Table 2 Example of calculations of MCID and CID in pain score in OA patients
Reference (treatment) | Method | Categories in anchor | Definition of MCID or CID for improvement | MCID or CID |
|---|---|---|---|---|
Pain on VAS (0–100 mm scale) | ||||
Tubach 2005 (NSAIDs) [10] | Anchor—PGA | None, poor, fair, good, excellent | 75th percentile of the change in score among patients whose evaluation of response to treatment (on PGA) was “good” (MCID) | −19.9 mm (knee) − 15.3 mm (hip) |
Pain on NRS (0–10 pt) | ||||
Farrar 2001 [11] | Anchor―PGIC | Very much improved, much improved, minimally improved, no change, minimally worse, much worse, very much worse | Decrease in pain score for patients “much improved” (CID) | 2 pt |
Decrease in pain score for patients “very much improved” (CID) | ≥4 pt | |||
ROC—PGIC | Very much improved, much improved, minimally improved, no change, minimally worse, much worse, very much worse | Decrease in pain score for patients “much improved” (CID) | ≥1.7 pt | |
Pain on WOMAC (on 0–100 pt scale, unless otherwise noted) | ||||
Ehrich 2000 (NSAIDs) [12] | Anchor—PGA | None, poor, fair, good, excellent | Difference btw “none” and “poor” response on PGA (MCID) | 9.7 mm |
Angst 2001 (inpatient rehabilitation) [13] | Anchor—transition question | Much worse, slightly worse, equal, slightly better, much better | Difference btw “equal” and “slightly better” groups (MCID) | 0.75 pta |
Escobar 2007 (TKR) [14] | Anchor—transition question | A great deal better, somewhat better, equal, somewhat worse, a great deal worse | Difference btw baseline score and scores for patients declaring changes “somewhat better” (MCID) | 23 pt |
Quintana 2012 (THR) [15]a | Anchor—transition question | Seven items from “a great deal better” to “a great deal worse” | Mean change score for patients whose response was “a little better” (MCID) | 15, 23, 36 ptb |
Anchor—PASS question | Totally satisfied, slightly satisfied, not satisfied, not at all satisfied | Mean change in score for the 75th percentile of patients in the probability curve reporting being totally satisfied or slightly satisfied (MCID) | 20, 25, 25 ptb | |
ROC—PASS question | Totally satisfied, slightly satisfied, not satisfied, not at all satisfied | Patients reporting being totally satisfied or slightly satisfied—optimal point on curve (MCID) | 19, 25, 25 ptb | |
Escobar 2013 (TKR) [16] | Anchor—transition question | A great deal better, somewhat better, equal, somewhat worse, a great deal worse | Mean change in patients “somewhat better” (MCID) | 30 pt |
ROC—transition question | A great deal better, somewhat better, equal, somewhat worse, a great deal worse | Mean change in patients “somewhat better” (MCID) | 20–24 ptc | |
Anchor—question about satisfaction | Very satisfied, somewhat satisfied, somewhat dissatisfied and very dissatisfied | Patient “somewhat satisfied” (MCID) | 27 pt | |
SF-36 bodily pain (0–100 pt scale) | ||||
Angst 2001 (inpatient rehabilitation) [13] | Anchor—“transition” questionnaire | Much worse, slightly worse, equal, slightly better, much better | Improvement MCID = Difference btw “equal” and “slightly better” (MCID) | 7.8 pt for improvement |
Escobar 2007 (TKR) [14] | Anchor—“transition” question at 6 months or 2 years | A great deal better, somewhat better, equal, somewhat worse, a great deal worse | Difference btw baseline score and scores for patients declaring changes “somewhat better” (MCID) | 17 pt |