Assessment of disability levels in patients with low back pain based on the type of lumbar spinal disorder

Abstract

BACKGROUND:

Low back pain (LBP) is a common health condition and the leading cause of activity limitation and absenteeism in most parts of the world. One-fifth of patients with LBP develop chronic pain disability.

OBJECTIVE:

This study investigated the disability levels in patients with different types of lumbar spinal disorders.

METHODS:

A total of 528 patients visiting spine clinics between June 2017 and February 2018 were enrolled in this study. A demographic checklist, the patients’ medical records, the Oswestry Disability Questionnaire, and the Visual Analog Scale (VAS) were used to collect the data.

RESULTS:

Non-specific LBP (29.5%) and discopathy (27%) were the most common final diagnoses. The obtained Oswestry Disability Index (ODI) was significantly higher in older patients, those with higher body mass index, more work experience, and smokers. Lower ODI was found in individuals with a history of regular exercise. Most individuals in all diagnostic groups were categorized into the high ODI group ( $p\leqslant$ 0.001).

CONCLUSION:

In patients with lumbar spine lesions, ODI is significantly correlated with age, BMI, work experience, smoking, and the type of disorder (discopathy, spondylolysis, and spondylolisthesis). Regular exercise is associated with lower levels of disability.

Keywords

Disability low back pain oswestry disability index spinal disorder

1. Introduction

Musculoskeletal disorders are among the most common medical problems in all societies. Among musculoskeletal disorders, low back pain (LBP) is well known as a common health condition. LBP is the leading cause of activity limitation and absenteeism in most areas of the world, imposing heavy economic burdens on individuals, families, societies, industries, and governments [1].

The point prevalence of LBP among general populations ranges between 12% and 33%; however, its prevalence may reach 84% throughout life. LBP is the second most common reason for physician visits [2]. LBP can affect all people regardless of their age, gender, and socioeconomic status; however, some relevant factors in the community predispose people to this condition [3].

While only a small proportion of acute back injuries progress towards disability and chronicity, these cases impose major economic and social burdens upon society and cause various personal, physical, economic, and psychosocial problems [4]. Therefore, it would be useful to predict which groups of patients with lumbar spine lesions are at higher risk for disability.

Some studies have shown that one-fifth of patients with LBP develop chronic pain disability, a type of disability which accounts for two-thirds of all direct and indirect costs [5, 6]. Although prognosis is good in the early stages of back pain, it is difficult for those with chronic pain to return to full activity [5, 6].

Some studies have investigated various individual and psychosocial factors contributing to the transition of LBP from acute to chronic pain [7]. Studies have indicated that early screening can help physicians identify people at high risk for chronic LBP [5]. Therefore, further studies are needed to identify patients at risk, and design necessary therapeutic interventions that may improve patient outcomes and prevent disabling chronic pains.

To investigate the disability levels in patients with different types of lumbar spinal disorder, patients visiting two spine clinics were asked to fill out the self-report Oswestry Low Back Pain Disability Questionnaire and a demographics form to measure the effects of LBP on their functional activities.

2. Methods

2.1 Participants

A total of 528 patients (214 females and 314 males) with low back pain lasting for more than 4 weeks (prolonged low back pain) visiting spine clinics at two medical centers affiliated with Iran University of Medical Sciences from June 2017 to February 2018 were enrolled to participate in this cross-sectional descriptive-analytical study. All patients were examined and treated by a spine surgeon. The exclusion criteria were the history of previous surgery ( $n=$ 5) or congenital lumbar spine disorder ( $n=$ 1), symptoms onset less than 4 weeks ( $n=$ 11), unwillingness to participate in the study, and incomplete filling out of the questionnaires ( $n=$ 12).

A checklist including the variables of age, gender, marital status, education, smoking habits, routine exercise (regular physical activity at least 3 times a week for over 30 minutes), and work experience was handed out among the participants to collect demographic information. To determine the participants’ BMI, the height and weight of them were measured by a trained technician using a single scale and measuring tape in the clinic. A pack/year was employed to assess the smoking status by multiplying the number of packs of cigarettes smoked per day by the number of years one has been a smoker. Information associated with the medical history, including previous surgery, congenital lumbar spine disorders, lumbar spine trauma, and final diagnoses, were extracted from the medical records of participants.

