RESEARCH ARTICLE
Factors Influencing Disability due to Low Back Pain Using the Oswestry Disability Questionnaire and the Quebec Back Pain Disability Scale Gyoung-mo Kim1, Chung-hwi Yi2* & Heon-seock Cynn2 1
Department of Physical Therapy, Division of Health Science, Baekseok University, Korea
2
Department of Physical Therapy, College of Health Science, Yonsei University, Korea
Abstract Objectives. The aim of this research was to compare the difference in disability caused by back pain using scores from the Oswestry Disability Questionnaire (ODQ) and the Quebec Back Pain Disability Scale (QUE) according to gender, acute and chronic low back pain (LBP) groups, specific and nonspecific LBP groups and to identify the factors influencing the degree of LBP disability. Methods. One hundred and thirty-three patients with LBP participated in this study. The Visual Analogue Scale (VAS) of ODQ and QUE were used to compare the differences between men and women, acute and chronic and specific and nonspecific LBP groups. We identified the factors influencing the disability of LBP using a stepwise multiple regression. Results. In comparison with the nonspecific LBP group, the VAS, ODQ and QUE scores were significantly higher and the pain duration was significantly longer in the specific LBP group (P < 0.05). A multiple regression equation with VAS and LBP classification explained the 45.4% variance in ODQ and an equation with VAS, LBP classification, pain duration and gender explained 31.1% of the variance in QUE. Conclusions. The degree of disability from back pain assessed using the ODQ score was influenced by a pain severity and LBP type. Also, QUE score was influenced by a pain severity, LBP type, pain duration and gender. To assess the disability caused by back pain accurately using the ODQ and QUE, various factors affecting the scores of the questionnaire must be considered. Copyright © 2014 John Wiley & Sons, Ltd. Received 25 September 2013; Revised 13 February 2014; Accepted 11 March 2014 Keywords disability; low back pain; Oswestry disability questionnaire; Quebec back pain disability scale *Correspondence Chung-hwi Yi, PT, PhD, Department of Physical Therapy, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Kangwondo, 220-710, Korea. Email: [email protected]
Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/pri.1591
Introduction In industrialized countries, low back pain (LBP) is a major public health problem and a leading cause of disability. It also imposes an enormous social and economic burden on the community (Mounce, 2002; Lis et al., 2007). Each year, more than one-quarter of the working population is affected by LBP, with the loss of more than Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
90 workdays (Murphy and Volinn, 1999; Lee et al., 2001). Most acute LBP patients improve over the shortterm, but some patients will proceed to chronic or recurrent LBP with a disability resulting in high costs and reduced quality of life (Hill and Fritz, 2011). The goal of patients with LBP is the restoration of function and a return to the workplace as quickly and
Factors Influencing Back Pain Disability
G.-m. Kim et al.
safely as possible (Nguyen and Randolph, 2007). General recommendations to prevent long-term disability for patients with LBP are early activation and restoration of function (Waddell, 1996). Especially, the evaluation of functional ability with LBP patients is essential for confirming treatment effects and predicting prognosis (Dallmeijer et al., 2005). Standardized self-reported questionnaires are used to evaluate patients with LBP before and after treatment and to detect short-term or long-term clinical changes of symptoms and disabilities (Grotle et al., 2004). Although many questionnaires evaluating disability caused by LBP have been developed, not all questionnaires assess same aspect of disability associated with LBP because there are different items in each questionnaire. The most commonly recommended disability questionnaires for patients with LBP are the Oswestry Disability Questionnaire (ODQ) and Quebec Back Pain Disability Scale (QUE). These are easy to use, reliable and valid assessment tools (Davidson and Keating, 2002). ODQ assesses the level of pain interference with physical activities, whereas QUE describes the perceived difficulty of performing simple physical activities (Bombardier, 2000; Rocchi et al., 2005). Usually, LBP and disability are influenced by physical activities and posture, but the etiological factors associated with LBP are difficult to identify. The risk factors of LBP are divided into individual (age, gender, body mass index and general health), psychosocial (stress, distress, emotional state and pain behaviour), occupational (work load, work environment and job dissatisfaction) and biomechanical categories (Manek and MacGregor, 2005). The prevalence and incidence of LBP and functional level can be affected by age, gender, obesity and socioeconomic level (Andersson et al., 1993; Fillingim et al., 2009). Also, prognosis of LBP and clinical features can be affected by the degree and
duration of pain, the level of disability and experience of back pain (Coste et al., 1994; van den Hoogen et al., 1997; Thomas et al., 1999). The selection of appropriate questionnaire is another critical factor because contents of the questionnaire may influence scores of the LBP and disability (Davidson and Keating, 2002). Although LBP and disability are influenced by many risk factors, it is unclear which factors have the greatest influence on LBP disability (Pincus et al., 2002). The aim of this study was to identify the factors that affect LBP disability. Specifically, we had the following aims: 1) to compare the ODQ and QUE scores according to gender, acute and chronic LBP and specific and nonspecific LBP; and 2) to identify factors influencing the degree of disability from LBP using the ODQ and QUE scores.
