title: International Prostate Symptom Score Should Be Considered a Complement Rather Than a Substitute to Generic Preference-Based Measures for Measuring Lower Urinary Tract Symptoms Within Economic Evaluation.
abstract: OBJECTIVE
  To determine the suitability of using the International Prostate Symptom Score (IPSS), a condition-specific instrument, within economic evaluation of lower urinary tract symptom (LUTS) interventions.
  
  
  METHODS
  Data were obtained from a cohort of 2236 community-dwelling Australian men. Using correlations and a modified Bland-Altman plot, we investigated the convergent validity of the IPSS with two generic quality of life (GQol) instruments: the Assessment of Quality of Life 4 Dimensions (AQoL-4D) and the Short-Form 36 (SF-36). Discriminant validity was investigated using Wilcoxon-Mann-Whitney and Kruskal-Wallis tests, comparing instrument scores and utilities between subgroups varying in age, marital status, history of illness, smoking status and self-assessed general health.
  
  
  RESULTS
  Discriminant validity was confirmed for all instruments by finding statistically significant differences in summary scores and utilities between nearly all subgroups. Convergent validity between the summary scores/utilities of the IPSS and the GQoL instruments was weak (absolute correlation value range, 0.11-0.23) but differed considerably between dimensions of the instruments (absolute correlation value range, 0.01-0.24). Weak to moderate correlation between the GQoL instruments was seen (absolute correlation value range, 0.01-0.49).
  
  
  CONCLUSIONS
  Our findings suggest that the IPSS has comparable discriminant validity to the GQoL instruments and therefore useful for assessing subgroup differences related to urinary symptoms. The weak convergence between the IPSS and the GQoL instruments however suggests that, within economic evaluation, the IPSS should be viewed as a complement rather than a substitute to the GQoL instruments because it captures different quality of life constructs.
authors.affiliation: Flinders Health Economics Group, School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: Christine
authors.initials: C
authors.lastname: Mpundu-Kaambwa
authors.affiliation: Flinders Health Economics Group, School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: Billingsley
authors.initials: B
authors.lastname: Kaambwa
authors.affiliation: Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Appleton
authors.affiliation: Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Sean
authors.initials: S
authors.lastname: Martin
authors.affiliation: Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Gary
authors.initials: G
authors.lastname: Wittert
authors.affiliation: The Health Observatory, Discipline of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Adams
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D016002:Discriminant Analysis; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000191:economics / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Assessment of Quality of Life 4 Dimensions; International Prostate Symptom Score; Short-Form 6 Dimensions; lower urinary tract symptoms; quality of life