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OJHAS Vol. 10, Issue 2:
(Apr-Jun 2011) |
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| Comparison of Subjective and Objective Physical Functions in Patients with Chronic Low Back Pain |
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Agwubike
EO, Department of Health,
Environmental Education and Human Kinetics, Faculty
of Education, University
of Benin, Benin
City, Nigeria,
Ezeukwu AO, Department
of Medical Rehabilitation, Faculty
of Health Sciences & Technology, University
of Nigeria, Enugu
Campus, Nigeria. |
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Address for Correspondence |
Department of Medical Rehabilitation,
Faculty of Health Sciences
& Technology,
University of Nigeria,
Enugu Campus, Nigeria.
E-mail:
leo_ninus@yahoo.com |
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Agwubike
EO, Ezeukwu AO. Comparison of Subjective and Objective Physical Functions in Patients with Chronic Low Back Pain. Online J Health Allied Scs.
2011;10(2):13 |
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Submitted: June 22,
2011; Accepted: Jul 18, 2011; Published: Jul 30, 2011 |
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| Abstract: |
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Purpose:
To compare the subjective and objective physical function scores of
patients with Chronic Low Back Pain (CLBP). Method:
A cross- sectional survey design was used. Fifty-one patients with CLBP of mechanical origin were recruited from the physiotherapy out
patient clinics of the University of Nigeria Teaching Hospital and the
National Orthopedic Hospital both in Enugu, Nigeria. The box numerical
scale, Roland-Morris Questionnaire (RMQ-24) and the Back Performance
Scale (BPS) were used to assess the present pain intensity, the subjective
and objective functional status of the participants respectively. Pearson
correlation was used to determine relationships. Multiple Regressions
were used to determine the predictors of objective function. Alpha level
was set at 0.5. Results:
The mean age and Body Mass Index of the participants were 49.04 ± 14.33
years and 26.57 ± 4.29 kg/m2 respectively. The mean Pain
Intensity, subjective disability (RMQ) and objective disability (BPS)
scores were 6.33 ± 2.09, 9.76 ± 5.14 and 6.43 ± 2.9 respectively.
Stepwise multiple regressions showed that when all the variables were
entered only marital status was a significant predictor of objective
physical function. Conclusion:
There is no significant association between subjective and objective
functions in patients with CLBP. However, marital status (married) is
a significant predictor of objective function in CLBP.
Key Words:
Objective; subjective; Chronic low back pain; Roland-Morris; Back Performance
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It is not new to science that human beings have adapted a bipedal position.
However, this adaptation comes with its myriad of musculoskeletal health
problems and challenges, among which is Low Back Pain (LBP). LBP is
defined as pain between the costal margins and the inferior gluteal
folds.1 It is said to be chronic when the pain is intermittent
or persistent for greater than or equal to three consecutive months
within twelve months.2-5 It is ubiquitous to every population
no matter the level of technological or industrial advancement. In recent
times, its incidence and prevalence are on the increase, thus necessitating
closer attention. Hence, clinicians are constantly grabbling with how
best to evaluate this clinical syndrome.6
Physical Function (PF) is defined as the senseriomotor performance of
an individual that includes fundamental and complex Activities of Daily
Living (ADL)7, and patients with Chronic Low Back Pain (CLBP)
frequently report of reduced PF.8,9 Rehabilitation specialists,
Physiotherapists and Exercise scientists are recently engaging in the
clinical application of evidence based research in the management of
patients with CLBP. To this end, different outcome measures are used
in the evaluation of such patients to meet a SMART-oriented (Specific,
Measurable, Achievable, Realistic and Timed) goal. Usually, these outcome
measures can be clinician-administered/assessed or patient self-reported.
In essence, it can be objective or subjective. Some of the outcome measures
include the Oswestry Low Back Pain Disability Questionnaire10,
Pain Disability Index11, Quebec Back Pain Disability Scale12,13,
Curtin Back Screening Questionnaire 14, Roland-Morris Disability
Questionnaire15, Back Performance Scale16 and
Physical Performance Test battery.17 The psychometric properties
of these instruments have been determined in various populations.
Sometimes,the therapist makes
his/her objective assessment without recourse to the patients self-reported assessment. There
is need to compare the patients’ assessment of their functional status during CLBP with the
clinician-observed assessment using standardized outcome measure. This is the focus of the present study.
