Effect of Low Back Pain Chronicity on Patient Outcomes Treated in Outpatient Physical Therapy: A Retrospective Observational Study

Published:December 21, 2019DOI:



      To examine the potential relationship between physical therapy (PT) treatment outcomes and chronicity of low back pain (LBP) in the outpatient setting.


      Retrospective observational study.


      Outpatient PT clinics across 11 states.


      A total of 11,941 patients with LBP provided with PT services and discharged from care between January 1, 2017, and December 31, 2018.

      Main Outcome Measures

      Focus on Therapeutic Outcome Low Back Functional Status (FS) Patient-Reported Outcome Measure (PROM) was the primary outcomes measure used. It assesses the patients’ perceived physical abilities for patients experiencing LBP impairments. It determined a functional score on a linear metric ranging from 0 (low functioning) to 100 (high functioning). The difference in score between the intake FS and final FS score produced the FS change, which represented the overall improvement of the episode of care.


      The mean FS change was 16.997 (n=11,945). Patients with chronic symptoms (>90-d duration) had an FS change of 15.920 (n=7264) across 14.63 visits. Patients with subacute symptoms (15-90d) had an FS change of 21.66 (n=3631) across 14.05. Patients with acute symptoms (0-14d) had an FS change of 29.32 (n=1050) across 13.66 visits. Stepwise regression analysis revealed a significant â for chronicity (−4.155) with all models.


      Overall, this study shows patients experiencing shorter duration of LBP symptoms before starting a PT episode of care experience significantly better outcomes than patients who waited. Furthermore, the number of treatment session and duration of care was similar between groups, indicating potential ineffective or insufficient care was provided for patients with chronic pain.


      List of abbreviations:

