Interpreting the clinical importance of treatment outcomes in chronic pain clinical trials: IMMPACT recommendations.
A consensus meeting was convened by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) to provide recommendations for interpreting clinical importance of treatment outcomes in clinical trials of the efficacy and effectiveness of chronic pain treatments. A group of 40 participants from universities, governmental agencies, a patient self-help organization, and the pharmaceutical industry considered methodologic issues and research results relevant to determining the clinical importance of changes in the specific outcome measures previously recommended by IMMPACT for 4 core chronic pain outcome domains: (1) Pain intensity, assessed by a 0 to 10 numerical rating scale; (2) physical functioning, assessed by the Multidimensional Pain Inventory and Brief Pain Inventory interference scales; (3) emotional functioning, assessed by the Beck Depression Inventory and Profile of Mood States; and (4) participant ratings of overall improvement, assessed by the Patient Global Impression of Change scale. It is recommended that 2 or more different methods be used to evaluate the clinical importance of improvement or worsening for chronic pain clinical trial outcome measures. Provisional benchmarks for identifying clinically important changes in specific outcome measures that can be used for outcome studies of treatments for chronic pain are proposed.


CONCLUSIONS
Systematically collecting and reporting the recommended information needed to evaluate the clinical importance of treatment outcomes of chronic pain clinical trials will allow additional validation of proposed benchmarks and provide more meaningful comparisons of chronic pain treatments.
Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA. robert_dworkin@urmc.rochester.edu
Robert H
RH
Dworkin
Dennis C
DC
Turk
Kathleen W
KW
Wyrwich
Dorcas
D
Beaton
Charles S
CS
Cleeland
John T
JT
Farrar
Jennifer A
JA
Haythornthwaite
Mark P
MP
Jensen
Robert D
RD
Kerns
Deborah N
DN
Ader
Nancy
N
Brandenburg
Laurie B
LB
Burke
David
D
Cella
Julie
J
Chandler
Penny
P
Cowan
Rozalina
R
Dimitrova
Raymond
R
Dionne
Sharon
S
Hertz
Alejandro R
AR
Jadad
Nathaniel P
NP
Katz
Henrik
H
Kehlet
Lynn D
LD
Kramer
Donald C
DC
Manning
Cynthia
C
McCormick
Michael P
MP
McDermott
Henry J
HJ
McQuay
Sanjay
S
Patel
Linda
L
Porter
Steve
S
Quessy
Bob A
BA
Rappaport
Christine
C
Rauschkolb
Dennis A
DA
Revicki
Margaret
M
Rothman
Kenneth E
KE
Schmader
Brett R
BR
Stacey
Joseph W
JW
Stauffer
Thorsten
T
von Stein
Richard E
RE
White
James
J
Witter
Stojan
S
Zavisic
D002986:Clinical Trials as Topic / Q000379:methods*; D006801:Humans; D059408:Pain Management; D010147:Pain Measurement / Q000379:methods*; D012107:Research Design; D016896:Treatment Outcome