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Table 4 Subgroup analyses of absolute minimum clinically important differences (MCIDs) for pain relief

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

Subgroup

Analysis of medians

Analysis of pooled average

Range, mm

Number of studiesa (patientsb)

MCID Median, mm (IQR)

Number of studies (patientsb)

MCID pooled average, mm (95% CI), I2 c

All studies

8–40

29 (6517)

17 (14–23)

23 (6024)

17 (15–19), 93%

Clinical conditions

 Post-operation paind

9–29

7 (731)

18 (10–25)

3 (361)

11 (8–14), 42%

 Trauma

16–20

2 (125)

18 (16–20)

2 (125)

18 (15–22), 11%

 Abdominal pain

18–25

2 (407)

21 (18–25)

2 (407)

21 (15–28), 91%

 Mixed patients at ED

8–24

7 (2418)

15 (11–21)

6 (2345)

16 (12–20), 90%

 Othere

10–40

5 (1980)

27 (23–34)

4 (1930)

22 (15–29), 92%

 Unspecified

13–21

6 (856)

16 (14–16)

6 (856)

16 (14–18), 72%

Definition of MCID

 One category improvement

8–34

24 (4504)

16 (13–21)

22 (4281)

16 (14–18), 91%

 Several categories improvement

23–29

3 (220)

25 (23–29)

NA

NA

 Meaningful change

27–40

2 (1793)

34 (27–40)

1 (1743)

27 (25–29), NA

Directionality of transition scale

 One-sided

9–40

5 (538)

18 (13–21)

3 (383)

15 (8–21), 93%

 Two-sided

8–25

19 (3962)

16 (13–20)

18 (3844)

16 (14–19), 91%

Pain scale

 Visual Analogue Scale

8–40

17 (3232)

17 (13–25)

15 (3109)

16 (13–19), 91%

 Numeric Rating Scale

10–23

7 (1268)

15 (14–21)

6 (1118)

16 (14–19), 91%

Measurements per patient

 Single

18–40

4 (461)

25 (23–29)

4 (2058)

22 (19–25), 0%

 Multiple

  With adjustment

10–18

9 (1104)

15 (13–16)

8 (1031)

15 (13–16), 34%

  Without Adjustment/unclear

8–25

11 (2935)

16 (10–21)

11 (2935)

16 (13–20), 95%

Risk of attrition bias

 Low

8–40

8 (1249)

19 (15–25)

8 (1249)

16 (14–18), 81%

 High or unclear

9–25

16 (3251)

16 (12–19)

13 (2978)

16 (13–19), 93%

Risk of non-representative sampling

 Low

8–25

6 (1187)

16 (10–21)

6 (1187)

16 (11–21), 96%

 High or unclear

9–40

18 (3313)

18 (14–24)

15 (3040)

16 (14–18), 87%

  1. IQR inter-quartile range, ED Emergency department, NA not applicable
  2. aThe median is based on studies included in the pooled average as well as studies with unavailable standard errors
  3. bTotal number of patients in studies
  4. cI2 is the percentage of the variability in results that is due to heterogeneity rather than sampling error (chance); I2 of 0% to 40% might not be important, 30% to 60% may represent moderate heterogeneity, 50% to 90% may represent substantial heterogeneity, and 75% to 100% represents considerable heterogeneity
  5. dIncludes knee surgery, laparotomy, third molar extraction and mixed surgery (e.g. spinal fusion and splenectomy)
  6. eIncludes headache, low back pain, sickle cell crisis, rheumatic condition, and pain flare after external beam radiotherapy for bone metastases
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BMC Medicine

ISSN: 1741-7015

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