      AIC (Akaike information criterion), BIC (Bayesian information criterion), LBP (low back pain), FOTO (Focus on Therapeutic Outcomes), FS (functional status), PT (physical therapy), PROM (patient-reported outcome measure)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Archives of Physical Medicine and Rehabilitation
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Meucci R.D.
        • Fassa A.G.
        • Faria N.M.
        Prevalence of chronic low back pain: systematic review.
        Rev Saude Publica. 2015; 49
        • Melloh M.
        • Roder C.
        • Elfering A.
        • et al.
        Differences across health care systems in outcome and cost-utility of surgical and conservative treatment of chronic low back pain: a study protocol.
        BMC Musculoskelet Disord. 2008; 9: 81
        • Mafi J.N.
        • McCarthy E.P.
        • Davis R.B.
        • Landon B.E.
        Worsening trends in the management and treatment of back pain.
        JAMA Intern Med. 2013; 173: 1573-1581
        • Yang H.
        • Haldeman S.
        • Lu M.L.
        • Baker D.
        Low back pain prevalence and related workplace psychosocial risk factors: a study using data from the 2010 National Health Interview Survey.
        J Manipulative Physiol Ther. 2016; 39: 459-472
        • Volker G.
        • van Vree F.
        • Wolterbeek R.
        • et al.
        Long-term outcomes of multidisciplinary rehabilitation for chronic musculoskeletal pain.
        Musculoskeletal Care. 2017; 15: 59-68
        • Beattie P.F.
        • Silfies S.P.
        • Jordon M.
        The evolving role of physical therapists in the long-term management of chronic low back pain: longitudinal care using assisted self-management strategies.
        Braz J Phys Ther. 2016; 20: 580-591
        • Main C.J.
        • Foster N.
        • Buchbinder R.
        How important are back pain beliefs and expectations for satisfactory recovery from back pain?.
        Best Pract Res Clin Rheumatol. 2010; 24: 205-217
        • Grotle M.
        • Foster N.E.
        • Dunn K.M.
        • Croft P.
        Are prognostic indicators for poor outcome different for acute and chronic low back pain consulters in primary care?.
        Pain. 2010; 151: 790-797
        • Pengel L.H.
        • Refshauge K.M.
        • Maher C.G.
        • Nicholas M.K.
        • Herbert R.D.
        • McNair P.
        Physiotherapist-directed exercise, advice, or both for subacute low back pain: a randomized trial.
        Ann Intern Med. 2007; 146: 787-796
        • Smith B.E.
        • Littlewood C.
        • May S.
        An update of stabilisation exercises for low back pain: a systematic review with meta-analysis.
        BMC Musculoskelet Disord. 2014; 15: 416
        • Searle A.
        • Spink M.
        • Ho A.
        • Chuter V.
        Exercise interventions for the treatment of chronic low back pain: a systematic review and meta-analysis of randomised controlled trials.
        Clin Rehabil. 2015; 29: 1155-1167
        • Steffens D.
        • Maher C.G.
        • Pereira L.S.
        • et al.
        Prevention of low back pain: a systematic review and meta-analysis.
        JAMA Intern Med. 2016; 176: 199-208
        • Furlan A.D.
        • Yazdi F.
        • Tsertsvadze A.
        • et al.
        A systematic review and meta-analysis of efficacy, cost-effectiveness, and safety of selected complementary and alternative medicine for neck and low-back pain.
        Evid Based Complement Alternat Med. 2012; 2012: 953139
        • Macedo L.G.
        • Bostick G.P.
        • Maher C.G.
        Exercise for prevention of recurrences of nonspecific low back pain.
        Phys Ther. 2013; 93: 1587-1591
        • van Middelkoop M.
        • Rubinstein S.M.
        • Kuijpers T.
        • et al.
        A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain.
        Eur Spine J. 2011; 20: 19-39
        • van Tulder M.W.
        • Koes B.W.
        • Bouter L.M.
        Conservative treatment of acute and chronic nonspecific low back pain. A systematic review of randomized controlled trials of the most common interventions.
        Spine (Phila Pa 1976). 1997; 22: 2128-2156
        • Beattie P.F.
        • Silfies S.P.
        Improving long-term outcomes for chronic low back pain: time for a new paradigm?.
        J Orthop Sports Phys Ther. 2015; 45: 236-239
        • Hayden J.A.
        • van Tulder M.W.
        • Tomlinson G.
        Systematic review: strategies for using exercise therapy to improve outcomes in chronic low back pain.
        Ann Intern Med. 2005; 142: 776-785
        • Beneck G.J.
        • Kulig K.
        Multifidus atrophy is localized and bilateral in active persons with chronic unilateral low back pain.