Research
Questions
The following
questions were raised:
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What is the
self-reported functional status of patients with CLBP?
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What is the
clinician observed functional status of patients with CLBP?
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What is
the relationship between the self-reported functional status and clinician
observed functional status of patients with CLBP?
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What are
the clinical predictors of objective function in patients with CLBP?
Research
design
A cross- sectional
survey design was used. This design was used because the data was obtained
only once from the participants.
Participants
Fifty-one patients
with CLBP of mechanical origin were recruited from the physiotherapy
out patient clinics of the University of Nigeria Teaching Hospital and
the National Orthopedic Hospital both in Enugu, Nigeria
Materials
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Biodata form was
used to record personal information about the participants
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Box numerical scale
was used to assess the present intensity of the pain in the low back
of each participant. It consists of eleven small boxes arranged horizontally
and containing eleven numbers (0-10), with 0 representing “no pain”
while 10 represents the “worst pain” as recommended by Mc Dowell
and Nowell.18
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Back Performance
Scale (BPS) was used to assess objective physical function of the participants.
It consists of five physical performance test of daily activities requiring
mobility of the trunk.16,19 The tests include the sock test,
pick-up test, roll-up test, fingertip- to-floor test, lift test. Each
of the tests of the BPS is scored on a 4-point ordinal scale according
to observed function. The BPS sum score ranges from 0 to 15. Test-retest
reliability of the BPS score is 0.996 while its concurrent validity
has also been demonstrated.19
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Roland-Morris Questionnaire
(Roland and Morris15) was used to assess the subjective disability
of the participants. The original (RMQ-24) which was used in this study
contains 24 yes/no items. Participants were asked whether the statements
applied to them that day (the last 24 hours). The RMQ-24 score was calculated
by adding up the number of “yes” items, ranging from 0 (no disability)
to 24 (maximum disability).
Procedure
The procedure for the study was explained to the participants and their
informed consent was obtained. The following demographic information
were obtained from the participants in terms of age recorded to the
nearest birthday, gender, marital status, educational status, employment
status and date/month of onset of low back pain. The participants’
weights and heights were measured using a dual purpose stadiometer.
The box numerical scale, Roland-Morris Questionnaire (RMQ-24) and the
Back Performance Scale (BPS) were used to assess the present pain intensity,
the subjective and objective functional status of the participants respectively.
Method
of data analysis
The Predictive
Analytics Software (PASW- version 17) was used to analyze the data.
Descriptive statistics of mean, standard deviation and range was used
to summarise the continuous variables. Pearson correlation was used
to determine relationships. Multiple Regressions were used to determine
the predictors of objective function. Alpha level was set at 0.5.
The participants’ demographic characteristics are presented in Table 1 while the results
are collapsed in Tables 2-4.
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Table 1: Demographic
of the participants (N=51) |
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Variable |
Mean ± SD |
Range |
| Age (yrs) |
49.04±14.33 |
23-80 |
| Weight (kg) |
72.98±13.49 |
33-99 |
| Height (m) |
1.68 ±0.07 |
1.50-1.87 |
| BMI (kg/m2) |
26.57±4.29 |
19.63-40.68 |
| Pain intensity
(/10) |
6.33±2.09 |
2-10 |
| RMQ (/24) |
9.76±5.14 |
0-19 |
| BPS (/15) |
6.43±2.9 |
1-14 |
| Duration
(months) |
94.47±85.91 |
3-384 |
The demographic
characteristics of the participants are shown in Table 1. The results
show that the participants mean age and BMI were 49.04±14.33 years
and 26.57±4.29 kg/m2 respectively. The Pain Intensity score had a mean
of 6.33 ± 2.09 on a 10 point scale. The subjective disability
(RMQ) score had a mean of 9.76±+5.14 on a 24 score scale. An objective
disability (BPS) score of 6.43 ±+2.9 on 15 point scale was obtained.
