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 .
Criteria for Success after Surgery for Cervical Radiculopathy; Estimates for a Substantial Amount of Improvement in Core Outcome Measures.
IMPORTANCE Defining clinical ly meaningful success criteria from patient-reported outcome measures ( PROMs ) is crucial for clinical audits , research and decision-making . PURPOSE We aim ed to define criteria for a successful outcome 3 and 12 months after surgery for cervical degenerative radiculopathy ( CDR ) on recommended PROMs . STUDY DESIGN Prospect i ve cohort study with 12 months follow-up . PATIENT SAMPLE Patients operated at one or two levels for cervical radiculopathy included in the Norwegian Registry for Spine Surgery ( NORspine ) from 2011 to 2016 . OUTCOME MEASURES Neck Disability Index ( NDI ) , Numeric Rating Scale for neck pain ( NRS-NP ) and arm pain ( NRS-AP ) , health-related quality -of-life EuroQol 3L ( EQ-5D ) , general health status ( EQ-VAS ) . METHODS We included 2868 consecutive CDR patients operated for cervical radiculopathy in one or two levels and included in the Norwegian Registry for Spine Surgery ( NORspine ) . External criterion to determine accuracy and optimal cut-off values for success in the PROMs was the Global Perceived Effect Scale ( GPE ) . Success was defined as " much better " or " completely recovered " . Cut-off values were assessed by analyzing the area under the receiver operating curves ( ROC ) for follow-up scores , mean change scores , and percentage change scores . RESULTS All PROMs showed high accuracy in defining success and non-success and only minor differences were found between 3- and 12-month scores . At 12 months , the area under the ROC for follow-up scores were 0.86 - 0.91 , change scores were 0.74 - 0.87 , and percentage change scores were 0.74 - 0.91 . Percentage scores of NDI and NRS-AP showed the best accuracy . The optimal cut-off values for each PROM showed considerable overlap across those operated due to disc herniation and spondylotic foraminal stenosis . CONCLUSIONS All PROMs , especially NDI and NRS-AP , showed good to excellent discriminative ability in distinguishing between a successful and non-successful outcome after surgery due to cervical radiculopathy . Percentage change scores are recommended for use in research and clinical practice
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 .