The following criteria were used to diagnose various lumbar spinal disorders:

•
Non-specific low back pain (NSLP): Patients complaining of low back pain for more than 4 weeks without pathological findings on imaging.
•
Discopathy: Patients with low back pain for more than 4 weeks and disc degeneration or herniation on imaging except for protrusion or extrusion cases who have undergone surgery.
•
Traumatic fracture: Patients complaining of low back pain more than one month and a history of traumatic vertebral fracture who have not undergone surgery.
•
Misalignment (scoliosis and lordosis); in the absence of spinal stenosis, patients with scoliosis greater than 10 degrees in the lumbar region or with a lumbar lordosis reduction with pelvic incidence mismatch.
•
Spinal stenosis: Patients with low back pain for more than 4 weeks and evidence of spinal stenosis on imaging. Patients with DJD who had spinal stenosis were assigned to the spinal stenosis group.

2.2 Measurement tools

2.2.1 Oswestry Low Back Disability Questionnaire

The Oswestry Low Back Disability Questionnaire was used to measure the severity of disability caused by lumbar spine problems. The questionnaire consists of 10 items including pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sexual life, social life, and traveling. Each section is answered based on a six-point scale. The scores zero and five indicate the best and worst possible conditions, respectively. If all the questions are answered, the final percentage of disability for each individual will be calculated by dividing the obtained score by 50 (the maximum attainable score). Based on the obtained Oswestry Disability Index (ODI), each participant will be assigned to one of the following groups: 0–20%: minimal disability; 21–40%: moderate disability; 41–60%: severe disability; 61–80%: crippled; 81–100%: bed-bound. The validity and reliability of the Persian version of this questionnaire have been confirmed (Cronbach’s Alpha $=$ 0.75; correlation coefficient $=$ 0.91) [8]. Based on their disability indices, the participants were categorized under two groups, those with minimal and moderate disability in group I (ODI $\leqslant$ 40%) and others in group II (ODI $>$ 40%).

2.2.2 Visual Analogue Scale

The Visual Analogue Scale (VAS) was completed by the participants to measure their pain levels. The scale ranges from zero to ten, representing the least and most possible pain, respectively.

All participants signed an informed written consent form, and the study was approved by the Ethics Committee of Iran University of Medical Sciences (Code: IR.IUMS.FMD.REC 1396.9411308003).

2.3 Statistical analysis

The demographic and clinical characteristics of participants were analyzed using descriptive statistics. Chi-squared tests were used to investigate associations between disability index and categorical variables. Regression analysis was used to eliminate the effects of confounding variables.

3. Results

Table 1 presents the demographic information of the participants. The study sample consisted of 528 patients, 60% of whom were male. The mean age of the study sample was about 40 years and the mean BMI was about 26. Moreover, 39% of the participants were smokers and 25% of them exercised regularly (at least three times a week for over 30 minutes). The mean score of pain intensity was 7.15 $\pm$ 1.60, with a range of 3 to 10. The mean score of disability was 24.11 $\pm$ 7.94, with a range of 1 to 45, and that of ODI was 49.53 $\pm$ 16.10, with a range of 2 to 90. Most of the participants suffered from severe (48.5%) and moderate (28%) levels of disability. The prevalence of different types of spinal disorders, the description based on the study variables, and their prevalence in each of the disability groups are shown in Table 2.

