Abstract
Objective
To determine the correlation between the Quebec Task Force Classification (QTFC) system and outcome in patients with non-specific low back pain (LBP).
Methods
Forty-nine patients who were treated in outpatient physical therapy clinics of Catholic Health System (CHS) of Western New York (WNY) were classified according to the QTFC at the initial examination by physical therapists (PTs) with training in Mechanical Diagnosis and Therapy (MDT). The patient’s perceived level of function was assessed with the Focus On Therapeutic Outcomes (FOTO) tool at the initial examination, 2 weeks following the initiation of physical therapy and again at discharge.
Results
A linear regression model between acuity and change in FOTO score was performed and demonstrated statistical significance (P<0·05) as the more favorable outcome was found with the more acute patients. Spearman correlations between change in FOTO score and QTFC, duration of treatment and acuity of condition, and number of visits and change in FOTO score were not found to be statistically significant.
Conclusions
The patients treated in this study demonstrated functional improvement in an average of eight visits, indicating efficacious care. Future research is needed to determine prioritized intervention strategies for designated LBP classifications.
Keywords: Low back pain classification, Outcomes, McKenzie
Background
Non-specific low back pain (LBP) is a common musculoskeletal disorder with an overall incidence between 1·5 and 36% of the general population, which results in a tremendous economic burden to society.1 A systematic review examining reports of LBP established the mean 1 month prevalence of LBP to be 23%.2 Deyo et al.3 examined the prevalence of LBP in the United States and found that out of the 36,787 adult respondents, 26% reported LBP lasting longer than a whole day within the previous 3 months. Research also demonstrated that the prevalence of LBP peaks in individuals between the ages of 41 and 50 years and decreases thereafter.4 Current research suggests the 1-year incidence of first ever episodes of LBP ranges between 6 and 15% and the one-year incidence of any episodes of LBP ranges between 2 and 36%.5 Incidence rates are highly variable due to the recurrent nature of LBP and the inability of many individuals to recall age at which their symptoms first appeared.6 Impacting the high incidence and prevalence rates of non-specific LBP through the determination of the most efficient treatment strategies implemented by physical therapists (PTs) is a goal that may reduce health care costs.
Standardized outcome assessments provide a quantitative analysis of a patient’s functional status, which allows PTs and third-party payers to assess the value and efficiency of physical therapy treatment interventions. The Focus on Therapeutic Outcomes (FOTO) is an electronically administered survey that assesses the patient’s perceived level of function. The FOTO tool is designed to determine rehabilitation effectiveness and efficiency in outpatient orthopedic clinical practice.6 The FOTO tool includes the patient’s perceived health status, age, symptom acuity, surgical history, and comorbid conditions, which factor into the person's overall functional status.6,7 The inclusion of comorbidities enable PTs to evaluate the relationship between their treatment strategy and other factors that may impact function.7
Evidence shows that treatment-based PT classification systems offer more favorable outcomes for patients diagnosed with LBP.8–11 The Quebec Task Force Classification (QTFC) system has been shown to be reliable in classifying patients into 1 of 11 categories based upon the presence and location of pain, neurological signs, radiographic imaging, and surgical history, which is shown in Table 1. Furthermore, patients are subdivided according to their pain duration and working status.12–14 Loisel et al.14 found that subjects classified as having distal radiating pain (categories 3 and 4) at baseline were more likely to have a lower functional status, higher pain level, and no return to regular work at the 1-year follow-up evaluation. They were also more likely to accumulate more days of full compensation and to cost more after a mean follow-up period of 6·5 years, thereby indicating predictive validity of the QTFC.15 In addition to classification based on the aforementioned criteria, patients are subgrouped according to acuity of symptoms in the QTFC (a – <7 days, b – 7 days–7 weeks, c – >7 weeks).16 Badke and Boissonnault17 found that functional improvement scores from initial visit to discharge were significantly less for patients with chronic LBP than for those with acute LBP symptoms. Kongsted et al.18 found subgrouping patients with LBP based on pain location and neurological signs were associated with activity limitation, but not global perceived effect.18 Although evidence exists to support the predictive validity of the QTFC in predicting functional status in patients with LBP, more research is required to determine if a relationship exists between QTFC scores and functional outcomes.13–15
Table 1.
