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