Table 1
Description of qualitative and quantitative variables

Variable	M $\pm$ SD	N (%)
Age (y)	40.54 $\pm$ 12.10
Body mass index (kg/m ${}^{2}$ )	26.49 $\pm$ 3.05
Pain severity	7.15 $\pm$ 1.60
Pack year	4.76 $\pm$ 8.02
Smoking status
Yes		206	(39)
No		322	(61)
Gender
Female		214	(40.5)
Male		314	(59.5)
Marital status
Single		132	(25)
Married (or divorced)		396	(75)
Education
High school		156	(29.5)
Associate degree and diploma		316	(59.8)
Bachelor and Master’s degree		56	(10.6)
Exercise
Yes		136	(25.8)
No		392	(74.2)
Disability index
Minimal		14	(2.7)
Moderate		148	(28)
Severe		256	(48.5)
Crippled		90	(17)
Bed-bound		20	(3.8)

The mean age, BMI, and work experience of participants in Group II (ODI $>$ 40%) was significantly higher than those in Group I (ODI $\leqslant$ 40%) ( $P\leqslant$ 0.001). Although the severity of disability in smokers was not significantly different from non-smokers, the number of participants who smoked $\geqslant$ 2 pack/year was higher in Group II ( $p=$ 0.021). The percentage of single people in Group I (ODI $\leqslant$ 40%) was significantly higher than married people ( $p=$ 0.006). The number of people who exercised regularly was lower in Group II (54% vs. 67%) ( $p<$ 0.001) (Table 3). Most participants in all diagnostic groups were categorized under the ODI $>$ 40% group, indicating the higher disability levels ( $p<$ 0.001) (Table 4).

After performing regression analysis to eliminate the effects of confounding variables, the obtained ODI still had a significant relationship with the mean score of the main research variables, namely the diagnosis (discopathy, spondylolysis, and spondylolisthesis), pain intensity, and history of regular exercise (Table 5).

4. Discussion

A few studies have so far investigated the severity of disability in patients with lumbar spine disorders in Iran. In this study, 4% of the patients suffered from severe disability (Group 5 or the bed-bound group). This figure is estimated to be around 1% among the working population of the US [9]. This difference may

Table 2
The prevalence of different types of spine disorders, the description based on study variables and prevalence in different disability groups

[height=0.8cm,width=3.8cm]DiagnosisVariables			Age	BMI	Pain	Gender N (%)				Disability index N (%) ${}^{\ast}$ [%] ${}^{{\dagger}}$
	N (%)		Mean $\pm$ SD			Male		Female		Minimal	Moderate	Severe	Crippled	Bedbound
Discopathy	146	(27.7)	43.78 $\pm$ 9.25	27.37 $\pm$ 2.86	7.70 $\pm$ 1.50	100	(68.5)	46	(31.5)	0 (0) [0]	16 (11) [10.8]	80 (54.8) [31.2]	42 (28.8) [46.7]	8 (5.5) [40]
Spinal Stenosis	14	(2.7)	48.00 $\pm$ 12.35	26.82 $\pm$ 2.40	8.14 $\pm$ 1.51	6	(42,9)	8	(57.1)	0 (0) [0]	2 (14.3) [1.4]	6 (42.9) [2.3]	6 (42.9) [6.7]	0 (0) [0]
Misalignment	74	(14)	34.03 $\pm$ 13.07	25.66 $\pm$ 3.49	6.35 $\pm$ 1.34	36	(48.6)	38	(51.4)	4 (5.4) [28.6]	38 (51.4) [25.7]	30 (40.5) [11.7]	2 (2.7) [2.2]	0 (0) [0]
Non-specific low back pain	156	(29.5)	35.04 $\pm$ 10.70	25.69 $\pm$ 2.94	6.68 $\pm$ 1.65	88	(56.4)	68	(43.6)	6 (3.8) [42.9]	58 (37.2) [39.2]	76 (48.7) [29.7]	16 (10.3) [17.8]	0 (0) [0]
Traumatic fracture	12	(2.3)	32.50 $\pm$ 10.30	25.77 $\pm$ 2.62	9.17 $\pm$ 0.71	8	(66.7)	4	(33.3)	0 (0) [0]	2 (16.7) [1.4]	2 (16.7) [0.8]	2 (16.7) [2.2]	6 (50) [30]
Degenerative joint disease	76	(14.4)	51.18 $\pm$ 9.51	26.87 $\pm$ 2.74	7.16 $\pm$ 1.45	44	(57.9)	32	(42.1)	4 (5.3) [28.6]	22 (28.9) [14.9]	40 (52.6) [15.6]	6 (7.9) [6.7]	4 (5.3) [20]
Spondylolysis and spondylolisthesis	32	(6.1)	44.13 $\pm$ 9.32	27.74 $\pm$ 3.31	7.63 $\pm$ 1.33	20	(62.5)	12	(37.5)	0 (0) [0]	2 (6.2) [1.4]	14 (43.8) [5.5]	14 (43.8) [15.6]	2 (6.2) [10]
Others (cancer and osteomyelitis)	18	(3.4)	36.89 $\pm$ 9.97	26.17 $\pm$ 2.64	7.11 $\pm$ 1.13	12	(66.7)	6	(33.3)	0 (0) [0]	8 (44.4) [5.4]	8 (44.4) [3.1]	2 (11.1) [2.2]	0 (0) [0]