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Table 2:
Frequency distribution of Participants Characteristics (N=51) |
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Variable |
Frequency (n) |
Percentage (%) |
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Sex
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Male |
20 |
39.2 |
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Female
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31 |
60.8 |
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Marital
status |
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Single |
9 |
17.6 |
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Married |
39 |
76.5 |
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Widowed |
3 |
5.9 |
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Highest
Employment status |
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Unemployed |
7 |
13.7 |
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Part time |
3 |
5.9 |
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Full time |
33 |
64.7 |
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Retired |
8 |
15.7 |
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Educational
status |
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None |
3 |
5.9 |
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Primary |
7 |
13.7 |
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Secondary |
9 |
17.6 |
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Tertiary |
32 |
62.7 |
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Nature
of pain |
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Persistent |
24 |
47.1 |
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Recurrent |
27 |
52.9 |
Table 2 shows
the frequency distribution of characteristics of the participants. More
than half (60.80%) of the participants were female while 82.4% of the
participants were either married or widowed. At least more than half
were either employed on full-time (64.7%) or had attained tertiary education
(62.7%). The nature of the pain was more recurrent (52.9%) than persistent
(47.1%) in the participants.
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Table 3: Correction
between the Clinical Variables of Participants |
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BPS |
RMQ |
PI |
Duration |
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BPS |
r |
1 |
-0.122 |
-0.229 |
0.098 |
| Pvalue |
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0.395 |
0.105 |
0.495 |
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RMQ |
r |
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1 |
0.213 |
0.276 |
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Pvalue |
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0.134 |
0.050 |
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PI |
r |
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1 |
-0.013 |
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Pvalue |
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0.929 |
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Duration |
r |
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1 |
| Pvalue |
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BPS:
Back Performance Scale; RMQ: Roland-Morris
Questionnaire; PI: Pain Intensity; r: Pearson Correlation Coefficient
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Correlation
coefficients of the clinical variables are presented in table 3. None
of the variables were significant statistically. Stepwise multiple regressions
showed that all the variables were entered only marital status was a
significant predictor of objective physical function. It accounted for
25.1% of the variance due to back performance scale score.
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Table 4: Model summary of
stepwise regression analysis |
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Model |
R Square change |
F change |
Sig F change |
| 1 |
0.252 |
7.701 |
0.011 |
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Predictors:
(constant), marital status; Dependent
Variable: BPS |
Table 4 shows
that only marital status was a predictor of objective physical function
assessed using BPS
The purpose of this present study was to compare the scores of objective
and subjective physical functions in patients with CLBP. The results
suggests that majority of the patients were middle aged adults (49.04+14.33
years). This raises many possibilities. Since the duration of the pain
since initial onset provided a skewed data, this gives us a clue that
most of the participants have been having LBP since their young adulthood.
In essence, this supports the fact that it is the majority of young
adults that have the onset of this pain. The average BM1 of the participants
suggests that as a group majority of the patients were overweight. Adegoke
and Ezeukwu20 have reported similar findings among patients
with CLBP in their
study which focused on pain intensity, self efficacy and physical
performance of the patients.
The correlation
between the subjective (RMQ) and objective (BPS) physical functions
of the patients was not statistically significant. This suggests that
although these two variables are measuring physical functions, they
are measuring different components of physical function. It may imply
the need for multidimensional approach in assessing function. It is
also necessary to develop an outcome measure with good psychometric
properties to assess function in CLBP taking note of the various domains.
Pain intensity had no significant relationship with the physical function
of the patient. Adegoke and Ezeukwu20 obtained similar results.
This implies that a change in the level of pain intensity does not affect
the functional status of the patient with CLBP. The length of
time the pain has persisted does not relate with either the pain intensity
or the functional status. It goes to suggest that the longer the duration
since initial onset of pain does not necessarily relate to the level
of disability or functional status of the patient. It is also possible
that the other personal or environmental factors may be responsible
for this.
Marital status
was the only significant predictor of the objective functional status.
It has been shown that patient attitudes21, expectancies
of pain or reinjury22,23,
psychological distress levels23,24 and self-efficacy
20,22 can have some impact on patients performance. It is also
possible that the marital life offers a process that improves the function
of the patient with CLBP by integrating a positive balance. Secondly,
majority of the participants were either married (76.5%) or were females
(60.8%). It is therefore possible that the experience of child bearing/birth
offers added advantage that ends in reducing the level of disability.
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Conclusion and Recommendation |
There is no significant association between
subjective and objective function in patients with CLBP. Marital status (married) is a
significant predictor of objective function in CLBP. Therefore, the presence of CLBP
in people does affect both the subjective and the objective functional status of such individuals.
This therefore calls for a multi-disciplinary approach to the management of such individuals.
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