Subjects and methods In total, 133 patients with LBP (male = 90, female = 43) who received physical therapy as outpatients at seven hospitals were investigated in this study. The general characteristics of the participants are presented in Table 1. The participants were sufficiently informed of the study procedure and submitted written consent forms. The participants completed a general characteristics questionnaire to provide information regarding their gender, age, height, weight, LBP type (specific or nonspecific LBP), pain duration and Visual Analogue Scale (VAS) score. We classified LBP pain lasting less than 3 months as acute, and pain lasting more than 3 months was chronic (Koes et al., 2010). Also, we used the classification that a specific LBP was that attributable to any diagnosis, including injury, trauma, infection or structural deformity, whereas nonspecific LBP included diagnoses such as lumbago, myofascial
Table 1. Demographic characteristics of the participants (mean ± SD) Parameters
Male (N = 90)
Female (N = 43)
Total (N = 133)
Age (year) Height (cm) Weight (kg) 2 Body mass index (kg m ) Pain duration (mo) VAS score ODQ score QUE score
39.86(12.55) 173.98(0.05) 72.54(8.92) 23.99(2.72) 43.24 ± 49.53 5.24 ± 2.25 29.83 ± 12.49 19.48 ± 17.87
41.74 ± 11.65 160.00 ± 0.05 55.56 ± 9.37 21.71 ± 3.65 55.58 ± 63.80 4.86 ± 2.13 31.81 ± 15.54 24.21 ± 19.61
40.47 ± 12.26 169.47 ± 0.08 67.05 ± 12.05 23.25 ± 3.22 47.23 ± 54.62 5.12 ± 2.21 30.47 ± 13.52 21.01 ± 18.51
SD, standard deviation; VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; QUE, Quebec back pain disability scale.
Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
G.-m. Kim et al.
syndromes, muscle spasm or back sprain (Cherkin et al., 1992). After completing a general questionnaire, each subject completed the ODQ and QUE to determine his or her degree of disability. The ODQ consisted of 10 items describing the impact of pain on different activities of daily living. It has good test–retest reliability (ICC = 0.94), internal consistency (Cronbach’s alpha = 0.93) and criterion-related validity with Roland Morris Disability Questionnaire (r = 0.70) (Fairbank et al., 1980; Rocchi et al., 2005). The QUE was composed of 20 items that describe the perceived difficulty of performing simple physical activities. Its reliability was verified by test–retest (ICC = 0.92) and internal consistency (Cronbach’s alpha = 0.96). It has good validity with Roland Morris Disability Questionnaire (r = 0.80) (Kopec et al., 1995; Rocchi et al., 2005). Each item in both ODQ and QUE is scaled on a six-point Likert scale (range 0–5). The ODQ total scores range from 0 to 50, and the QUE total scores range from 0 to 100. The total score can be interpreted as the percentage of perceived disability; in both ODQ and QUE, a higher score indicates greater disability (Rocchi et al., 2005). We conducted an independent t-test to compare the total ODQ and QUE scores, the VAS score and the pain duration between male and female patients. Also, we conducted an independent t-test to compare the total ODQ and QUE scores and VAS score between acute and chronic LBP groups. In addition, an independent t-test was used to compare the total ODQ and QUE scores and the VAS score and pain duration between specific and nonspecific LBP groups. Finally, multiple regression analysis using a stepwise method was conducted to identify the factors that influence the ODQ and QUE scores. Gender and acute and chronic LBP and LBP type (specific or nonspecific) were used as dummy variables. The level of statistical significance was set at P < 0.05. Statistical analyses were performed using the SPSS 12.0 software (SPSS Inc., Chicago, IL, USA). This study was approved by Yonsei University Wonju Institutional Review Board.
Factors Influencing Back Pain Disability
the VAS (male = 5.24 ± 2.25, female = 4.86 ± 2.13), ODQ (male = 29.83 ± 12.49, female = 31.81 ± 15.54) or QUE scores (male = 19.48 ± 17.87, female = 24.21 ± 19.61) between male and female patients (P > 0.05), (Table 2).
Comparison of VAS, ODQ and QUE scores between the acute and chronic LBP groups No statistically significant differences were observed in the VAS (acute = 5.25 ± 2.17, chronic = 5.09 ± 2.23), ODQ (acute = 31.21 ± 13.82, chronic = 30.28 ± 13.50) or QUE scores (acute = 25.07 ± 21.05, chronic = 19.92 ± 17.73) between the acute and chronic LBP patient groups (P > 0.05), (Table 3).
Comparison of the duration of pain and the VAS, ODQ and QUE scores between the specific and nonspecific LBP groups The duration of pain was significantly increased in the specific LBP group (60.79 ± 65.07) compared with the nonspecific group (35.03 ± 39.73), (P < 0.05). In addition, the VAS (nonspecific = 4.37 ± 1.82, specific = 5.95 ± 2.31), ODQ (nonspecific = 23.49 ± 8.77, specific = 38.24 ± 13.68) and QUE scores (nonspecific = 14.51 ± 14.59, specific = 28.22 ± 19.81) differed significantly
Table 2. Comparison of the pain duration, VAS, ODQ and QUE scores of male and female patients (mean ± SD)
Pain duration(mo) VAS score ODQ score QUE score
Male (N = 90)
Female (N = 43)
P value
43.24 ± 49.53 5.24 ± 2.25 29.83 ± 12.49 19.48 ± 17.87
55.58 ± 63.80 4.86 ± 2.13 31.81 ± 15.54 24.21 ± 19.61
0.224 0.351 0.468 0.169
VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; QUE, Quebec back pain disability scale; SD, standard deviation.