The Quebec Task Force Classification (QTFC) system
| Category | Description |
|---|---|
| 1 | Back pain without radiation |
| 2 | Back pain with radiation to proximal extremity |
| 3 | Back pain with radiation to distal extremity |
| 4 | Back pain with radiation to distal extremity and positive neurological signs (focal weakness, asymmetry of reflexes, sensory loss in a dermatome, or loss of bowel, bladder, or sexual function) |
| 5 | Presumptive compression of a spinal nerve root on radiographs (i.e. instability or fracture) |
| 6 | Compression of a spinal nerve root confirmed by special imaging techniques (i.e. as category 4 with moderate or severe findings on neurological review at appropriate level |
| 7 | Spinal stenosis |
| 8 | Post-surgical status, 1–6 months after intervention, asymptomatic (8·1) or symptomatic (9·2) |
| 9 | Post-surgical status, >6 months after intervention, asymptomatic (8·1) or symptomatic (9·2) |
| 10 | Post-surgical status, >6 months after intervention, asymptomatic (8·1) or symptomatic (9·2) |
| 11 | Other diagnoses (i.e. metastases, visceral disease, and fracture) |
| Subclassification a | 0–7 days from onset |
| Subclassification b | 7 days–7 weeks from onset |
| Subclassification c | >7 days from onset |
The purpose of this study was to determine the correlation between patient intake scores on the QTFC system to their change in functional status scores as determined by data collected at intake and discharge with the FOTO tool. The treating PTs were trained in Mechanical Diagnosis and Therapy (MDT).
Methods
This research was approved by the Daemen College Human Subjects Review Committee and the Catholic Health System Institutional Review Board. A retrospective analysis of the classification of 49 patients with non-specific LBP who had completed the FOTO instrument at intake and at discharge and who were classified according to the QTFC was performed. The 49 patients completed the FOTO at intake and discharge, thereby providing a complete data set. Inclusion criteria for the study were subjects ≧18 years old and diagnosis of LBP within the Catholic Health System (CHS) of Western New York (WNY). Subjects who presented with a history of spinal surgery, a progressive disease process, psychological illness, pregnancy, experienced symptoms relative to severe neurological disorders, were non-English speaking, or engaged in litigation related to their LBP were excluded. Additionally, individuals insured through Workers’ Compensation or No Fault insurance companies were excluded from the study. Examining PTs documented each participant’s initial QTFC based on the location of symptoms and acuity and performed a standardized PT examination that included repeated end-range spinal movements as described by McKenzie.1 The FOTO tool, an electronic questionnaire based on patient response, was administered at intake and discharge and was used to discriminate a change in functional status. The FOTO calculates a predicted functional score based on the patient’s ratings of function, their fear-avoidance, and other comorbidities. Potential subjects were informed of the procedures and given the informed consent form to read and sign prior to participation. After informed consent was obtained, the FOTO tool was re-administered 2 weeks following the initiation of physical therapy and again at discharge. The number of visits, duration of treatment, and type of physical therapy intervention were also documented. After data collection, a correlational analysis was performed by student researchers at Daemen College using the information gathered from CHS clinics.
Physical Therapists
Seven PTs participated in the study. Six of the seven PTs had successfully completed Part A (Lumbar) of the McKenzie course series. Four of the seven PTs were certified in the approach (Cert. MDT) and one held a diploma (Dip MDT). The McKenzie (MDT) approach has been found to have clinical utility in a subgroup of patients and includes the utilization of repeated end-range spinal movements to determine a classification.8 A PT who had no prior training in MDT contributed one patient to the total subject pool (n = 49).
Statistical Analysis
The initial hypothesis of the study was that there would be a relationship between QTFC and the patient outcome as measured by FOTO. The Statistical Product and Service Solutions (SPSS, version 8, Chicago, IL) computer program was used in order to analyze the data. Quebec Task Force Classification categories were coded in SPSS as ordinal data; therefore, a non-parametric correlation coefficient (Spearman's rho) to determine the strength and direction of the relationship was utilized. For the purposes of this study, the QTFC a and b subclassifications were collapsed into one category of b. This was done because few patients are referred to the participating clinics in the acute stage. Secondary analyses included the relationships between duration of treatment (days) and acuity of symptoms (b or c); change in FOTO score and acuity of symptoms; and number of visits and changes in FOTO scores. Spearman's rho coefficient was used to analyze the relationship between duration and acuity and between change in FOTO score and acuity; however, a parametric correlation coefficient (Pearson) was used to evaluate the relationship between number of visits and change in FOTO score. A linear regression model was included in our data analysis to quantify the relationship between change in FOTO score (dependent) and acuity of symptoms (independent). The significance value was set at P value <0·05 for all tests.
