Absolute MCID was strongly associated with baseline pain , explaining approximately two-thirds of the variation , and to a lesser degree with the operational definition of minimum pain relief and clinical condition .
MCID  for chronic pain relief vary considerably .
Baseline pain is strongly associated with absolute , but not relative , measures .
To a much lesser degree , MCID is also influenced by the operational definition of relevant pain relief and possibly by clinical condition .
BACKGROUND The minimum clinical ly important difference ( MCID ) is used to interpret the relevance of treatment effects , e.g. , when developing clinical guidelines , evaluating trial results or planning sample sizes .
There is currently no agreement on an appropriate MCID in chronic pain and little is known about which context ual factors cause variation .
METHODS This is a systematic review .
The clinical importance of changes in the 0 to 10 numeric rating scale for worst, least, and average pain intensity: analyses of data from clinical trials of duloxetine in pain disorders.
UNLABELLED Data on 1,700 patients pooled from 5 r and omized , placebo-controlled duloxetine studies ( 3 in diabetic peripheral neuropathic pain and 2 in fibromyalgia ) were analyzed to determine clinical ly important differences ( CIDs ) in the 0 to 10 Numeric Rating Scale-Pain Intensity ( NRS-PI ) for patient-reported " worst " and " least " pain intensity while validating the previously published level for " average " pain . The correspondence between the baseline-to-endpoint raw and percentage change in the NRS-PI for the worst , least , and average pain were compared to patients ' perceived improvements at endpoint as measured by the 7-point Patient Global Impression of Improvement ( PGI-I ) scales . Stratification by baseline pain separated the raw but not the percent change scores . The PGI-I category of " much better " or above was our a priori definition of a CID . Cutoff points for the NRS-PI change scores were determined using a receiver operator curve analysis . A consistent relationship between the worst and average NRS-PI percent change and the PGI-I was demonstrated regardless of the study , pain type , age , sex , or treatment group with a reduction of approximately 34 % . The least pain item CID was slightly higher at 41 % . Raw change CID cutoff points were approximately -2 , -2.5 and -3 for least , average , and worst pain respectively . PERSPECTIVE We determined an anchor-based value for the change in the worst , least , and average pain intensity items of the Brief Pain Inventory that best represents a clinical ly important difference . Our findings support a st and ard definition of a clinical ly important difference in clinical trials of chronic-pain therapies
Absolute MCID was strongly associated with baseline pain , explaining approximately two-thirds of the variation , and to a lesser degree with the operational definition of minimum pain relief and clinical condition .
MCID  for chronic pain relief vary considerably .
Baseline pain is strongly associated with absolute , but not relative , measures .
To a much lesser degree , MCID is also influenced by the operational definition of relevant pain relief and possibly by clinical condition .
BACKGROUND The minimum clinical ly important difference ( MCID ) is used to interpret the relevance of treatment effects , e.g. , when developing clinical guidelines , evaluating trial results or planning sample sizes .
There is currently no agreement on an appropriate MCID in chronic pain and little is known about which context ual factors cause variation .
METHODS This is a systematic review .