Table 3. Comparison of VAS, ODQ and QUE scores between the acute and chronic LBP groups (mean ± SD) Acute group (N = 28)
Chronic group (N = 105)
P value
5.25 ± 2.17 31.21 ± 13.82 25.07 ± 21.05
5.09 ± 2.23 30.28 ± 13.50 19.92 ± 17.73
0.728 0.938 0.192
Results Comparison of pain duration, VAS, ODQ and QUE scores between male and female patients
VAS score ODQ score QUE score
No statistically significant differences were observed in pain duration (male = 43.24 ± 49.53, female = 55.58 ± 63.80) or
QUE, Quebec back pain disability scale; LBP, low back pain; SD,
Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; standard deviation.
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G.-m. Kim et al.
between the specific and nonspecific LBP groups (P < 0.05), (Table 4). Multiple regression outcomes from the ODQ and QUE scores The VAS score and the LBP type were significantly correlated and explained the 45.4% variance in ODQ (P < 0.05), (Table 5). Also, the VAS score, LBP type, pain duration and gender were significantly correlated and explained the 31.1% variance in QUE (P < 0.05), (Table 6).
Table 4. Comparison of pain duration, VAS, ODQ and QUE scores between the specific and nonspecific LBP groups (mean ± SD) LBP type
Pain duration VAS score ODQ score QUE score
Specific group (N = 63)
Nonspecific group (N = 70)
P value
60.79 ± 65.07 5.95 ± 2.31 38.24 ± 13.68 28.22 ± 19.81
35.03 ± 39.79 4.37 ± 1.82 23.49 ± 8.77 14.51 ± 14.59
0.008 0.000 0.000 0.000
VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; QUE, Quebec back pain disability scale; LBP, low back pain; SD, standard deviation.
Table 5. Multiple regression model for ODQ score Independent variable ODQ score
VAS score LBP type
B
t
P value
Adjusted R
2.649 10.564
6.294 5.685
0.000 0.000
0.324 0.454
2
ODQ, Oswestry disability questionnaire; VAS, visual analogue scale; LBP, low back pain. LBP type (0 = nonspecific LBP group, 1 = specific LBP group).
Table 6. Multiple regression model for QUE score
QUE score
Independent variable
B
t
P value
Adjusted R
VAS score LBP type Pain duration Gender
3.504 10.325 -0.072 7.448
5.358 3.554 -2.807 2.582
0.000 0.001 0.006 0.011
0.210 0.253 0.280 0.311
QUE, Quebec back pain disability scale; VAS, visual analogue scale; LBP, low back pain. LBP type (0 = nonspecific LBP group, 1 = specific LBP group). Gender (0 = male, 1 = female).
2
Discussion The perceived severity of pain, pain duration and ODQ scores were higher in female patients compared with male patients (Kopec et al., 1996; Unruh, 1996). The findings of our study show that the VAS score was higher in male patients compared with female patients, whereas pain duration and ODQ and QUE scores were higher in female patients compared with male patients. However, these differences were not statistically significant. Chronic LBP was defined as pain persisting for more than 3 months (Koes et al., 2010). Chronic LBP patients tend to have an increased risk of functional limitation and pain severity and a decrease in activity of daily living and work activity (Brox et al., 2005). Our results show that the ODQ and QUE scores of the acute LBP group were higher than those of the chronic LBP group, but there was no significant difference in the degree of pain or ODQ and the QUE scores between the acute and chronic LBP groups. Low back pain is usually classified as ‘specific’ or ‘nonspecific’. A specific LBP refers to a diagnosis resulting from a trauma, injury, infection or structural pathology, whereas nonspecific LBP indicates no known structural problem causing the pain (Cherkin et al., 1992). Approximately 35–40% of patients with a specific LBP progress to chronic LBP compared with 10% or less of patients with a nonspecific LBP (Abenhaim et al., 1995). Our results demonstrated that the specific LBP group VAS, ODQ and QUE scores and pain duration were significantly higher than the nonspecific group scores. Therefore, the specific LBP group had a higher risk of disability, a longer duration and a higher sensitivity to pain compared with the nonspecific LBP group. Disability was defined as ‘any restriction or lack of ability resulting from impairment to perform an activity in the manner of within the range considered normal for a human being’ ((WHO), 1980). Disability due to LBP was influenced by many factors, including age, gender, obesity, impairment, pain, general health status and psychological problems (Nisha and MacGregor, 2005). To understand the impact of LBP on the patient’s function and monitor the progress over time, evaluation of disability caused by LBP is an imperative process (Grotle et al., 2004). Questionnaires have been used to provide a reliable and convenient method of collecting a large amount of information on functional limitation (Delitto, 1994). It is viable to recognize the unique features of each questionnaire, Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
G.-m. Kim et al.