        Arch Phys Med Rehabil. 2012; 93: 300-306
        • Hicks G.E.
        • Simonsick E.M.
        • Harris T.B.
        • et al.
        Trunk muscle composition as a predictor of reduced functional capacity in the health, aging and body composition study: the moderating role of back pain.
        J Gerontol A Biol Sci Med Sci. 2005; 60: 1420-1424
        • Kulig K.
        • Scheid A.R.
        • Beauregard R.
        • Popovich Jr., J.M.
        • Beneck G.J.
        • Colletti P.M.
        Multifidus morphology in persons scheduled for single-level lumbar microdiscectomy: qualitative and quantitative assessment with anatomical correlates.
        Am J Phys Med Rehabil. 2009; 88: 355-361
        • Pelletier R.
        • Higgins J.
        • Bourbonnais D.
        Addressing neuroplastic changes in distributed areas of the nervous system associated with chronic musculoskeletal disorders.
        Phys Ther. 2015; 95: 1582-1591
        • Hodges P.W.
        • Tucker K.
        Moving differently in pain: a new theory to explain the adaptation to pain.
        Pain. 2011; 152: 90-98
        • Bohman T.
        • Alfredsson L.
        • Jensen I.
        • Hallqvist J.
        • Vingard E.
        • Skillgate E.
        Does a healthy lifestyle behaviour influence the prognosis of low back pain among men and women in a general population? A population-based cohort study.
        BMJ Open. 2014; 4e005713
        • Flanagan S.P.
        • Kulig K.
        • Clinresnet P.
        Time courses of adaptation in lumbar extensor performance of patients with a single-level microdiscectomy during a physical therapy exercise program.
        J Orthop Sports Phys Ther. 2010; 40: 336-344
        • Matthias M.S.
        • Miech E.J.
        • Myers L.J.
        • Sargent C.
        • Bair M.J.
        “There's more to this pain than just pain”: how patients' understanding of pain evolved during a randomized controlled trial for chronic pain.
        J Pain. 2012; 13: 571-578
        • Flor H.
        • Braun C.
        • Elbert T.
        • Birbaumer N.
        Extensive reorganization of primary somatosensory cortex in chronic back pain patients.
        Neurosci Lett. 1997; 224: 5-8
        • Crozier J.
        • Roig M.
        • Eng J.J.
        • et al.
        High-intensity interval training after stroke: an opportunity to promote functional recovery, cardiovascular health, and neuroplasticity.
        Neurorehabil Neural Repair. 2018; 32: 543-556
        • Husby V.S.
        • Foss O.A.
        • Husby O.S.
        • Winther S.B.
        Randomized controlled trial of maximal strength training vs. standard rehabilitation following total knee arthroplasty.
        Eur J Phys Rehabil Med. 2018; 54: 371-379
        • Segura-Jimenez V.
        • Estevez-Lopez F.
        • Castro-Pinero J.
        • et al.
        Association of patterns of moderate-to-vigorous physical activity bouts with pain, physical fatigue, and disease severity in women with fibromyalgia: the al-Andalus Project.
        Arch Phys Med Rehabil. 2019; 100: 1234-1242
        • Gordon R.
        • Bloxham S.
        A systematic review of the effects of exercise and physical activity on non-specific chronic low back pain.
        Healthcare (Basel). 2016; 4
        • Verbrugghe J.
        • Agten A.
        • Stevens S.
        • et al.
        Exercise intensity matters in chronic nonspecific low back pain rehabilitation.
        Med Sci Sports Exerc. 2019; 51: 2434-2442
        • Colberg S.R.
        • Swain D.P.
        • Vinik A.I.
        Use of heart rate reserve and rating of perceived exertion to prescribe exercise intensity in diabetic autonomic neuropathy.
        Diabetes Care. 2003; 26: 986-990
        • Seo D.I.
        • Kim E.
        • Fahs C.A.
        • et al.
        Reliability of the one-repetition maximum test based on muscle group and gender.
        J Sports Sci Med. 2012; 11: 221-225
        • Lorenz D.
        • Morrison S.
        Current concepts in periodization of strength and conditioning for the sports physical therapist.
        Int J Sports Phys Ther. 2015; 10: 734-747
        • Reiman M.P.
        • Lorenz D.S.
        Integration of strength and conditioning principles into a rehabilitation program.
        Int J Sports Phys Ther. 2011; 6: 241-253
        • Westcott W.L.
        Resistance training is medicine: effects of strength training on health.
        Curr Sports Med Rep. 2012; 11: 209-216
        • Soderstrom N.C.
        • Bjork R.A.
        Learning versus performance: an integrative review.
        Perspect Psychol Sci. 2015; 10: 176-199
        • Deutscher D.
        • Horn S.D.
        • Dickstein R.
        • et al.
