indicate which treatment group they thought patients had
received.
Statistical Analyses
Based on sample size calculations, 20 patients were required in the active treatment group, which constituted the
prospective case series, to detect a 15% to 25% change in
most of the outcome measures. Ten patients were determined
sufficient for the sham treatment group to assess the feasibility of delivering a sham procedure. Allowing for a 20%
dropout rate, 36 patients were needed for the study. Statistical analyses of data from patients in the active treatment
group included paired Student t tests comparing baseline
values with posttreatment values at 12 weeks. P values < .01
were considered statistically significant for the 5 main outcome variables: morning and evening PEFR, patient-rated
asthma severity, as-needed β2 bronchodilator use, and airway responsiveness. Confidence intervals of 95% were calculated for change scores in FEV1, FEF25-75, general health
status, symptoms, and asthma-specific quality of life (patientand parent-/guardian-rated). Diary data from the 2 weeks
before randomization and the 11th and 12th weeks after
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Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
Table 1. Baseline demographic and clinical characteristics (means and SD unless otherwise noted)
Characteristic
Age (SD) (y)
Age ≤ 12 (y) (%)
Male child (%)
Moderate persistent asthma (%)
Mild persistent asthma (%)
Patient-rated
Asthma severity (0-10)
Quality of life (1-7)*
Symptoms
Activity
Emotions
Overall score
Parent-/guardian-rated
Asthma severity (0-10)
Quality of life (1-7)*
Activity
Emotions
Overall score
FEV1 % predicted
FVC % predicted
FEV1/FVC
FEF25-75 predicted
PEFR AM L/min
PEFR PM L/min
Diary scores (0-4)
Wheezing
Shortness of breath
Coughing
Disturbed sleep
Feeling of panic
Restricted activity
β2-agonist use: no. of puffs/d
Age when diagnosed with asthma (y)
Age when asthma symptoms started (y)
Active SMT
(n = 22)
Sham SMT
(n = 12)
10.4 (3.1)
16 (73)
13 (59)
14 (64)
8 (36)
10.6 (3.1)
8 (67)
6 (50)
10 (83)
2 (17)
3.6 (1.5)
2.4 (2.6)
5.3 (1.1)
4.6 (1.1)
6.0 (0.7)
5.0 (0.8)
6.0 (0.9)
5.5 (1.3)
6.3 (1.1)
5.9 (1.1)
2.5 (1.9)
2.4 (2.7)
6.0 (1.2)
5.8 (0.9)
5.9 (1.0)
93.0 (12.4)
104.1 (11.7)
81.4 (7.5)
77.0 (25.0)
285.4 (102.0)
288.4 (105.3)
6.4 (1.3)
5.7 (1.6)
6.0 (1.4)
93.2 (9.6)
109.7 (12.5)
78.4 (7.0)
70.9 (14.8)
286.3 (104.0)
292.6 (106.3)
0.3 (0.4)
0.6 (0.6)
0.7 (0.7)
0.2 (0.4)
0.1 (0.2)
0.3 (0.5)
2.0 (1.5)
4.9 (3.4)
2.8 (3.1)
0.4 (0.5)
0.6 (0.6)
0.7 (0.5)
0.1 (0.2)
0 (0.0)
0.2 (0.5)
1.4 (1.3)
6.5 (3.9)
5.4 (4.2)
FEV1, Forced expiratory volume in 1 second; FVC, forced vital capacity; FEF25-75, forced expiratory flow 25% to 75%; PEFR, peak expiratory flow rate.
*Quality of life scores range from 1 (maximal impairment) to 7 (no impairment).
treatment were used for the analyses. At no time were comparisons made between the active and sham treatment groups
because of the high risk of committing type I and II errors.
RESULTS
The pilot study took place from May 1996 to August
1998. Flow of study participants is outlined in Fig 1. A total of
96 patients were screened by telephone, with 46 patients
undergoing baseline evaluations. Of the 46 patients evaluated, 10 did not qualify for inclusion. Of these, 6 patients decided they could not commit the time and effort, 3 had intermittent asthma, and 1 had severe asthma. Thirty-six qualified
patients were randomly assigned to treatment, 24 to the
active SMT group and 12 to the sham SMT group. Two patients randomly assigned to the active SMT group dropped out
of the study before starting treatment as a result of serious illness in the family. The 2 patients had clinical and demographic
characteristics similar to the rest of the patients in that group.