${}^{*}$ Percentage of each diagnosis in disability groups. ${}^{\dagger}$ Percentage of various diagnoses in each disability group.

Table 3

Relationship between disability index and study variables

	Mean $\pm$ SD/N (%)		$P$ value	OR (95%CI)
	Group I (ODI $\leqslant$ 40%)	Group II (ODI $>$ 40%)
Age (y)	35.80 $\pm$ 12.58	42.62 $\pm$ 11.28	$<$ 0.001
BMI (kg/m ${}^{2}$ )	25.53 $\pm$ 3.16	26.91 $\pm$ 2.91	$<$ 0.001
Work experience (y)	11.15 $\pm$ 9.48	16.75 $\pm$ 9.99	$<$ 0.001
Pain	6.30 $\pm$ 1.42	7.53 $\pm$ 1.53	$<$ 0.001
Gender
Female	73 (34)	141 (66)	0.149	0.752 (0.517–1.094)
Male	88 (28)	226 (82)
Marital status
Single	53 (40.2)	79 (59.8)	0.006	1.78 (1.18–2.70)
Married (or divorced)	108 (27.3)	288 (72.7)
Smoking status
Pack/year $<$ 2	36 (40)	60 (60)	0.021	2.12 (1.15–3.92)
Pack/year $\geqslant$ 2	24 (22)	85 (78)
Exercise
Yes	62 (45)	74 (54)	$<$ 0.001	2.48 (1.65–3.72)
No	99 (33)	293 (67)
${}^{*}$ Oswestry Disability Index.

Table 4

Relationship between disability index and diagnostic groups

[height=0.8cm,width=2.4cm]ODI groupsDiagnosis	Discopathy	Spinal stenosis	Misalignment	NSLBP ${}^{\ast}$	Traumatic fracture	DJD ${}^{{\dagger}}$	Spondylolysis and spondylolisthesis	Others	$P$ value
ODI $\leqslant$ 40	11 (16)	14.3 (2)	56.8 (42)	40.4 (63)	16.7 (2)	34.2 (26)	6.2 (2)	44.4 (8)	$<$ 0.001
ODI $>$ 40	89 (130)	85.7 (12)	43.2 (32)	59.6 (93)	83.3 (10)	65.8 (50)	93.8 (30)	55.6 (10)
${}^{*}$ Non-specific low back pain. ${}^{\dagger}$ Degenerative joint disease.

Table 5

Regression analysis of the relationship between disability index and diagnostic groups

Variable	ß	$P$ value	Odds ratio	95% CI
Age (y)	0.013	0.610	1.013	0.964–1.065
BMI (kg/m ${}^{2}$ )	0.036	0.389	1.03	0.955–1.126
Work experience (y)	0.031	0.306	1.03	0.972–1.095
Smoke	$-$ 0.066	0.777	0.936	0.593–1.478
Exercise	0.580	0.019	1.78	1.102–2.896
Pain	0.428	$<$ 0.001	1.53	1.316–1.787
Discopathy	1.403	0.013	4.06	1.339–12.356
Spinal stenosis	0.775	0.413	2.17	0.339–13.928
Misalignment	$-$ 0.235	0.675	0.791	0.263–2.373
NSLBP	0.440	0.405	1.55	0.552–4.36
Traumatic fracture	0.697	0.463	2.007	0.312–12.891
DJD	$-$ 0.307	0.594	0.736	0.238–2.272
Spondylolysis and spondylolisthesis	1.883	0.036	6.574	1.136–38.056
Others (cancer and osteomyelitis)	0.463	0.363	1.58	0.586–4.304

be due to the lack of workplace safety training programs and the failure to execute proper rehabilitation programs in developing countries like Iran.

