The change on the Numeric Rating Scale (NRS) is constructed on subjective pain experiences, hampering the establishment of the clinically important improvement. Hence, an anchor based method; the Patients Global Impression of Change (PGIC) is added to determine. A 2-point change on the NRS is equivalent to a moderate clinically important improvement in randomized controlled trials (RCT’s), when treating chronic pain patients with medication. We contemplated whether these findings would be assessed in the DATAPAIN cohort and non-drug interventional RCT’s of our pain medicine department.

The NRS change was quantified by subtracting the NRS of baseline from the NRS at 6 months follow-up. Categorization of success/nonsuccess was applied on the PGIC and their average NRS raw changes were calculated. The Spearman correlation coefficient quantified the overall relationship, while the discriminative ability was explored through the receiver operating characteristic curve. Data was stratified on design, sex and pain intensity at baseline. Besides, the cohort evaluated treatment status at follow-up.

The records of 1661 patients were examined. Overall, the observed NRS change needed for moderate clinically important improvement was larger than the average 2 points. Yet, the changes of the cohort were smaller compared to the RCT’s. Moreover, it modified with pain intensity at baseline and treatment statuses indicated differences in mean clinical importance of -4.15(2.70) when finalized at 6 months and -2.16(2.48) when treatment was ongoing.

The moderate clinically important improvement varied substantially. Representing heterogeneity in pain relief and its relation to treatment success in chronic pain patients.