Most of the children were classified as having moderate
persistent asthma. The active and sham groups were dissimilar at baseline, especially in terms of classification and
patient-rated severity. No attempts were made to perform
statistical comparisons between the 2 groups. The important
demographic and clinical characteristics are summarized in
Table 1. The patients in the active SMT group received a
mean of 19.6 treatment sessions, and the patients in the
sham SMT group received an average of 19.3 treatment sessions. At the end of the 12-week intervention phase, the
active SMT group showed little or no change in objective
lung function tests (Table 2) and patient- and parent-/guardianrated day and nighttime symptoms (Table 3). Table 4 illustrates the patient-, parent-/guardian-, and pulmonologistrated asthma improvement at 12 weeks.
Of the patient-rated measures, a reduction of approximately 20% in β2-bronchodilator use was observed (P =
.10). The quality of life scores improved 10% to 28% (P <
.01), with the activity scale showing the most change. The
severity rating showed a reduction of 39% (P < .001), and
there was an overall improvement rating corresponding to
50% to 75%. The pulmonologist-rated improvement was
small. Similarly, the improvements in parent-/guardianrated outcomes were mostly small and not statistically significant. The changes in patient-rated severity and patientrated improvement remained unchanged at 12-month
posttreatment follow-up assessment. The belief that active
treatment was given was similar in both groups. At the end
of the treatment phase, 64% of the children and parents or
guardians in the sham group and 73% of the children and
parents or guardians in the active group guessed that they
were allocated to the active treatment group (Table 5).
Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
Table 2. Change in pulmonary lung function tests in active SMT group: week 12 values in percent of baseline values
Parameter
Morning PEFR
Evening PEFR
FEV1
FVC
FEV1/FVC
FEF25-75
Bronchial challenge test (hyper-responsiveness)
FEV1 5 min after exercise
FEV1 15 min after exercise
FEF25-75 5 min after exercise
FEF25-75 15 min after exercise
Body plethysmography
TGV
RV
TLC
RAW
GAW
SGAW
IgE
n
Mean %
19
19
22
18
22
22
98.8
101.7
105.7
104.3
99.9
107.6
94.4 to 103.3
94.8 to 108.5
102.4 to 109.0
101.6 to 107.1
97.2 to 102.7
98.2 to 116.9
95% CI
22
22
19
22
112.6
104.1
113.0
103.6
97.5 to 127.6
99.8 to 108.4
81.3 to 144.6
92.7 to 114.5
12
12
12
12
12
12
15
101.9
96.1
100.6
86.8
162.7
137.4
109.6
92.7 to 111.0
74.5 to 117.7
95.2 to 106.1
58.6 to 115.0
86.0 to 239.4
95.5 to 179.2
70.4 to 148.8
PEFR, Peak expiratory flow reading; TGV, thoracic gas volume; RV, residual volume; TLC, total lung capacity; RAW, airway resistance; GAW, airway
conduction; SGAW, specific airway conduction; IgE, immune-gammaglobulin E; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity;
FEF25-75, forced expiratory flow 25% to 75%.
DISCUSSION
The Medical Expenditure Panel Survey estimated that
almost 7% of the United States population sought unconventional health care in addition to conventional medical care in
1996.5 The most common of the unconventional therapies
was chiropractic care. Parents frequently seek care for their
asthmatic children from chiropractors; however, there has
been little scientific evidence to support such practices. Our
study was an initial step in evaluating the scientific evidence
of chiropractic spinal manipulation for children with asthma.
We considered it important to perform a pilot study
combined with a prospective case series before embarking
on a full-scale trial. First, if clinically important changes
were not observed prospectively in either lung function,
asthma severity, day and nighttime symptoms, or asthma
specific quality of life, we had decided a priori not to
conduct a full-scale clinical trial with this study design.
Second, we believed it was necessary to determine the
study feasibility before undertaking a costly and timeconsuming full-scale, randomized clinical trial. Could
patients be recruited in sufficient numbers to ensure adequate statistical power? What were the most cost-efficient
methods of recruitment? Would patients and providers
comply with study protocols? Could a sham SMT procedure be effectively delivered? We did establish that it is
feasible to conduct a full-scale trial, although recruitment
was slow and difficult. Patients and providers complied
well with our protocols, and it appeared that patients and
guardians were successfully blinded to the chiropractic
treatment and had similar experiences of overall satisfaction regardless of group allocation.
