title: Influence of the mental health status on a new measure of objective functional impairment in lumbar degenerative disc disease.
abstract: The Timed Up and Go (TUG) test has recently been proposed as a simple and standardized measure for objective functional impairment (OFI) in patients with lumbar degenerative disc disease (DDD).
  
  
  
  The study aimed to explore the relationship between a patient's mental health status and both patient-reported outcome measures (PROMs) and TUG test results.
  
  
  
  This is a prospective institutional review board-approved two-center study.
  
  
  
  The sample was composed of 375 consecutive patients scheduled for lumbar spine surgery and a healthy cohort of 110 control subjects.
  
  
  
  Patients and control subjects were assessed with the TUG test and a comprehensive panel of subjective PROMs of pain intensity (visual analog scale [VAS]), functional impairment (Roland-Morris Disability Index [RMDI]), Oswestry Disability Index [ODI]), as well as health-related quality of life (hrQoL; Euro-Qol [EQ]-5D).
  
  
  
  Standardized age- and sex-adjusted TUG test T-scores were calculated. The dependent variable was the short-form (SF)-12 mental component summary (MCS) quartiles, and the independent variables were the TUG T-scores and PROMs. Direct and adjusted analyses of covariance were performed to estimate the interaction between the SF-12 MCS quartiles and the independent variables.
  
  
  
  In patients, there was a significant decrease in the subjective PROMs, notably the VAS back pain (p=.001) and VAS leg pain (p=.035), as well as significant increase in the RMDI (p<.001), ODI (p<.001), and the EQ-5D index (p<.001) with every increase in the quartile of the SF-12 MCS. There were no significant group differences of OFI as measured by the TUG T-scores across the SF-12 MCS quartiles (p=.462). In the healthy control group, a significant decrease in VAS leg pain (p=.028), RMDI (p=.013), and ODI (p<.001), as well as a significant increase in the EQ-5D index (p<.001), was seen across the SF-12 MCS quartiles, whereas TUG T-scores remained stable (p=.897).
  
  
  
  There are significant influences of mental hrQoL on subjective measures of pain, functional impairment, and hrQoL that might lead to bias when evaluating patients with lumbar DDD who suffer from reduced mental hrQoL. The TUG test appears to be a stable instrument and especially helpful in the evaluation of patients with lumbar DDD and mental health problems.
authors.affiliation: Department of Neurosurgery and Faculty of Medicine, University Hospital Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland; Department of Neurosurgery, University Hospital Zurich, Frauenklinikstrasse 10, 8091 Zurich, Switzerland. Electronic address: mnstienen@gmail.com.
authors.forename: Martin N
authors.initials: MN
authors.lastname: Stienen
authors.affiliation: School of Medicine and Public Health, University of Newcastle, University Drive, Callaghan, Newcastle, NSW 2308, Australia.
authors.forename: Nicolas R
authors.initials: NR
authors.lastname: Smoll
authors.affiliation: Department of Neurosurgery, Cantonal Hospital St. Gallen, Rorschach Str. 95, 9007 St. Gallen, Switzerland.
authors.forename: Holger
authors.initials: H
authors.lastname: Joswig
authors.affiliation: Department of General Psychology: Cognition, University of Duisburg-Essen Duisburg, Forsthausweg 2, 47048 Duisburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Snagowski
authors.affiliation: Department of Neurosurgery and Faculty of Medicine, University Hospital Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
authors.forename: Marco V
authors.initials: MV
authors.lastname: Corniola
authors.affiliation: Department of Neurosurgery and Faculty of Medicine, University Hospital Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
authors.forename: Karl
authors.initials: K
authors.lastname: Schaller
authors.affiliation: Department of Neurosurgery, Cantonal Hospital St. Gallen, Rorschach Str. 95, 9007 St. Gallen, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hildebrandt
authors.affiliation: Department of Neurosurgery and Faculty of Medicine, University Hospital Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
authors.forename: Oliver P
authors.initials: OP
authors.lastname: Gautschi
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis* / Q000523:psychology; D008159:Lumbar Vertebrae / Q000473:pathology*; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D009460:Neurologic Examination / Q000379:methods / Q000592:standards*; D000071066:Patient Reported Outcome Measures; D011788:Quality of Life; D015599:Trauma Severity Indices
keywords: Degenerative disc disease; Depression; Health-related quality of life; Mental health; Objective functional impairment; Timed Up and Go test