title: Can patient characteristics predict benefit from epidural corticosteroid injections for lumbar spinal stenosis symptoms?
abstract: BACKGROUND
  Epidural corticosteroid injections are commonly used to treat back and leg pain associated with lumbar spinal stenosis. However, little is known about which patient characteristics may predict favorable responses.
  
  
  OBJECTIVE
  The aim was to identify patient characteristics associated with benefits from epidural injections of corticosteroid with lidocaine versus epidural injections of lidocaine only for lumbar spinal stenosis symptoms.
  
  
  METHODS
  This was a secondary analysis of Lumbar Epidural steroid injections for Spinal Stenosis randomized controlled trial data from 16 US clinical sites.
  
  
  METHODS
  Patients aged older than or equal to 50 years with moderate-to-severe leg pain and lumbar central spinal stenosis randomized to epidural injections of corticosteroids with lidocaine (n=200) or lidocaine only (n=200) were included.
  
  
  METHODS
  Primary outcomes were the Roland-Morris Disability Questionnaire (RMDQ) and 0 to 10 leg pain intensity ratings. Secondary outcomes included the Brief Pain Inventory Interference Scale and the Swiss Spinal Stenosis Questionnaire.
  
  
  METHODS
  At baseline, clinicians rated severity of patient spinal stenosis, and patients completed predictor and outcome measures. Patients completed outcome measures again 3 and 6 (primary end point) weeks after randomization/initial injection. Analysis of covariance was used with treatment by covariate interactions to identify baseline predictors of greater benefit from corticosteroid+lidocaine versus lidocaine alone. We also identified nonspecific (independent of treatment) predictors of outcomes.
  
  
  RESULTS
  Among 21 candidate predictors and six outcomes, only one baseline variable predicted greater benefit from corticosteroid+lidocaine versus lidocaine only at 3 or 6 weeks. Compared with patients who rated their health-related quality of life as high on the EQ-5D Index, patients who rated it as poor had greater improvement with corticosteroid than with lidocaine only in leg pain at 6 (but not 3) weeks (interaction coefficient=2.94; 95% confidence interval [CI]=0.11-5.76; p=.04) and in RMDQ disability scores at 3 (but not 6) weeks (interaction coefficient=4.77, 95% CI= -0.04 to 9.59; p = .05). Several baseline patient characteristics predicted outcomes regardless of treatment assignment.
  
  
  CONCLUSIONS
  Among 21 baseline patient characteristics examined, none, including clinician-rated spinal stenosis severity, were consistent predictors of benefit from epidural injections of lidocaine+corticosteroid versus lidocaine only.
authors.affiliation: Department of Psychiatry & Behavioral Sciences, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA; Department of Rehabilitation Medicine, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA. Electronic address: jturner@uw.edu.
authors.forename: Judith A
authors.initials: JA
authors.lastname: Turner
authors.affiliation: Department of Biostatistics, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Comstock
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Standaert
authors.affiliation: Department of Biostatistics, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Heagerty
authors.affiliation: Department of Radiology, University of Washington, Box 359728, 325 Ninth Ave, Seattle, WA 98104-2499, USA; Department of Health Services, University of Washington, Box 359728, 325 Ninth Ave, Seattle, WA 98104-2499, USA; Department of Neurological Surgery, University of Washington, Box 359728, 325 Ninth Ave, Seattle, WA 98104-2499, USA.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Jarvik
authors.affiliation: Department of Family Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA; Department of Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA; Department of Public Health and Preventive Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA; Oregon Institute for Occupational Health Sciences, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Deyo
authors.affiliation: Department of Anesthesiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA 15213, USA; Department of Psychiatry, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213, USA.
authors.forename: Ajay D
authors.initials: AD
authors.lastname: Wasan
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Spine Unit, Harvard Vanguard Medical Associates, BWH Pain Management Center, 850 Boylston St, Chestnut Hill, MA 02467, USA.
authors.forename: Srdjan S
authors.initials: SS
authors.lastname: Nedeljkovic
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA.
authors.forename: Janna L
authors.initials: JL
authors.lastname: Friedly
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007268:Injections, Epidural; D008297:Male; D008875:Middle Aged; D059408:Pain Management / Q000009:adverse effects* / Q000706:statistics & numerical data; D016032:Randomized Controlled Trials as Topic; D013130:Spinal Stenosis / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D000305:Adrenal Cortex Hormones
keywords: Back pain; Corticosteroid; Epidural steroid injections; Leg pain; Lumbar spinal stenosis; Predictors; Treatment effect modifiers