Table 2.
Equivalence test of WOMAC scores, CRP, and TNF-α at the end of the study
| Parameter | Group (n) | Week 6 | Median | Percentile | Mean difference ± SE | Confidence level of mean difference | Equivalence test | Effect sized | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean ± SE | 25th | 75th | 90% LCI | 90% UCI | Margin of equivalenced | p value | |||||
| Total WOMACb | Turmeric extract (n = 73) | 43.01 ± 2.62 | 40 | 26 | 63 | 5.08 ± 3.39 | − 0.54 | 10.71 | LL = −10.8 | 0 | 0.526 |
| Paracetamol (n = 71) | 37.93 ± 2.16 | 40 | 21 | 51 | UL = + 10.8 | 0.0474$ | |||||
| Paina,b | Turmeric extract (n = 73) | 8.78 ± 0.57 | 8 | 5 | 13 | 0.87 ± 0.75 | − 0.38 | 2.11 | LL = −2.2 | 0.00004 | 0.486 |
| Paracetamol (n = 71) | 7.92 ± 0.49 | 8 | 5 | 10 | UL = + 2.2 | 0.0389$ | |||||
| Stiffnessb | Turmeric extract (n = 73) | 3.01 ± 0.24 | 3 | 2 | 5 | − 0.59 ± 0.32 | − 1.12 | − 0.06 | LL = − 1.13 | 0.0481$ | 0.580 |
| Paracetamol (n = 71) | 3.61 ± 0.21 | 4 | 2 | 5 | UL = + 1.13 | 0 | |||||
| Functionb | Turmeric extract (n = 73) | 31.22 ± 1.90 | 30 | 17.5 | 45 | 4.81 ± 2.51 | 0.65 | 8.97 | LL = − 9.00 | 0 | 0.589 |
| Paracetamol (n = 71) | 26.41 ± 1.64 | 27 | 13 | 40 | UL = + 9.00 | 0.049$ | |||||
| CRPc | Turmeric extract (n = 72) | 14.73 ± 8.12 | 6 | 3 | 6 | LL = − 3.00 | 0.2589$ | 0.531 | |||
| Paracetamol (n = 68) | 18.38 ± 2.95 | 6 | 4.5 | 23.5 | UL = + 3.00 | 0 | |||||
| TNF-αc | Turmeric extract (n = 69) | 17.27 ± 4.08 | 6 | 0 | 12.65 | LL = − 6.00 | 0.0529$ | 0.580 | |||
| Paracetamol (n = 68) | 48.65 ± 17.17 | 10 | 1 | 28.5 | UL = + 6.00 | 0 | |||||
Margin of equivalence or non-inferiority margin = 0.5 of standard deviation. Effect size = margin of equivalence/standard deviation
LCI lower confidence interval of mean difference, UCI upper confidence interval of mean difference, LL lower limit of margin of equivalence, UL upper limit of margin of equivalence, SE standard error
aWOMAC pain scale is the primary outcome measure
bAspin–Welch unequal–variance T test for equivalence using two one-sided test (TOST)
cMann–Whitney U or Wilcoxon rank-sum location difference test for equivalence using two one-sided test (TOST)
dSee Additional file 3 for the derivation of margin of equivalence and effect size
$Higher p value is considered