so that clinician can choose each questionnaire for the individual who has disability caused by LBP (Davidson and Keating, 200). Our study indicates that the VAS score and the LBP type were significantly predictive of the ODQ score; whereas the VAS score, LBP type, duration of pain and gender were significantly predictive of the QUE score. Because ODQ was developed by describing the impact of pain on different daily living activities (Rocchi et al., 2005), the VAS score is likely a significant predictive variable. QUE is a more useful questionnaire for monitoring progress and is sensitive to change over time. In addition, QUE has more content relating to upper-limb activities compared with ODQ (Davidson and Keating, 2002). For example, ‘reach up to high shelves’, ‘take food out of the refrigerator’ and ‘carry two bags of groceries’. We considered these components to be more familiar to female patients than male patients. We speculate that this explains why pain duration and gender were determined as significant predictive variables in QUE. These results suggest that to assess the disability of back pain accurately using self-reported questionnaires such as ODQ and QUE, the factors that affect the scoring of the questionnaire should be considered and understood. Our study had some limitations. First, because our findings were analysed using data collected by selfquestionnaire responses in a small sample size, pain and disability are both highly variable depending the perception of individual participant. Second, because our study was cross-sectional, we cannot determine the cause and effect relationship of clinical changes in pain and disability over time. Third, we did not consider psychological factors, for example, fear-avoidance behaviour, depression, stress and job satisfaction, that may affect disability in patients with LBP. Further study should incorporate other factors that can affect disability in patients with LBP, and the data should be collected using the performance-based quantitative disability assessment tool.
Conclusion Our study showed that the VAS, ODQ and QUE scores were significantly higher and the pain duration was significantly longer in the specific LBP group compared with the nonspecific LBP group. Additionally, the degree of disability caused by LBP assessed using the ODQ score was influenced by a pain severity and LBP type, and the QUE score was influenced by a pain Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
Factors Influencing Back Pain Disability
severity, LBP type, pain duration and gender. To prevent the progression of disability caused by back pain, effective management, including pain control and accurate evaluation, should be implemented for patients with LBP, particularly specific LBP. To assess the disability associated with back pain using self-reported questionnaires, the factors that affect the scoring of the questionnaires must be identified and examined thoroughly.
REFERENCES Abenhaim L, Rossignol M, Gobeille D, Bonvalot Y, Fines P, Scott S. The prognostic consequences in the making of the initial medical diagnosis of work-related back injuries. Spine 1995; 20: 791–795. Andersson HI, Ejlertsson G, Leden I, Rosenberg C. Chronic pain in a geographically defined general population: studies of differences in age, gender, social class, and pain localization. The Clinical Journal of Pain 1993; 9: 174–182. Bombardier C. Outcome assessments in the evaluation of treatment of spinal disorders: summary and general recommendations. Spine 2000; 25: 3100–3103. Brox JI, Storheim K, Holm I, Reikerås O. Disability, pain, psychological factors and physical performance in healthy controls, patient with sub-acute and chronic low back pain: a case-control study. Journal of Rehabilitation Medicine 2005; 37: 95–99. Cherkin DC, Deyo RA, Volinn E, Loeser JD. Use of the International Classification of Diseases (ICD-9-CM) to identify hospitalizations for mechanical low back problems in administrative databases. Spine 1992; 17: 817–825. Coste J, Delecoeuillerie G, Cohen de Lara A, Le Parc JM, Paolaggi JB. Clinical course and prognostic factors in acute low back pain: an inception cohort study in primary care practice. BMJ 1994; 308: 577–580. Dallmeijer AJ, Dekker J, Roorda LD, Knol DL, van Baalen B, de Groot V, Schepers VP, Lankhorst GJ. Differential item functioning of the functional independence measure in higher performing neurological patients. Journal of Rehabilitation Medicine 2005; 37: 346–352. Davidson M, Keating JL. A comparison of five low back disability questionnaires: reliability and responsiveness. Physical Therapy 2002; 82: 8–24. Delitto A. Are measures of function and disability important in low back care? Physical Therapy 1994; 74: 452–462. Fairbank JC, Couper J, Davies JB, O’Brien JP. The Oswestry low back pain disability questionnaire. Physiotherapy 1980; 66: 271–273. Fillingim RB, King CD, Ribeiro-Dasilva MC, Rahim-Williams B, Riley JL 3rd. Sex, gender and pain: a review of recent clinical and experimental findings. The Journal of Pain 2009; 10: 447–485.