The prospective case series part of this study demonstrated that after 12 weeks of SMT combined with optimal
medical management, there were no clinically important
changes in pulmonary lung function (PEFRs, FEV1, forced
Fig 1. Flow of participants.
expiratory flow 25% to 75%, and hyperresponsiveness),
patient-rated day and nighttime symptoms, and parent-/
guardian-rated assessment of the child’s quality of life and
asthma severity. However, clinically important changes were
found in patient-rated quality of life (particularly the activity domain) and patient-rated asthma severity and improvement. The discrepancy between child and parent/guardian ratings is consistent with those reported by other investigators.22
A study of similar design with a larger sample size was
recently reported by Balon et al.23 When we compare our
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Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
Table 3. Patient- and parent-/guardian-rated outcomes at week 12 in active SMT group: change from baseline
Parameter
Patient-rated
Severity (0-10)
Quality of life
Symptoms
Activity
Emotions
Overall score
Diary scores (0-4)
Wheezing
Shortness of breath
Coughing
Disturbed sleep
Feeling of panic
Restricted activity
β2-agonist use (no. of puffs/day)
Parent-/guardian-rated
Severity (0-10)
Quality of life
Activity
Emotions
Overall score
Table 4. Patient-, parent-/guardian-, and pulmonologist-rated
improvement in asthma at week 12 in active SMT group (n = 22)
Improvement in asthma (1-9)*
Patient-related
Parent-/guardian-rated
Pulmonologist-related
Mean
95% CI
2.5
3.0
4.3
2.0 to 2.9
2.6 to 3.5
3.8 to 4.9
*1, No symptoms; 2, much better; 3, somewhat better; 4, a little better; 5, no
change; 6, a little worse; 7, somewhat worse; 8, much worse; 9, twice as bad.
results with the Balon et al trial, we note that similar and
clinically important changes in asthma-specific quality of
life and severity were found in both studies in the active
SMT groups. However, the Balon et al study showed that
these changes occurred in the sham SMT group as well.
Although the improvements tended to be greater in the
active group in most of the quality of life domains, they
found no clinically important or statistically significant differences between active and sham SMT. There were no clinically important changes in lung function and airway hyperresponsiveness in either study. Patients in both studies had
either chronic mild or moderate persistent asthma, but because they were optimally medically managed, their asthma
was “under control.” In terms of lung function, there was
therefore not much room for improvement, although we
would expect a reduction in β2-agonist use to accompany
any reduction in patient-rated asthma severity. There was
also a similar decline in β2-agonist use in both studies.
Again, this reduction in the Balon et al23 study was of equal
magnitude in both the active and the sham SMT groups.
What then are likely explanations for the patient-rated
improvements in quality of life and patient-rated asthma
severity? Recent research has shown that physical treatments such as massage appear to be beneficial in the management of children with pulmonary dysfunction and chronic asthma.24 An RCT by Field et al25 found that children
n
Week 12 (change from baseline)
95% CI
20
–1.4
–2.0 to -0.8
22
22
22
22
0.6
1.3
0.5
0.8
0.3 to 0.9
0.8 to 1.8
0.2 to 0.8
0.5 to 1.1
17
17
17
17
17
17
17
0.1
0
–0.1
–0.1
0
–0.1
–0.5
–0.1 to 0.3
–0.2 to 0.2
–0.5 to 0.4
–0.3 to 0.2
–0.1 to 0.1
–0.2 to 0.1
–1.5 to 0.4
22
–0.1
–1.2 to 0.9
22
22
22
0.6
0.4
0.5
0 to 1.2
0 to 0.8
0.1 to 0.9
who received 1 month of daily massage therapy by their parents showed decreased behavioral anxiety and increased
cortisol levels. Thus it is possible that the physical contact involved in the spinal manipulation and the accompanying soft
tissue palpation and massage used in the chiropractic studies
may explain some of the benefits observed in our study.