The results demonstrated that pain intensity, final diagnosis (discopathy, spondylolysis, and spondylolisthesis), and regular exercise are the most important factors associated with disability in patients with lumbar spine disorder. Accordingly, in patients with lumbar spine disorder, those with greater pain intensity and a final diagnosis of discopathy, spondylolysis, or spondylolisthesis are expected to have higher degrees of disability; however, those with a history of regular exercise were suffering from lower levels of disability. The following studies confirm the results of the present research:

A case-control study was conducted on two groups of military soldiers to identify risk factors associated with LBP and develop an occupational disability prevention program. Based on the results, age (OR $=$ 1.13) and lack of aerobic exercise (OR $=$ 2.2) were major predictive factors for LBP disability [10]. In a prospective cohort study by Turner et al., 1068 workers were studied for occupational disability, 6 months after submitting their disability claims. At 6 months, 196 workers (18.4%) received disability compensation. Age and pain intensity were the most important predictors of occupational disability. This is in line with the present results in terms of pain intensity. In the present study, the initial analyses showed a significant relationship between age and ODI; however, this relationship was not significant after adjusting for other research variables through regression analysis [11].

Crook et al. conducted a systematic review study to investigate the predictive factors for occupational disability in patients with LBP. Based on the results, pain intensity was identified as a prognostic factor for disability, which is consistent with the present results [4].

Wetstein et al. investigated pain intensity, disability levels, and quality of life of 228 patients with non-specific chronic back pain, with a mean age of 59.1 $\pm$ 10.2 (age range 41–82 years), as well as the effect of age on these variables. They found that older patients had higher levels of disability. This is consistent with the initial analyses of the present study. It is noteworthy that in their study, the mean age of the participants was 18 years higher than that of the present study (41.66 $\pm$ 11.19) [12].

In a meta-analysis of randomized controlled trials, Oesch et al. investigated the effectiveness of exercise on occupational disability in patients with non-specific chronic LBP. The results showed a significant relationship between lack of exercise and long-term occupational disability (OR $=$ 0.66; CI $=$ 95%; 0.48–0.92) [13].

Webb et al. conducted a multi-phase cross-sectional survey to estimate the prevalence of various types of spinal pain and predictors of LBP disability. The results indicated that obesity (OR $=$ 1.7; CI $=$ 95%; 1.1–2.7) is a predictive factor for LBP disability. In the present study, the Chi-square test showed that an increase in BMI is associated with increased disability levels. However, in the present study, the relationship did not persist after adjusting the results, which may be due to the large sample size ( $n=$ 5752) in the above study [14].

Lanier et al. conducted a prospective study on 116 patients with acute mechanical LBP. They measured short-term outcomes by the number of lost workdays and long-term outcomes by disability levels at a six-week follow-up. They concluded that cigarette smoking is associated with long-term disability; however, obesity was not associated with long-term disability. In the present study, there were significant relationships between smoking (Pack/year $\geqslant$ 2) and high BMI with ODI in the initial analyses; however, regression analyses did not confirm these relationships. The lack of association between ODI and smoking is probably because of fear of correct self-report of smoking [15].

In 2017, Shirazi et al. conducted a study on 217 students (with a mean age of 21.33 $\pm$ 1.81) at Lahore Medical and Dental College to investigate the relationship between disability levels and non-specific LBP. Based on their findings, 64% of the students had mild disability, 34% had moderate disability, and 2% suffered from severe disability. In the present study, a higher percentage of the participants had a severe disability, which is probably due to the higher mean age of the patients in our study. Shirazi et al. found no significant relationship between non-specific LBP and disability ( $p>$ 0.05). In the present study, there was no significant relationship between non-specific LBP and disability [16].