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Grotle M, Brox JI, Vøllestad NK. Functional status and disability questionnaires: what do they assess? A systematic review of back-specific outcome questionnaires. Spine 2004; 30: 130–140. Hill JC, Fritz JM. Psychosocial influences on low-back pain, disability and response to treatment. Physical Therapy 2011; 91: 712–721. Koes BW, van Tulder M, Lin CW, Macedo LG, McAuley J, Maher C. An updated overview of clinical guidelines for the management of non-specific low-back pain in primary care. European Spine Journal 2010; 19: 2075–2094. Kopec JA, Esdaile JM, Abrahamowicz M, Abenhaim L, Wood-Dauphinee S, Lamping DL, Williams JI. The Quebec Back Pain Disability Scale. Measurement properties. Spine 1995; 20: 341–352. Kopec JA, Esdaile JM, Abrahamowicz M, Abenhaim L, Wood-Dauphinee S, Lamping DL, Williams JI. The Quebec Back Pain Disability Scale: conceptualization and development. Journal of Clinical Epidemiology 1996; 49: 151–161. Lee P, Helewa A, Goldsmith CH, Smythe HA, Stitt LW. Low back pain: prevalence and risk factors in an industrial setting. Journal of Rheumatology 2001; 28: 346–351. Lis AM, Black KM, Korn H, Nordin M. Association between sitting and occupational LBP. European Spine Journal 2007; 16: 283–298. Manek NJ, MacGregor AJ. Epidemiology of back disorders: prevalence, risk factors, and prognosis. Current Opinion in Rheumatology 2005; 17: 134–140. Mounce K. Back pain. Rheumatology 2002; 41: 1–5.
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Murphy PL, Volinn E. Is occupational low-back pain on the rise? Spine 1999; 24: 691–697. Nguyen TH, Randolph DC. Nonspecific low-back pain and return to work. American Family Physician 2007; 76: 1497–1502. Nisha JM, MacGregor AJ. Epidemiology of back disorders: prevalence, risk factors and prognosis. Current Opinion in Rheumatology 2005; 17: 134–140. Pincus T, Burton AK, Vogel S, Field AP. A systematic review of psychological factors as predictors of chronicity/ disability in prospective cohorts of low-back pain. Spine 2002; 27: 109–120. Rocchi MB, Sisti D, Benedetti P, Valentini M, Bellagamba S, Federici A. A. Critical comparison of nine different self-administered questionnaires for the evaluation of disability caused by low-back pain. European Medical Physics 2005; 41: 275–281. Thomas E, Silman AJ, Croft PR, Papageorgiou AC, Jayson MI, Macfarlane GJ. Predicting who develops chronic low back pain in primary care: a prospective study. BMJ 1999: 318: 1662–1667. Unruh AM. Gender variations in clinical pain experience. Pain 1996; 65: 123–167. van den Hoogen HJ, Koes BW, Devillé W, van Eijk JT, Bouter LM. The prognosis of low back pain in general practice. Spine 1997; 22: 1515–1521. Waddell G. Low back pain: a twentieth century health care enigma. Spine 1996; 21: 2820–2825. World Health Organization (WHO). International Classification of Impairment, Disability and Handicaps. Geneva: WHO, 1980.
Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
Factors Influencing Disability due to Low Back Pain Using the Oswestry Disability Questionnaire and the Quebec Back Pain Disability Scale Gyoung-mo Kim1, Chung-hwi Yi2* & Heon-seock Cynn2 1
Department of Physical Therapy, Division of Health Science, Baekseok University, Korea
2
Department of Physical Therapy, College of Health Science, Yonsei University, Korea
Abstract Objectives. The aim of this research was to compare the difference in disability caused by back pain using scores from the Oswestry Disability Questionnaire (ODQ) and the Quebec Back Pain Disability Scale (QUE) according to gender, acute and chronic low back pain (LBP) groups, specific and nonspecific LBP groups and to identify the factors influencing the degree of LBP disability. Methods. One hundred and thirty-three patients with LBP participated in this study. The Visual Analogue Scale (VAS) of ODQ and QUE were used to compare the differences between men and women, acute and chronic and specific and nonspecific LBP groups. We identified the factors influencing the disability of LBP using a stepwise multiple regression. Results. In comparison with the nonspecific LBP group, the VAS, ODQ and QUE scores were significantly higher and the pain duration was significantly longer in the specific LBP group (P < 0.05). A multiple regression equation with VAS and LBP classification explained the 45.4% variance in ODQ and an equation with VAS, LBP classification, pain duration and gender explained 31.1% of the variance in QUE. Conclusions. The degree of disability from back pain assessed using the ODQ score was influenced by a pain severity and LBP type. Also, QUE score was influenced by a pain severity, LBP type, pain duration and gender. To assess the disability caused by back pain accurately using the ODQ and QUE, various factors affecting the scores of the questionnaire must be considered. Copyright © 2014 John Wiley & Sons, Ltd. Received 25 September 2013; Revised 13 February 2014; Accepted 11 March 2014 Keywords disability; low back pain; Oswestry disability questionnaire; Quebec back pain disability scale *Correspondence Chung-hwi Yi, PT, PhD, Department of Physical Therapy, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Kangwondo, 220-710, Korea. Email: [email protected]
Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/pri.1591
Introduction In industrialized countries, low back pain (LBP) is a major public health problem and a leading cause of disability. It also imposes an enormous social and economic burden on the community (Mounce, 2002; Lis et al., 2007). Each year, more than one-quarter of the working population is affected by LBP, with the loss of more than Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
90 workdays (Murphy and Volinn, 1999; Lee et al., 2001). Most acute LBP patients improve over the shortterm, but some patients will proceed to chronic or recurrent LBP with a disability resulting in high costs and reduced quality of life (Hill and Fritz, 2011). The goal of patients with LBP is the restoration of function and a return to the workplace as quickly and
Factors Influencing Back Pain Disability
G.-m. Kim et al.
