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 .
Outcome measures in chronic low back pain
The purpose of this prospect i ve , single site cohort quasi-experimental study was to determine the responsiveness of the numerical rating scale ( NRS ) , Rol and –Morris disability question naire ( RMDQ ) , Oswestry disability index ( ODI ) , pain self-efficacy question naire ( PSEQ ) and the patient-specific functional scale ( PSFS ) in order to determine which would best measure clinical ly meaningful change in a chronic low back pain ( LBP ) population . Several patient-based outcome instruments are currently used to measure treatment effect in the chronic LBP population . However , there is a lack of consensus on what constitutes a “ successful ” outcome , how an important improvement/deterioration has been defined and which outcome measure(s ) best captures the effectiveness of therapeutic interventions for the chronic LBP population . Sixty-three consecutive patients with chronic LBP referred to a back exercise and education class participated in this study ; 48 of the 63 patients had complete data . Five question naires were administered initially and after the 5-week back class intervention . Also at 5 weeks , patients completed a global impression of change as a reflection of meaningful change in patient status . Score changes in the five different question naires were subjected to both distribution- and anchor-based methods : st and ard error of measurement ( SEM ) and receiver operating characteristic ( ROC ) curves to define clinical improvement . From these methods , the minimal clinical ly important difference ( MCID ) defined as the smallest difference that patients and clinicians perceive to be worthwhile is presented for each instrument . Based on the SEM , a point score change of 2.4 in the NRS , 5 in the RMDQ , 17 in the ODI , 11 on the PSEQ , and 1.4 on the PSFS corresponded to the MCID . Based on ROC curve analysis , a point score change of 4 points for both the NRS and RMDQ , 8 points for the ODI , 9 points for the PSEQ and 2 points for the PSFS corresponded to the MCID . The ROC analysis demonstrated that both the PSEQ and PSFS are responsive to clinical ly important change over time . The NRS was found to be least responsive . The exact value of the MCID is not a fixed value and is dependent on the assessment method used to calculate the score change . Based on ROC curve analysis the PSFS and PSEQ were more responsive than the other scales in measuring change in patients with chronic LBP following participation in a back class programme . However , due to the small sample size , the lack of observed worsening of symptoms over time , the single centre and intervention studied these results which need to be interpreted with caution
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 .