This study investigated the relationship between disability and various types of lumbar spine disorders. In Iran, few studies (with smaller sample sizes) have so far investigated the severity of disability in patients with lumbar spine disorder. The cross-sectional design of the study and poor cooperation of patients in completing the questionnaires were among the limitations of this study.

5. Conclusion

In patients with lumbar spine disorder, disability index is significantly correlated with age, BMI, work experience, smoking habits, and the type of lesions; as the obtained ODIs were significantly higher in older patients, those with a higher BMI, longer work experience, smokers, and those who experienced higher levels of pain. Moreover, lower ODIs were found in participants with a history of regular exercise. Therefore, regular exercise seems to be associated with lower degrees of disability in patients with lumbar spine disorder; however, prospective studies are needed to investigate the predictive effects of regular exercise on the severity of disability.

Footnotes

Acknowledgments

This study was supported by deputy of research of Iran University of Medical Sciences.

Conflict of interest

None to report.

References

Hoy

March

Woolf

Blyth

Brooks

Smith

, et al. The global burden of neck pain: estimates from the global burden of disease 2010 study. Annals of the Rheumatic Diseases. 2014; 73(7): 1309–15.

Omidi-Kashani

Hasankhani

Moghadam

Esfandiari

. Prevalence and severity of preoperative disabilities in iranian patients with lumbar disc herniation. Archives of Bone and Joint Surgery. 2013; 1(2): 78.

Kouka

. Public Health Burden of Low Back Pain among the US Working Population: Summary of Systematic Reviews (2000–2014) 2016.

Crook

Milner

Schultz

Stringer

. Determinants of occupational disability following a low back injury: a critical review of the literature. Journal of Occupational Rehabilitation. 2002; 12(4): 277–95.

Wertli

Held

Campello

Weiner

. Obesity is associated with more disability at presentation and after treatment in low back pain but not in neck pain: findings from the OIOC registry. BMC Musculoskeletal Disorders. 2016; 17(1): 140.

Balagué

Mannion

Pellisé

Cedraschi

. Non-specific low back pain. The Lancet. 2012; 379(9814): 482–91.

Govindu

Babski-Reeves

. Effects of personal, psychosocial and occupational factors on low back pain severity in workers. International Journal of Industrial Ergonomics. 2014; 44(2): 335–41.

Mousavi

Parnianpour

Mehdian

Montazeri

Mobini

. The oswestry disability index, the roland-morris disability questionnaire, and the quebec back pain disability scale: translation and validation studies of the iranian versions. Spine. 2006; 31(14): E454–E9.

Rosenstock

Cullen

Brodkin

Redlich

. Textbook of clinical occupational and environmental medicine. 2004.

10.

Feuerstein

Berkowitz

Huang

. Predictors of occupational low back disability: implications for secondary prevention. Journal of Occupational and Environmental Medicine. 1999; 41(12): 1024–31.

11.

Turner

Franklin

Fulton-Kehoe

Sheppard

Wickizer

, et al. Worker recovery expectations and fear-avoidance predict work disability in a population-based workers’ compensation back pain sample. Spine. 2006; 31(6): 682–9.

12.

Wettstein

Eich

Bieber

Tesarz

. Pain intensity, disability, and quality of life in patients with chronic low back pain: does age matter? Pain Medicine. 2018; 20(3): 464–75.

13.

Oesch

Kool

Hagen

Bachmann

. Effectiveness of exercise on work disability in patients with non-acute non-specific low back pain: systematic review and meta-analysis of randomized controlled trials. Journal of Rehabilitation Medicine. 2010; 42(3): 193–205.

14.

Webb

Brammah

Lunt

Urwin

Allison

Symmons

. Prevalence and predictors of intense, chronic, and disabling neck and back pain in the UK general population. Spine. 2003; 28(11): 1195–202.

15.

Lanier

Stockton

. Clinical predictors of outcome of acute episodes of low back pain. The Journal of Family Practice. 1988; 27(5): 483–9.

16.

Arshad

. Association of Non Specific Lower Back Pain With Level of Disability among Medical Students of (ANMCL) Lahore. Age. 21(1.813): 18.