safely as possible (Nguyen and Randolph, 2007). General recommendations to prevent long-term disability for patients with LBP are early activation and restoration of function (Waddell, 1996). Especially, the evaluation of functional ability with LBP patients is essential for confirming treatment effects and predicting prognosis (Dallmeijer et al., 2005). Standardized self-reported questionnaires are used to evaluate patients with LBP before and after treatment and to detect short-term or long-term clinical changes of symptoms and disabilities (Grotle et al., 2004). Although many questionnaires evaluating disability caused by LBP have been developed, not all questionnaires assess same aspect of disability associated with LBP because there are different items in each questionnaire. The most commonly recommended disability questionnaires for patients with LBP are the Oswestry Disability Questionnaire (ODQ) and Quebec Back Pain Disability Scale (QUE). These are easy to use, reliable and valid assessment tools (Davidson and Keating, 2002). ODQ assesses the level of pain interference with physical activities, whereas QUE describes the perceived difficulty of performing simple physical activities (Bombardier, 2000; Rocchi et al., 2005). Usually, LBP and disability are influenced by physical activities and posture, but the etiological factors associated with LBP are difficult to identify. The risk factors of LBP are divided into individual (age, gender, body mass index and general health), psychosocial (stress, distress, emotional state and pain behaviour), occupational (work load, work environment and job dissatisfaction) and biomechanical categories (Manek and MacGregor, 2005). The prevalence and incidence of LBP and functional level can be affected by age, gender, obesity and socioeconomic level (Andersson et al., 1993; Fillingim et al., 2009). Also, prognosis of LBP and clinical features can be affected by the degree and
duration of pain, the level of disability and experience of back pain (Coste et al., 1994; van den Hoogen et al., 1997; Thomas et al., 1999). The selection of appropriate questionnaire is another critical factor because contents of the questionnaire may influence scores of the LBP and disability (Davidson and Keating, 2002). Although LBP and disability are influenced by many risk factors, it is unclear which factors have the greatest influence on LBP disability (Pincus et al., 2002). The aim of this study was to identify the factors that affect LBP disability. Specifically, we had the following aims: 1) to compare the ODQ and QUE scores according to gender, acute and chronic LBP and specific and nonspecific LBP; and 2) to identify factors influencing the degree of disability from LBP using the ODQ and QUE scores.
Subjects and methods In total, 133 patients with LBP (male = 90, female = 43) who received physical therapy as outpatients at seven hospitals were investigated in this study. The general characteristics of the participants are presented in Table 1. The participants were sufficiently informed of the study procedure and submitted written consent forms. The participants completed a general characteristics questionnaire to provide information regarding their gender, age, height, weight, LBP type (specific or nonspecific LBP), pain duration and Visual Analogue Scale (VAS) score. We classified LBP pain lasting less than 3 months as acute, and pain lasting more than 3 months was chronic (Koes et al., 2010). Also, we used the classification that a specific LBP was that attributable to any diagnosis, including injury, trauma, infection or structural deformity, whereas nonspecific LBP included diagnoses such as lumbago, myofascial
Table 1. Demographic characteristics of the participants (mean ± SD) Parameters
Male (N = 90)
Female (N = 43)
Total (N = 133)
Age (year) Height (cm) Weight (kg) 2 Body mass index (kg m ) Pain duration (mo) VAS score ODQ score QUE score
39.86(12.55) 173.98(0.05) 72.54(8.92) 23.99(2.72) 43.24 ± 49.53 5.24 ± 2.25 29.83 ± 12.49 19.48 ± 17.87
41.74 ± 11.65 160.00 ± 0.05 55.56 ± 9.37 21.71 ± 3.65 55.58 ± 63.80 4.86 ± 2.13 31.81 ± 15.54 24.21 ± 19.61
40.47 ± 12.26 169.47 ± 0.08 67.05 ± 12.05 23.25 ± 3.22 47.23 ± 54.62 5.12 ± 2.21 30.47 ± 13.52 21.01 ± 18.51
SD, standard deviation; VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; QUE, Quebec back pain disability scale.
Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
G.-m. Kim et al.