Results
A total of 49 participants were assessed who met the inclusion criteria for the study. The frequency of each QTFC category was determined to be as follows: QTFC 1 (18%), QTFC 2 (33%), QTFC 3 (41%), QTFC 4 (2%), and QTFC 5 (6%). The distribution of acuity was nearly equal with 49% of the participants presenting with symptoms between 7 days and 7 weeks (b) and 51% presenting with symptoms >7 weeks (c). Table 2 outlines the means of the data set including the following categories: intake FOTO, re-evaluation FOTO, change in FOTO, predicted FOTO, number of visits, and duration of treatment. The results indicated that subgroup b had a lower mean FOTO intake score of 48·76 and demonstrated a significant change in their FOTO score. The mean change in FOTO score for subgroup b was 17·2, whereas the minimal clinically important difference (MDC) was 5–8 ranging from clinical significance to statistical significance.19 Table 2 shows that the average number of visits was 8·33. According to practice pattern 4D in the Guide to Physical Therapist Practice, the conventional plan of care for this patient population ranges from 3 to 36 days.20 These results indicated that in this sample, patients with non-specific LBP showed greater functional improvements with decreased pain within fewer visits.
Table 2.
Comparison of mean intake FOTO, re-evaluation FOTO, change in FOTO score, predicted FOTO, visits, and treatment duration
| All data (n = 49) | |
| Mean intake FOTO | 48·71 |
| Mean re-evaluation FOTO | 67·98 |
| Mean change FOTO | 17·29 |
| Mean predicted FOTO | 51·29 |
| Mean visits | 8·33 |
| Mean duration (in days) | 44·43 |
| Subgroup b (n = 24) | |
| Mean intake FOTO | 48·76 |
| Mean re-evaluation FOTO | 72·54 |
| Mean change FOTO | 22·78 |
| Mean predicted FOTO | 51·5 |
| Mean visits | 7·8 |
| Mean duration (in days) | 42·17 |
| Subgroup c (n = 25) | |
| Mean intake FOTO | 51·61 |
| Mean re-evaluation FOTO | 63·6 |
| Mean change FOTO | 11·99 |
| Mean predicted FOTO | 51·08 |
| Mean visits | 8·67 |
| Mean duration (in days) | 49·2 |
FOTO: focus on therapeutic outcomes.
Table 3 depicts the correlations between the QTFC and FOTO. The following non-parametric correlation tests were not found to be statistically significant (P>0·05): change in FOTO score and QTFC and duration of treatment and acuity of condition. The correlation between number of visits and change in FOTO score was also not found to be statistically significant. A linear regression between acuity and change in FOTO score was performed and was statistically significant (r = 0·421, P = 0·003).
Table 3.
Correlations between QTFC and FOTO
| Correlation | Correlation coefficient | Significance (two tailed) |
|---|---|---|
| QTFC and change in FOTO score | −0·123 | 0·401 |
| Number of visits and change in FOTO score | 0·064 | 0·661 |
| Acuity and change in FOTO score | −0·429 | 0·002 |
| Duration and acuity | 0·118 | 0·418 |
| P value (<0·05) |
QTFC: Quebec Task Force Classification; FOTO: focus on therapeutic outcomes.
Discussion
The QTFC and change in FOTO score did not show a significant correlation in this study. This supported other research which found that classifying patients into QTFC categories does not necessarily predict outcome and that patients with LBP may demonstrate improvement regardless of symptom location or assigned QTFC category.6,21
Research by Padfield et al.15 concluded that increasing levels of classification in the QTFC are associated with a poorer prognosis; however, the results of this study did not support this finding. Other research has found a possible correlation between baseline pain and QTFC categories, although limited evidence exists to support QTFC categories as a predictor of outcomes. And other evidence points to patients who were classified according to QTFC categories 3 and 4 were more likely to have higher McGill Pain Questionnaire (MPQ) scores initially.8 Werneke and Hart21 reported pain intensity at the time of discharge from therapy was not predicted by the QTFC. Loisel et al.14 concurred with the results of Werneke and Hart21 and stated pain level scores at discharge, as assessed by the MPQ, ‘were not significantly associated with QTFC categories’.8 This information may indicate a relationship between baseline pain intensity levels and QTFC categories, but the results did not support the predictive validity of the QTFC and pain level change scores.8 In addition, Werneke and Hart21 recommended classifying patients according to non-centralizing or centralizing symptoms and stated that this is more predictive of pain at discharge than using QTF categories 1–4 in patients with acute LBP. Categories of classification that included distal radiating pain or non-centralization of symptoms were found to be a predictor of prolonged disability, or the need for greater number of physical therapy visits.8
The acuity subgroups of QTFC were determined to be a better predictor of outcomes than symptom location or the category number itself. The subgroup b included patients with LBP lasting less than 7 weeks, compared to the subgroup c that included patients with LBP lasting longer than 7 weeks. The subgroup B had a greater average change in FOTO score (22·78) compared to subgroup c (11·99). The improved FOTO score occurred in an average of 42·17 days for subgroup B and 49·2 days for subgroup c. Subgroup b had a greater change in FOTO score with less visits and shorter duration between initial evaluation and discharge. A correlation between acuity and outcomes was found to exist in this study. This finding supports improved outcomes when patients with LBP begin physical therapy in the earlier stages.