        Associations between treatment processes, patient characteristics, and outcomes in outpatient physical therapy practice.
        Arch Phys Med Rehabil. 2009; 90: 1349-1363
        • Apkarian A.V.
        • Baliki M.N.
        • Farmer M.A.
        Predicting transition to chronic pain.
        Curr Opin Neurol. 2013; 26: 360-367
        • Resnik L.
        • Liu D.
        • Mor V.
        • Hart D.L.
        Predictors of physical therapy clinic performance in the treatment of patients with low back pain syndromes.
        Phys Ther. 2008; 88: 989-1004
        • Swinkels I.C.
        • Wimmers R.H.
        • Groenewegen P.P.
        • van den Bosch W.J.
        • Dekker J.
        • van den Ende C.H.
        What factors explain the number of physical therapy treatment sessions in patients referred with low back pain; a multilevel analysis.
        BMC Health Serv Res. 2005; 5: 74
        • Hart D.L.
        The power of outcomes: FOTO Industrial Outcomes Tool -- initial assessment.
        Work. 2001; 16: 39-51
        • Hart D.L.
        • Wang Y.C.
        • Stratford P.W.
        • Mioduski J.E.
        Computerized adaptive test for patients with knee impairments produced valid and responsive measures of function.
        J Clin Epidemiol. 2008; 61: 1113-1124
        • Hart D.L.
        • Werneke M.W.
        • Wang Y.C.
        • Stratford P.W.
        • Mioduski J.E.
        Computerized adaptive test for patients with lumbar spine impairments produced valid and responsive measures of function.
        Spine (Phila Pa 1976). 2010; 35: 2157-2164
      1. International Classification of Functioning, Disability and Health: ICF. World Health Organization, Geneva2001
        • Hart D.L.
        • Mioduski J.E.
        • Werneke M.W.
        • Stratford P.W.
        Simulated computerized adaptive test for patients with lumbar spine impairments was efficient and produced valid measures of function.
        J Clin Epidemiol. 2006; 59: 947-956
        • Wand B.M.
        • Bird C.
        • McAuley J.H.
        • Dore C.J.
        • MacDowell M.
        • De Souza L.H.
        Early intervention for the management of acute low back pain: a single-blind randomized controlled trial of biopsychosocial education, manual therapy, and exercise.
        Spine (Phila Pa 1976). 2004; 29: 2350-2356
        • Gellhorn A.C.
        • Chan L.
        • Martin B.
        • Friedly J.
        Management patterns in acute low back pain: the role of physical therapy.
        Spine (Phila Pa 1976). 2012; 37: 775-782
        • Childs J.D.
        • Fritz J.M.
        • Wu S.S.
        • et al.
        Implications of early and guideline adherent physical therapy for low back pain on utilization and costs.
        BMC Health Serv Res. 2015; 15: 150
        • Fritz J.M.
        • Magel J.S.
        • McFadden M.
        • et al.
        Early physical therapy vs usual care in patients with recent-onset low back pain: a randomized clinical trial.
        JAMA. 2015; 314: 1459-1467
        • Fritz J.M.
        • Childs J.D.
        • Wainner R.S.
        • Flynn T.W.
        Primary care referral of patients with low back pain to physical therapy: impact on future health care utilization and costs.
        Spine (Phila Pa 1976). 2012; 37: 2114-2121
        • Bushnell M.C.
        • Ceko M.
        • Low L.A.
        Cognitive and emotional control of pain and its disruption in chronic pain.
        Nat Rev Neurosci. 2013; 14: 502-511
        • Hanney W.J.
        • Masaracchio M.
        • Liu X.
        • Kolber M.J.
        The influence of physical therapy guideline adherence on healthcare utilization and costs among patients with low back pain: a systematic review of the literature.
        PLoS One. 2016; 11e0156799
        • Frogner B.K.
        • Harwood K.
        • Andrilla C.H.A.
        • Schwartz M.
        • Pines J.M.
        Physical therapy as the first point of care to treat low back pain: an instrumental variables approach to estimate impact on opioid prescription, health care utilization, and costs.
        Health Serv Res. 2018; 53: 4629-4646
        • Thackeray A.
        • Hess R.
        • Dorius J.
        • Brodke D.
        • Fritz J.
        Relationship of opioid prescriptions to physical therapy referral and participation for medicaid patients with new-onset low back pain.
        J Am Board Fam Med. 2017; 30: 784-794
        • Boissonnault W.G.
        • Badke M.B.
        Influence of acuity on physical therapy outcomes for patients with cervical disorders.
        Arch Phys Med Rehabil. 2008; 89: 81-86
        • Shipton E.A.
        Physical therapy approaches in the treatment of low back pain.
        Pain Ther. 2018; 7: 127-137
        • Wilkens P.
        • Scheel I.B.
        • Grundnes O.
        • Hellum C.
