title: Trajectories of symptoms and function in older adults with low back disorders.
abstract: METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To determine whether there are distinct trajectories of back pain and function among older adults and to identify characteristics that distinguish among patients with substantially different prognoses.
  
  
  BACKGROUND
  Although the differential diagnosis and course of low back pain among older adults may differ from middle-aged adults, there is little evidence. Better understanding variability in recovery among older adults may help target patients for more intensive clinical interventions, plan resource use, and design clinical studies of more homogeneous patient groups.
  
  
  METHODS
  Patients aged 65 years or older with a new episode of care for back pain were recruited at 3 geographically diverse sites. Patients completed pain intensity and Roland-Morris Disability measures at baseline and 3, 6, and 12 months later. We used latent class analysis to identify distinct trajectories of pain and function and then logistic regression to identify predictors of membership in the improving trajectories.
  
  
  RESULTS
  There were 3929 participants who completed outcome measures at every follow-up interval. Latent class analysis identified subgroups with low, intermediate, or high pain or disability scores who remained relatively stable over time. However, small subgroups showed dramatic improvement from baseline to 1 year (17% with major improvement in Roland score, pain intensity, or both). Shorter pain duration, higher patient confidence in improvement, and fewer comorbid conditions at baseline were each associated independently with favorable prognosis.
  
  
  CONCLUSIONS
  Although most patients remained relatively stable over a year, latent class analysis identified small groups with major improvement in pain, function, or both. This technique may, therefore, be useful for studying back pain prognosis. Our results should help assemble more prognostically homogeneous groups for research, and the technique may help identify subgroups of patients with uniquely successful responses to investigational interventions.
  
  
  METHODS
  3.
authors.affiliation: *Departments of Family Medicine, Medicine, and Public Health and Preventive Medicine, and the Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR †Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA; Departments of ‡Biostatistics §Psychiatry and Behavioral Sciences, and ¶Rehabilitation Medicine, Comparative Effectiveness, Cost and Outcomes Research Center, University of Washington, Seattle, WA ‖Division of Research, Northern California Kaiser-Permanente, Oakland, CA **Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Spine Unit, Harvard Vanguard Medical Associates, Boston, MA ††Neuroscience Institute, Henry Ford Hospital, Detroit, MI; and ‡‡Departments of Radiology, Neurological Surgery, and Health Services, Comparative Effectiveness, Cost and Outcomes Research Center, University of Washington, Seattle, WA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Deyo
authors.forename: Matthew
authors.initials: M
authors.lastname: Bryan
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Comstock
authors.forename: Judith A
authors.initials: JA
authors.lastname: Turner
authors.forename: Patrick
authors.initials: P
authors.lastname: Heagerty
authors.forename: Janna
authors.initials: J
authors.lastname: Friedly
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Avins
authors.forename: Srdjan S
authors.initials: SS
authors.lastname: Nedeljkovic
authors.forename: David R
authors.initials: DR
authors.lastname: Nerenz
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Jarvik
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000534:rehabilitation; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D010147:Pain Measurement; D011379:Prognosis; D011446:Prospective Studies; D016896:Treatment Outcome