title: Validation of the Patient Global Impression scales for use in detrusor overactivity: secondary analysis of the RELAX study.
abstract: OBJECTIVE
  To assess construct validity of the Patient Global Impression scales (Severity [PGI-S], Bother [PGI-B] and Improvement [PGI-I]) for symptoms of detrusor overactivity (DO).
  
  
  METHODS
  Secondary analysis of a randomised trial of onabotulinum toxin A.
  
  
  METHODS
  Eight UK urogynaecology departments.
  
  
  METHODS
  A total of 240 women with DO refractory to medical treatment randomised to receive 200 iu onabotulinum toxin A or placebo in the RELAX trial and followed up for 6 months.
  
  
  METHODS
  Urinary diaries and disease-specific quality of life (QoL) questionnaires were completed at baseline and during follow up. Discriminatory ability of the PGI-S, PGI-B and PGI-I scales to identify symptom severity and change in severity was assessed by comparing mean diary and QoL outcomes across the response categories, analysed by one-way analysis of variance.
  
  
  RESULTS
  Data were available from 237 women (98.8%) for validation of PGI-S and PGI-B at baseline, and 192 women (80%) at 6 weeks follow up for validation of PGI-I. Leakage episodes (P = 0.01), urgency episodes (P = 0.019), urgency severity (P = 0.012), and QoL scores (all P < 0.001) were greater in women with more severe problems on PGI-S. Similar results were seen for PGI-B: leakage (P = 0.051), urgency episodes (P < 0.001), urgency severity (P < 0.001), and QoL scores (all P < 0.001). PGI-I responses demonstrated significant relationships with size of change of all variables (P < 0.001). The generic instrument EQ-5D had weaker relationships (PGI-S, P = 0.09; PGI-B, P = 0.004; PGI-I, P = 0.06), suggesting that it was less sensitive.
  
  
  CONCLUSIONS
  The PGI scales are robust and valid instruments to assess disease severity, bother and improvement after treatment in women with detrusor overactivity.
authors.affiliation: Reproductive Sciences Section, CSMM, University of Leicester, Leicester, UK.
authors.forename: D G
authors.initials: DG
authors.lastname: Tincello
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: R K
authors.initials: RK
authors.lastname: Owen
authors.affiliation: Addenbrookes' Hospital, Cambridge, UK.
authors.forename: M C
authors.initials: MC
authors.lastname: Slack
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: K R
authors.initials: KR
authors.lastname: Abrams
mesh_terms: D000704:Analysis of Variance; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D011788:Quality of Life; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D053201:Urinary Bladder, Overactive / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A