Patient education is another important part of the successful management of asthma. It is important for patients to
understand their asthma, recognize its triggers, and learn to
practice necessary management skills. Family support is
essential in their efforts. It has been shown that patients and
parents/guardians are better able to focus on clinicians’ recommendations after major concerns and fears have been
addressed.26,27 Sometimes psychosocial dysfunction in the
family may have a negative impact on the child with asthma.27,28 A recent systematic review concluded that family
therapy for pediatric asthma appeared to reduce the severity
of asthma and improve lung function, and it may be a useful
adjunct to medication therapy.29 In our study, a substantial
amount of time was spent educating parents and children on
how to recognize and rate their asthma symptoms and how
to perform peak flow measurements, assess readings, and
use β2-agonists appropriately. The increased sense of control and knowledge about the asthmatic condition is likely to
have resulted in anxiety reduction, contributed to proper
medication use, and thus may also explain some of the
observed improvement in outcomes.
The daily use of asthma diaries might in itself account for
improvement in both the active and sham SMT groups. A
recent randomized trial showed that by having asthma
patients write about stressful life events, pulmonary lung
function was increased. 30 It is possible that by having
patients in our study subjectively evaluate and rate their
asthma symptoms, this expression of their asthma-related
stressful events resulted in increased asthma-related quality
of life.
Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
Table 5. Assessment of treatment blinding
Treatment assessment
Correctly guessed treatment allocation at week 12
Incorrectly guessed treatment allocation at week 12
Overall patient/parent/guardian satisfaction*
Placebo
treatment
(n = 11)
Chiropractic
treatment
(n = 22)
4
7
1.0 (0.0)
16
6
1.4 (0.9)
1, Excellent; 2, very good; 3, good; 4, fair; 5, poor.
*Means and SD.
The frequency of care and the subsequent social connection that likely developed between the chiropractor and
patients also deserves comment. Several studies have indicated that increased socialization is associated with positive
health outcomes,31 and this too may account for some of the
improvements noted in this study.
Overall, our study corroborates the findings of the Balon
et al23 and Nielsen et al18 studies; collectively, the studies
suggest that factors other than the specific effects of SMT
are contributing to most of the changes in quality of life and
patient-rated asthma severity and improvement observed in
these studies. If these factors are mainly nonspecific or placebo effects, what does this mean to patients, clinicians, and
policy makers in considering the use of chiropractic care in
the management of asthma?
The placebo or nonspecific treatment effect has traditionally been regarded as a confounding or nuisance factor to be
controlled for or eliminated. However, this nonspecific
effect is an important and often powerful aspect of any therapy,32 and depending on the patient’s experience with the
therapeutic encounter, it may potentiate the patient’s own
healing capacity to different degrees. There is some evidence to suggest that this effect may be mediated by the
brain through neural endocrine influences capable of modulating the function of the immune system.33 The theory that
the brain is capable of influencing the immune system has
been confirmed in several RCTs, which used interventions
such as suggestion, self-hypnosis, imagery, and relaxation
techniques.34 The nonspecific therapeutic effect has several
known and likely several unrecognized dimensions. In the
context of a clinical trial, the manner in which the informed
consent is given, the expectations of the patient, and the
enthusiasm and the attention of the treatment provider are
factors that can have an impact on the patient-experienced
outcome. It has been shown in practice-based studies that
the doctor’s attitude toward therapy, whether positive or
negative and either with or without confidence, has an influence on the outcome of treatment.35
It has been argued that it is unreasonable to discard a therapy or consider it worthless if it is only a little better or even
no better than a suitable placebo. What matters is the magnitude of effect on patients’ outcomes when compared with
commonly used treatments and in particular, no-treatment
controls, if a patient wishes to decide more rationally which
interventions a health care service should pay for.36 Two
placebo-controlled trials examining the effect of adding chi-
ropractic spinal manipulation to the optimal medical management of chronic asthma in either children or adults showed
no important difference between the active and placebo
arms.18,23 However, in both trials a clinically important
improvement in asthma-related quality of life and a reduction in patient-reported asthma severity appeared to result in
both active and sham SMT groups. These improvements are
unlikely to occur solely as a result of the natural history or
regression to the mean. On that basis, it may not be appropriate to deem the addition of chiropractic care to medical
management worthless and to proscribe its use.
Limitations
When interpreting the findings of our prospective clinical series, it is impossible to make any causal inferences.
The improvements observed in patient-oriented outcomes
may be the result of a multitude of factors. Considering
the chronicity of the disorder, the changes were unlikely
the result of natural history. Some of the changes may be
explained by regression to the mean because patients often enroll in studies when their symptoms are most severe.