syndromes, muscle spasm or back sprain (Cherkin et al., 1992). After completing a general questionnaire, each subject completed the ODQ and QUE to determine his or her degree of disability. The ODQ consisted of 10 items describing the impact of pain on different activities of daily living. It has good test–retest reliability (ICC = 0.94), internal consistency (Cronbach’s alpha = 0.93) and criterion-related validity with Roland Morris Disability Questionnaire (r = 0.70) (Fairbank et al., 1980; Rocchi et al., 2005). The QUE was composed of 20 items that describe the perceived difficulty of performing simple physical activities. Its reliability was verified by test–retest (ICC = 0.92) and internal consistency (Cronbach’s alpha = 0.96). It has good validity with Roland Morris Disability Questionnaire (r = 0.80) (Kopec et al., 1995; Rocchi et al., 2005). Each item in both ODQ and QUE is scaled on a six-point Likert scale (range 0–5). The ODQ total scores range from 0 to 50, and the QUE total scores range from 0 to 100. The total score can be interpreted as the percentage of perceived disability; in both ODQ and QUE, a higher score indicates greater disability (Rocchi et al., 2005). We conducted an independent t-test to compare the total ODQ and QUE scores, the VAS score and the pain duration between male and female patients. Also, we conducted an independent t-test to compare the total ODQ and QUE scores and VAS score between acute and chronic LBP groups. In addition, an independent t-test was used to compare the total ODQ and QUE scores and the VAS score and pain duration between specific and nonspecific LBP groups. Finally, multiple regression analysis using a stepwise method was conducted to identify the factors that influence the ODQ and QUE scores. Gender and acute and chronic LBP and LBP type (specific or nonspecific) were used as dummy variables. The level of statistical significance was set at P < 0.05. Statistical analyses were performed using the SPSS 12.0 software (SPSS Inc., Chicago, IL, USA). This study was approved by Yonsei University Wonju Institutional Review Board.
Factors Influencing Back Pain Disability
the VAS (male = 5.24 ± 2.25, female = 4.86 ± 2.13), ODQ (male = 29.83 ± 12.49, female = 31.81 ± 15.54) or QUE scores (male = 19.48 ± 17.87, female = 24.21 ± 19.61) between male and female patients (P > 0.05), (Table 2).
Comparison of VAS, ODQ and QUE scores between the acute and chronic LBP groups No statistically significant differences were observed in the VAS (acute = 5.25 ± 2.17, chronic = 5.09 ± 2.23), ODQ (acute = 31.21 ± 13.82, chronic = 30.28 ± 13.50) or QUE scores (acute = 25.07 ± 21.05, chronic = 19.92 ± 17.73) between the acute and chronic LBP patient groups (P > 0.05), (Table 3).
Comparison of the duration of pain and the VAS, ODQ and QUE scores between the specific and nonspecific LBP groups The duration of pain was significantly increased in the specific LBP group (60.79 ± 65.07) compared with the nonspecific group (35.03 ± 39.73), (P < 0.05). In addition, the VAS (nonspecific = 4.37 ± 1.82, specific = 5.95 ± 2.31), ODQ (nonspecific = 23.49 ± 8.77, specific = 38.24 ± 13.68) and QUE scores (nonspecific = 14.51 ± 14.59, specific = 28.22 ± 19.81) differed significantly
Table 2. Comparison of the pain duration, VAS, ODQ and QUE scores of male and female patients (mean ± SD)
Pain duration(mo) VAS score ODQ score QUE score
Male (N = 90)
Female (N = 43)
P value
43.24 ± 49.53 5.24 ± 2.25 29.83 ± 12.49 19.48 ± 17.87
55.58 ± 63.80 4.86 ± 2.13 31.81 ± 15.54 24.21 ± 19.61
0.224 0.351 0.468 0.169
VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; QUE, Quebec back pain disability scale; SD, standard deviation.
Table 3. Comparison of VAS, ODQ and QUE scores between the acute and chronic LBP groups (mean ± SD) Acute group (N = 28)
Chronic group (N = 105)
P value
5.25 ± 2.17 31.21 ± 13.82 25.07 ± 21.05
5.09 ± 2.23 30.28 ± 13.50 19.92 ± 17.73
0.728 0.938 0.192
Results Comparison of pain duration, VAS, ODQ and QUE scores between male and female patients
VAS score ODQ score QUE score
No statistically significant differences were observed in pain duration (male = 43.24 ± 49.53, female = 55.58 ± 63.80) or
QUE, Quebec back pain disability scale; LBP, low back pain; SD,
Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; standard deviation.
Factors Influencing Back Pain Disability
G.-m. Kim et al.
between the specific and nonspecific LBP groups (P < 0.05), (Table 4). Multiple regression outcomes from the ODQ and QUE scores The VAS score and the LBP type were significantly correlated and explained the 45.4% variance in ODQ (P < 0.05), (Table 5). Also, the VAS score, LBP type, pain duration and gender were significantly correlated and explained the 31.1% variance in QUE (P < 0.05), (Table 6).
Table 4. Comparison of pain duration, VAS, ODQ and QUE scores between the specific and nonspecific LBP groups (mean ± SD) LBP type
Pain duration VAS score ODQ score QUE score
Specific group (N = 63)
Nonspecific group (N = 70)
P value
60.79 ± 65.07 5.95 ± 2.31 38.24 ± 13.68 28.22 ± 19.81
35.03 ± 39.79 4.37 ± 1.82 23.49 ± 8.77 14.51 ± 14.59
0.008 0.000 0.000 0.000
VAS, visual analogue scale; ODQ, Oswestry disability questionnaire; QUE, Quebec back pain disability scale; LBP, low back pain; SD, standard deviation.
