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 .
Neck Disability Index, short form-36 physical component summary, and pain scales for neck and arm pain: the minimum clinically important difference and substantial clinical benefit after cervical spine fusion.
BACKGROUND CONTEXT The Neck Disability Index ( NDI ) , the short form-36 ( SF-36 ) physical component summary ( PCS ) , and pain scales for arm and neck pain are increasingly used to evaluate treatment effectiveness after cervical spine surgery . The minimum clinical ly important difference ( MCID ) is a threshold of improvement that is clinical ly relevant to the patient . However , the true goal is to provide the patient with a substantial clinical benefit ( SCB ) . PURPOSE This study determines the MCID and SCB using common anchor-based methods for NDI , PCS , and pain scales for arm and neck pain in patients undergoing cervical spine fusion for degenerative disorders . STUDY DESIGN / SETTING The study setting is a longitudinal cohort in a multisurgeon spine specialty clinic . PATIENT SAMPLE The sample comprises 505 patients who underwent a cervical fusion for degenerative spine conditions and who have prospect ively collected outcome scores with a minimum 1-year follow-up . OUTCOME MEASURES The outcome measures of the study were NDI , SF-36 , and numeric rating scales for arm and neck pain . METHODS The MCID and SCB values for NDI , PCS , and pain scales for arm and neck pain were determined using receiver operating characteristic ( ROC ) curve analysis with the Health Transition Item of the SF-36 as an anchor . The Health Transition Item asks a patient " Compared to one year ago , how would you rate your health in general now ? " with answers ranging from " Much Better , " " Somewhat Better , " " About the Same , " " Somewhat Worse , " to " Much Worse . " An ROC curve was constructed for each measure . The ROC curve-derived MCID was the change score with equal sensitivity and specificity to distinguish the " Somewhat Better " from the " About the Same " patients . The ROC curve-derived SCB was the change score with equal sensitivity and specificity to distinguish the " Much Better " from the " Somewhat Better " patients . Distribution-based methods including the st and ard error of the mean and the minimum detectable change were also used to calculate MCID . RESULTS The calculated MCID is 7.5 for the NDI , 4.1 for SF-36 PCS , and 2.5 for arm and neck pain . The calculated SCB is 9.5 for the NDI , 6.5 for SF-36 PCS , and 3.5 for arm and neck pain . CONCLUSIONS Patients with an eight-point decrease in NDI , a 4.1-point increase in PCS , and a three-point decrease in arm or neck pain can detect a minimally clinical ly important change . Patients with a 10-point decrease in NDI , a 6.5-point increase in PCS , and a four-point decrease in arm or neck pain can detect an SCB after cervical spine fusion
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 .