        • Storheim K.
        Prognostic factors of prolonged disability in patients with chronic low back pain and lumbar degeneration in primary care: a cohort study.
        Spine (Phila Pa 1976). 2013; 38: 65-74
        • Crombez G.
        • Van Damme S.
        • Eccleston C.
        Hypervigilance to pain: an experimental and clinical analysis.
        Pain. 2005; 116: 4-7
        • Sullivan M.J.
        • Stanish W.
        • Waite H.
        • Sullivan M.
        • Tripp D.A.
        Catastrophizing, pain, and disability in patients with soft-tissue injuries.
        Pain. 1998; 77: 253-260
        • Asmundson G.J.
        • Katz J.
        Understanding the co-occurrence of anxiety disorders and chronic pain: state-of-the-art.
        Depress Anxiety. 2009; 26: 888-901
        • Gatchel R.J.
        • Bernstein D.
        • Stowell A.W.
        • Pransky G.
        Psychosocial differences between high-risk acute vs. chronic low back pain patients.
        Pain Pract. 2008; 8: 91-97
        • Woby S.R.
        • Urmston M.
        • Watson P.J.
        Self-efficacy mediates the relation between pain-related fear and outcome in chronic low back pain patients.
        Eur J Pain. 2007; 11: 711-718
        • Waddell G.
        • Newton M.
        • Henderson I.
        • Somerville D.
        • Main C.J.
        A Fear-Avoidance Beliefs Questionnaire (FABQ) and the role of fear-avoidance beliefs in chronic low back pain and disability.
        Pain. 1993; 52: 157-168
        • Lumley M.A.
        • Cohen J.L.
        • Borszcz G.S.
        • et al.
        Pain and emotion: a biopsychosocial review of recent research.
        J Clin Psychol. 2011; 67: 942-968
        • May S.
        Patients' attitudes and beliefs about back pain and its management after physiotherapy for low back pain.
        Physiother Res Int. 2007; 12: 126-135
        • Bialosky J.E.
        • Bishop M.D.
        • Cleland J.A.
        Individual expectation: an overlooked, but pertinent, factor in the treatment of individuals experiencing musculoskeletal pain.
        Phys Ther. 2010; 90: 1345-1355
        • Cao H.
        • Gao Y.J.
        • Ren W.H.
        • et al.
        Activation of extracellular signal-regulated kinase in the anterior cingulate cortex contributes to the induction and expression of affective pain.
        J Neurosci. 2009; 29: 3307-3321
        • Beneciuk J.M.
        • Bishop M.D.
        • Fritz J.M.
        • et al.
        The STarT back screening tool and individual psychological measures: evaluation of prognostic capabilities for low back pain clinical outcomes in outpatient physical therapy settings.
        Phys Ther. 2013; 93: 321-333
        • Delitto A.
        • George S.Z.
        • Van Dillen L.
        • et al.
        Low back pain.
        J Orthop Sports Phys Ther. 2012; 42: 1-57
        • Shmagel A.
        • Foley R.
        • Ibrahim H.
        Epidemiology of chronic low back pain in US adults: data from the 2009-2010 National Health and Nutrition Examination Survey.
        Arthritis Care Res (Hoboken). 2016; 68: 1688-1694
        • Freburger J.K.
        • Holmes G.M.
        • Agans R.P.
        • et al.
        The rising prevalence of chronic low back pain.
        Arch Intern Med. 2009; 169: 251-258
        • Pylypchuk Y.
        • Sarpong E.M.
        Comparison of health care utilization: United States versus Canada.
        Health Serv Res. 2013; 48: 560-581
        • Gaskin D.J.
        • Richard P.
        The economic costs of pain in the United States.
        J Pain. 2012; 13: 715-724
        • Papanicolas I.
        • Woskie L.R.
        • Jha A.K.
        Health care spending in the United States and other high-income countries.
        JAMA. 2018; 319: 1024-1039
        • Liu X.
        • Hanney W.J.
        • Masaracchio M.
        • et al.
        Immediate physical therapy initiation in patients with acute low back pain is associated with a reduction in downstream health care utilization and costs.
        Phys Ther. 2018; 98: 336-347
        • Hartvigsen J.
        • Hancock M.J.
        • Kongsted A.
        • et al.
        What low back pain is and why we need to pay attention.
        Lancet. 2018; 391: 2356-2367
        • Fritz J.M.
        • Cleland J.A.
        • Speckman M.
        • Brennan G.P.
        • Hunter S.J.
        Physical therapy for acute low back pain: associations with subsequent healthcare costs.
        Spine (Phila Pa 1976). 2008; 33: 1800-1805
        • Harned M.
        • Sloan P.
        Safety concerns with long-term opioid use.
        Expert Opin Drug Saf. 2016; 15: 955-962
        • White J.M.
        Pleasure into pain: the consequences of long-term opioid use.
        Addict Behav. 2004; 29: 1311-1324