Table 5. Multiple regression model for ODQ score Independent variable ODQ score
VAS score LBP type
B
t
P value
Adjusted R
2.649 10.564
6.294 5.685
0.000 0.000
0.324 0.454
2
ODQ, Oswestry disability questionnaire; VAS, visual analogue scale; LBP, low back pain. LBP type (0 = nonspecific LBP group, 1 = specific LBP group).
Table 6. Multiple regression model for QUE score
QUE score
Independent variable
B
t
P value
Adjusted R
VAS score LBP type Pain duration Gender
3.504 10.325 -0.072 7.448
5.358 3.554 -2.807 2.582
0.000 0.001 0.006 0.011
0.210 0.253 0.280 0.311
QUE, Quebec back pain disability scale; VAS, visual analogue scale; LBP, low back pain. LBP type (0 = nonspecific LBP group, 1 = specific LBP group). Gender (0 = male, 1 = female).
2
Discussion The perceived severity of pain, pain duration and ODQ scores were higher in female patients compared with male patients (Kopec et al., 1996; Unruh, 1996). The findings of our study show that the VAS score was higher in male patients compared with female patients, whereas pain duration and ODQ and QUE scores were higher in female patients compared with male patients. However, these differences were not statistically significant. Chronic LBP was defined as pain persisting for more than 3 months (Koes et al., 2010). Chronic LBP patients tend to have an increased risk of functional limitation and pain severity and a decrease in activity of daily living and work activity (Brox et al., 2005). Our results show that the ODQ and QUE scores of the acute LBP group were higher than those of the chronic LBP group, but there was no significant difference in the degree of pain or ODQ and the QUE scores between the acute and chronic LBP groups. Low back pain is usually classified as ‘specific’ or ‘nonspecific’. A specific LBP refers to a diagnosis resulting from a trauma, injury, infection or structural pathology, whereas nonspecific LBP indicates no known structural problem causing the pain (Cherkin et al., 1992). Approximately 35–40% of patients with a specific LBP progress to chronic LBP compared with 10% or less of patients with a nonspecific LBP (Abenhaim et al., 1995). Our results demonstrated that the specific LBP group VAS, ODQ and QUE scores and pain duration were significantly higher than the nonspecific group scores. Therefore, the specific LBP group had a higher risk of disability, a longer duration and a higher sensitivity to pain compared with the nonspecific LBP group. Disability was defined as ‘any restriction or lack of ability resulting from impairment to perform an activity in the manner of within the range considered normal for a human being’ ((WHO), 1980). Disability due to LBP was influenced by many factors, including age, gender, obesity, impairment, pain, general health status and psychological problems (Nisha and MacGregor, 2005). To understand the impact of LBP on the patient’s function and monitor the progress over time, evaluation of disability caused by LBP is an imperative process (Grotle et al., 2004). Questionnaires have been used to provide a reliable and convenient method of collecting a large amount of information on functional limitation (Delitto, 1994). It is viable to recognize the unique features of each questionnaire, Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
G.-m. Kim et al.
so that clinician can choose each questionnaire for the individual who has disability caused by LBP (Davidson and Keating, 200). Our study indicates that the VAS score and the LBP type were significantly predictive of the ODQ score; whereas the VAS score, LBP type, duration of pain and gender were significantly predictive of the QUE score. Because ODQ was developed by describing the impact of pain on different daily living activities (Rocchi et al., 2005), the VAS score is likely a significant predictive variable. QUE is a more useful questionnaire for monitoring progress and is sensitive to change over time. In addition, QUE has more content relating to upper-limb activities compared with ODQ (Davidson and Keating, 2002). For example, ‘reach up to high shelves’, ‘take food out of the refrigerator’ and ‘carry two bags of groceries’. We considered these components to be more familiar to female patients than male patients. We speculate that this explains why pain duration and gender were determined as significant predictive variables in QUE. These results suggest that to assess the disability of back pain accurately using self-reported questionnaires such as ODQ and QUE, the factors that affect the scoring of the questionnaire should be considered and understood. Our study had some limitations. First, because our findings were analysed using data collected by selfquestionnaire responses in a small sample size, pain and disability are both highly variable depending the perception of individual participant. Second, because our study was cross-sectional, we cannot determine the cause and effect relationship of clinical changes in pain and disability over time. Third, we did not consider psychological factors, for example, fear-avoidance behaviour, depression, stress and job satisfaction, that may affect disability in patients with LBP. Further study should incorporate other factors that can affect disability in patients with LBP, and the data should be collected using the performance-based quantitative disability assessment tool.
Conclusion Our study showed that the VAS, ODQ and QUE scores were significantly higher and the pain duration was significantly longer in the specific LBP group compared with the nonspecific LBP group. Additionally, the degree of disability caused by LBP assessed using the ODQ score was influenced by a pain severity and LBP type, and the QUE score was influenced by a pain Physiother. Res. Int. (2014) © 2014 John Wiley & Sons, Ltd.
Factors Influencing Back Pain Disability
severity, LBP type, pain duration and gender. To prevent the progression of disability caused by back pain, effective management, including pain control and accurate evaluation, should be implemented for patients with LBP, particularly specific LBP. To assess the disability associated with back pain using self-reported questionnaires, the factors that affect the scoring of the questionnaires must be identified and examined thoroughly.
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