RT Journal Article
SR Electronic
T1 Responsiveness of Single versus Composite Measures of Pain in Knee Osteoarthritis
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 1308
OP 1315
DO 10.3899/jrheum.170928
VO 45
IS 9
A1 Matthew J. Parkes
A1 Michael J. Callaghan
A1 Leslie Tive
A1 Mark Lunt
A1 David T. Felson
YR 2018
UL http://www.jrheum.org/content/45/9/1308.abstract
AB Objective. In rheumatoid arthritis, composite outcomes constructed from a combination of outcome measures are widely used to enhance responsiveness (sensitivity to change) and comprehensively summarize response. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain is the primary outcome measure in many osteoarthritis (OA) trials. Information from other outcomes, such as rescue medication use and other WOMAC subscales, could be added to create composite outcomes, but the sensitivity of such a composite has not been tested.Methods. We used data from a completed trial of tanezumab for knee OA (NCT00733902). The WOMAC questionnaire and rescue medication use were measured at several timepoints, up to 16 weeks. Pain and rescue medication outcomes were standardized and combined into 3 composite outcomes through principal components analysis to produce 1 score (composite outcome) and their responsiveness was compared to WOMAC pain, the standard. We pooled all treatment doses of tanezumab into 1 treatment group, for simplicity, and compared this to the control group (placebo).Results. The composite outcomes showed modestly, but not statistically significantly greater responsiveness when compared to WOMAC pain alone. Adding information on rescue medication to the composite improved responsiveness. While improvements in sensitivity were modest, the required sample sizes for trials using composites was 20–40% less than trials using WOMAC pain alone.Conclusion. Combining information from related but distinct outcomes considered relevant to a particular treatment improved responsiveness, could reduce sample size requirements in OA trials, and might offer a way to better detect treatment efficacy in OA trials.