Pain relief that matters to patients: systematic review of empirical studies assessing the minimum clinically important difference in acute pain

Table 5 Relationship between baseline pain and the minimum clinically important difference^a

Study	Subgroups by baseline pain, mm	Absolute MCID mm (95% CI)	Relative MCID % (95% CI)
Studies assessing MCID stratified by baseline pain
Stahmer [55]	≤50 > 50	NR NR	25 (SE: 10)^b 35 (SE: 6)^b
Voepel-Lewis [59]	<50 ≥ 50	0 (−30 to 20) 20 (13 to 25)	NR NR
Bird [31]	<34 34–66 > 66	11 (7 to 15) 17 (13 to 21) 30 (17 to 43)	NR NR NR
Cepeda [33]	Moderate (median: 60) Severe (median: 80)	13 (12 to 14) 18 (17 to 19)	20 (18 to 22) 20 (19 to 22)
Tsze [57]	<40 40–69 ≥ 70	NR NR NR	13 (0 to 29) 16 (10 to 23) 18 (11 to 29)
Tubach [58]	Low (mean: 55) Intermediate (mean: 70) High (mean: 85)	34 (29 to 38)^c 45^c 63 (54 to 68)^c	NR NR NR
Studies assessing correlation between MCID and baseline pain
Barton 2002 (reported in Jensen 2002 [43])	Correlation with baseline pain	0.48 (P < 0.001)	0.35 (P < 0.01)
Rasmussen 2002 (reported in Jensen 2002 [43])	Correlation with baseline pain	0.52 (P < 0.001)	0.34 (P < 0.01)
Farrar [36]	Correlation with baseline pain	Patients with higher baseline pain reported greater relief (e.g. 90 vs. 40 mm, P = 0.048)	No significant differences in degree of pain relief

^aTwo additional studies are not included, since they did not differentiate between pain relief and worsening when assessing the relationship between baseline pain and MCID (Kelly [46] and Lopez [21])
^bPatients answering ‘some’ or ‘partial’ relief
^cData is 75th percentile among patients answering ‘a great deal better’ (13) or ‘a good deal better’ (14) on a 15 category scale
MCID minimum clinically important difference, NR not reported, CI confidence interval

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