However, in this study patients went through a 2-month
baseline period during which time their medical management was optimized. Changes in outcomes were measured
from the end of this baseline period. In addition, it is possible that the specific effect of spinal manipulation may
have been masked by the effect of the medications.
Ethical considerations prevent the assessment of spinal
manipulation alone in mild to moderate asthmatics.
However, it is possible to design a study in which patients
are given spinal manipulation in addition to medication
and then monitored to see if medications can be reduced.
According to the most recent guidelines, such a “step
down” in medication should not be considered until the
asthmatic condition has remained stable and has improved
for at least 3 months. Thus for this to be assessed adequately, patients should be managed for longer periods to
see if the reduction in medications can occur and if so, be
maintained.
Another consideration is that during the study period,
almost half the children had upper respiratory infections.
These children had substantially poorer outcomes compared
with the children who did not have upper respiratory infections. Upper respiratory infections are extremely common
in children with asthma and tend to mask improvement from
ongoing therapy. Finally, it is possible that the SMT may
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Journal of Manipulative and Physiological Therapeutics
Volume 24 • Number 6 • July/August 2001
Chronic Pediatric Asthma and Chiropractic Spinal Manipulation • Bronfort et al
have specific effects in only certain subgroups of patients,
which we were unable to identify in our study given the relatively small sample.
Future Research
One of the strengths of this study is that it reflects to a certain extent what is occurring in health care today. Substantial
numbers of patients are seeking “unconventional” health
care in addition to medical care rather than as a replacement
for it.5 Future studies should continue to assess the multidisciplinary comanagement of asthma to enhance study generalizability and even more importantly, to optimize patient
care. We submit that future studies should focus their attention on assessing what aspects of the chiropractic clinical
encounter are responsible for the improvement in important
patient-rated outcomes observed in the studies performed to
date. Is it the touch and attention? Is it the relaxation that
may ensue from the physical nature of the chiropractic interventions? Maybe it is the filling out of diaries, the continuous
monitoring, or increased patient focus on their condition,
resulting in a better compliance, decreased anxiety, and
appropriate use of prophylactic and abortive medications. It
is possible still even in the light of the current scientific evidence that spinal manipulation does have worthwhile specific effects in certain patient populations. Likely, it is a combination of some or all of these factors. In any case, something
is occurring that makes the patients feel better, as indicated
by changes in well-recognized measures of quality of life.19
For this reason alone, future exploration is warranted. In
addition, studies with larger sample sizes will be necessary
to identify if worthwhile specific effects can be demonstrated
in subgroups of patients.
The personal dimension of the clinical encounter offers
a rich potential for useful interventions.37 The generic elements of empathy and verbal and nonverbal communication (including listening and touch) need to be explored.
The complexity of the physical, psychologic, and sociologic components of the chiropractic clinical encounter
must be acknowledged, and it is likely that new methods
for assessing these complex effects will need to be developed.37
CONCLUSION
After 3 months of combining chiropractic SMT with optimal medical management for pediatric asthma, the children
rated their quality of life substantially higher and their asthma severity substantially lower. These improvements were
maintained at the 1-year follow-up assessment. There were
no important changes in lung function or hyperresponsiveness at any time. The observed improvements are unlikely to
be the result of the specific effects of chiropractic SMT, but
other aspects of the clinical encounter that should not be
readily dismissed. Further research is needed to assess
which components of the chiropractic encounter are responsible for important improvements in patient-oriented outcomes so that they may be incorporated into the care of all
asthmatic patients.
ACKNOWLEDGMENTS
We thank Jennifer Hart for assistance with manuscript
preparation and the staff of the Wolfe-Harris Center for
Clinical Studies and Children’s Health Care for their assistance with evaluation and treatment appointments. Finally, we
thank the children and their guardians for devoting their time
to this project and teaching us more about pediatric asthma.
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CORRECTION
In a correction listed on page 355 of the June 2001 issue, an author’s name
was misspelled. The correct title and authors should read as follows: “Prognostic
Values of Physical Examination Findings in Patients with Chronic Low Back
Pain Treated Conservatively: A Systematic Literature Review” by Borge JA,
Leboeuf-Yde C, and Lothe J (2001;24:292-5).
We apologize for the error and regret any confusion it may have caused.
377