Comparative responsiveness of generic and specific quality-of-life instruments

Wiebe, Samuel; Guyatt, Gordon; Weaver, Bruce; Matijevic, Suzan; Sidwell, Casey

« Previous Next »Journal of Clinical Epidemiology
Volume 56, Issue 1 , Pages 52-60, January 2003

Comparative responsiveness of generic and specific quality-of-life instruments

Samuel Wiebe
- Corresponding author. Tel.: 519- 663-3984; fax: 519-663-3164.
- Department of Clinical Neurological Sciences and Epidemiology and Biostatistics, University of Western Ontario, University Campus, London Health Sciences Centre, 339 Windermere Road, London, Ontario, Canada N6A 5A5
Gordon Guyatt
- Department of Clinical Epidemiology and Biostatistics, McMaster University, 1200 Main Street West, L8N 3Z5, Hamilton, Ontario, Canada
- Department of Medicine, McMaster University, 1200 Main Street West, L8N 3Z5, Hamilton, Ontario, Canada
Bruce Weaver
- Department of Clinical Epidemiology and Biostatistics, McMaster University, 1200 Main Street West, L8N 3Z5, Hamilton, Ontario, Canada
Suzan Matijevic
- The London Health Sciences Centre, 339 Windermere Road, London, Ontario, N6A 5A5, Canada
Casey Sidwell
- The London Health Sciences Centre, 339 Windermere Road, London, Ontario, N6A 5A5, Canada

Received 31 May 2001; received in revised form 2 May 2002; accepted 20 August 2002.

Abstract

We assessed the relative responsiveness of generic and specific quality of life instruments in 43 randomized controlled trials that compared head-to-head 31 generic and 84 specific instruments. Using weighted effect size as the metric of responsiveness, we assessed the impact of instrument type, disease category, and magnitude of underlying therapeutic effect on responsiveness, and assessed the responsiveness of specific instruments relative to the corresponding domains of generic measures. In studies with a nonzero therapeutic effect, specific instruments (mean = 0.57) were significantly more responsive than generic instruments (mean = 0.39, P = .01), and than the corresponding domains of generic instruments (mean = 0.40, P = .03). Studies with low, medium, and high therapeutic effects showed a corresponding gradation in responsiveness differences between specific and generic instruments. We conclude that, overall, specific instruments are more responsive than generic tools, and that investigators may come to misleading conclusions about relative instrument responsiveness if they include studies in which the magnitude of the underlying therapeutic effect is zero.

Keywords: Responsiveness, Health-related quality of life, Generic and specific instruments, Effect size, Randomized controlled trials