This study did not find a correlation between predicted and final FOTO scores because the final FOTO scores improved more than what was predicted. The majority of the PTs participating in this study are certified in Mechanical Diagnosis and Therapy (MDT). Research indicates that a statistically relevant change in FOTO scores is considered an eight-point difference.19 The results from this study found an average change in FOTO score of 17·2 points, in an average of eight treatment visits. This demonstrates significant change in perceived functional status in a mean of eight visits, which is at the lower end of the range of number of visits (8–32) proposed by the Guide to Physical Therapist Practice.20 Classification systems9,11,13 enable PTs to monitor clinical efficiency, such as the number of patient visits and duration of symptoms during an episode of care, and to gage the relationship between treatment strategy and relevant change in functional status.8 The MDT assessment process was described by McKenzie and May,11 and researchers Clare et al.22 provide evidence of construct validity of the MDT assessment. According to the results, patients treated with the use of MDT repeated extension demonstrated greater improvement in lumbar extension active range of motion than in other subgroup classifications. Additionally, the patients who were subgrouped into the derangement classification reported greater perceived recovery than the non-derangement group.22 Additional randomized controlled trials have demonstrated predictive validity of the MDT method of classifying patients with LBP when compared to other treatment procedures.23–25
Limitations
The limitations of this study include, first, the small sample size of 49 participants with non-specific LBP. Second, only one health care system was included, which lessens the external validity attributable to the study. Third, although it is evident that MDT was included among the treatments, PTs likely utilized more than one treatment approach in management.
Conclusion
Quebec Task Force Classification categories and change in FOTO score demonstrated no significant correlation. The results of the study show that patient improvement as per change in FOTO score was related to acuity of symptoms. Further research is warranted to determine a specific classification system that will direct treatment strategies and predict outcomes of patients with non-specific LBP. Low back pain is a common impairment seen in outpatient physical therapy clinics, and it may be noted that the examinations on which MDT was based were found to be efficacious in this small sample.
Disclaimer Statements
Contributors All authors contributed to writing and data analysis.
Funding
Conflicts of interest There are no conflicts of interest related to this study.
Ethics approval This study was reviewed by the Daemen College Human Subjects Research Review Committee.
References
- 1.Hoy DG, Smith E, Cross M, Sanchez-Riera L, Buchbinder R, Blyth FM, et al. . The global burden of musculoskeletal conditions for 2010: an overview of methods. Ann Rheum Dis. 2014;73(6):982–9. [DOI] [PubMed] [Google Scholar]
- 2.Hoy D, Bain C, Williams G, March L, Brooks P, Blyth F, et al. . A systematic review of the global prevalence of low back pain. Ann Rheum Dis. 2012;64(6):2028–37. [DOI] [PubMed] [Google Scholar]
- 3.Deyo R, Mirza S, Martin B. Back pain prevalence and visit rates: estimates from U.S. national surveys, 2002. Spine. 2006;31(23):2724–7. [DOI] [PubMed] [Google Scholar]
- 4.Macfarlane G, Beasley M, Jones E. The prevalence and management of low back pain across adulthood: results from a population-based cross-sectional study (the MUSICIAN study). Pain. 2012;153:27–32. [DOI] [PubMed] [Google Scholar]
- 5.Rubin DI. Epidemiology and risk factors for spine pain. Neurol Clin. 2007;25(2):353–71. [DOI] [PubMed] [Google Scholar]
- 6.Hoy D, Brooks P, Blyth F, Buchbinder R. The epidemiology of low back pain. Best Pract Res Clin Rheumatol. 2010;24(6):769–81. [DOI] [PubMed] [Google Scholar]
- 7.Dobrzykowski EA, Nance T. The focus on therapeutic outcomes (FOTO) outpatient orthopedic rehabilitation database: results of 1994 – 1996. J Rehabil Outcomes Meas. 1997;1(1):56–60. [Google Scholar]
- 8.Werneke MW, Hart D, Oliver D, McGill T, Grigsby D, Ward J, et al. . Prevalence of classification methods for patients with lumbar impairments using the McKenzie syndromes, pain pattern, manipulation and stabilization clinical prediction rules. J Man Manip Ther. 2010;18:197–210. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Fritz K, Delitto A, Erhard R. Comparison of classification-based physical therapy with therapy based on clinical practice guidelines for patients with acute low back pain. Spine. 1993;28(13):1363–72. [DOI] [PubMed] [Google Scholar]
- 10.Fritz J, Cleland J, Childs JD. Subgrouping patients with low back pain: evolution of a classification approach to physical therapy. J Orthop Sports Phys Ther. 2007;37:290–302. [DOI] [PubMed] [Google Scholar]
- 11.McKenzie RA, May S. The lumbar spine: mechanical diagnosis and therapy, 2nd edn. Waikanae, New Zealand: Spinal Publications; 2003. [Google Scholar]
- 12.Spoto MM, Collins J. Physiotherapy diagnosis in clinical practice: a survey of orthopedic certified specialists in the USA. Physiother Res Int. 2008;13(1):31–41. [DOI] [PubMed] [Google Scholar]
- 13.Van Dillen LR, Sahrmann SA, Norton BJ, Caldwell CA, McDonnell MK, Bloom NJ. Movement system impairment-based categories for low back pain: stage 1 validation. J Orthop Sports Phys Ther. 2003;33(3):126–42. [DOI] [PubMed] [Google Scholar]
- 14.Loisel P, Vachon B, Lemaire J, Durand MJ, Poitras S, Stock S, et al. . Discriminative and predictive validity assessment of the Quebec task force classification. Spine. 2002;27(8):851–7. [DOI] [PubMed] [Google Scholar]
- 15.Padfield B, Chesworth B, Butler B. Use of an outcome measurement system to answer a clinical question: is the Quebec task force classification system useful in an outpatient setting? Physiother Canada. 2002;54(4):258–64. [Google Scholar]
- 16.Atlas SJ, Deyo RA, Patrick DL, Convery K, Keller RB, Singer DE. The Quebec task force classification for spinal disorders and the severity, treatment, and outcomes of sciatica and lumbar spinal stenosis. Spine. 1996;21(24):2885–92. [DOI] [PubMed] [Google Scholar]
- 17.Badke MB, Boissonnault WG. Changes in disability following physical therapy intervention for patients with low back pain: dependence on symptom duration. Arch Phys Med Rehabil. 2006;87(6):749–56. [DOI] [PubMed] [Google Scholar]
- 18.Kongsted A, Kent P, Manniche C. Prognostic implications of the Quebec task force classification of back-related leg pain: an analysis of longitudinal routine clinical data. BMC Musculoskel Disord. 2013;14(1):171. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Wang YC, Hart DL, Werneke M, Stratford PW, Mioduski JE. Clinical interpretation of outcomes measures generated from a lumbar computerized adaptive test. Phys Ther. 2010;90(9):1323–35. [DOI] [PubMed] [Google Scholar]
- 20.American Physical Therapy Association Guide to physical therapist practice, Revised 2nd edn. Alexandria, VA: American Physical Therapy Association; 2003. ‘ISBN-10: 1887759859’. [Google Scholar]
- 21.Werneke MW, Hart DL. Categorizing patients with occupational low back pain by use of the Quebec task force classification system versus pain pattern classification procedures: discriminant and predictive validity. Phys Ther. 2004;84(3):243–54. [PubMed] [Google Scholar]
- 22.Clare HA, Adams R, Maher CG. Construct validity of lumbar extension measures in McKenzie's derangement syndrome. Man Ther. 2007;12(4):328–34. [DOI] [PubMed] [Google Scholar]
- 23.Petersen T, Kryger P, Ekdahl C, Olsen S, Jacobsen S. The effect of McKenzie therapy as compared with that of intensive strengthening training for the treatment of patients with sub-acute or chronic low back pain: a randomized controlled trial. Spine. 2002;27(16):1702–9. [DOI] [PubMed] [Google Scholar]
- 24.Stankovic R, Johnell O. Conservative treatment of acute low-back pain. A prospective randomized trial: McKenzie method of treatment versus patient education in mini back school. Spine. 1990;15:120–3. [PubMed] [Google Scholar]
- 25.Miller ER, Scherk RJ, Karnes JL, Rousselle RG. A comparison of the Mekenzie approach to a specific spine stabilization program for chronic low back pain. J. Man Manip. Thes. 2005;13(2):103–112. [Google Scholar]