Table 2 Meta-regression analysis and tendency test of placebo response with associated factors in patients with diabetes mellitus

β

95% CI

P value

β

95% CI

P value

  Age (year)

− 0.01

− 0.02, − 0.01

< 0.01

− 0.04

− 0.09, 0.01

0.09

  Male percentage (%)

0.04 × 10⁻²

− 0.09 × 10⁻², 0.99 × 10⁻²

0.93

− 0.03

− 0.06, 0.49 × 10⁻²

0.09

  Duration of DM (year)

− 0.02

− 0.03, − 0.21 × 10⁻²

0.03

− 0.01

− 0.07, 0.05

0.71

  Study duration (week)

0.18 × 10⁻²

− 0.14 × 10⁻², 0.50

0.27

− 0.26 × 10⁻²

− 0.01, 0.83 × 10⁻²

0.63

  Baseline HbA1c (%)

0.04

− 0.10, 0.18

0.57

− 0.18

− 0.68, 0.31

0.45

  Adjusted HbA1c (%)*

− 0.09

− 0.19, 0.01

0.07

− 0.26

− 0.67, 0.15

0.20

  Baseline BMI (kg/m²)

− 0.01

− 0.05, 0.03

0.57

0.08

− 0.07, 0.23

0.30

  Adjusted BMI (kg/m²)^†

− 0.03

− 0.09, 0.02

0.19

− 0.01

− 0.22, 0.20

0.92

Linear term

F value

P value

Linear term

F value

P value

  Publication year

0.03

0.28

0.60

1.89

3.00

0.09

β

95% CI

P value

β

95% CI

P value

  Age (year)

0.02

0.01, 0.03

0.01

0.02

− 0.01, 0.05

0.22

  Male percentage (%)

0.01

0.22 × 10⁻², 0.01

< 0.01

0.21 × 10⁻²

− 0.01, 0.01

0.71

  Duration of DM (year)

− 0.01

− 0.02, 0.01

0.30

0.06

0.02, 0.10

< 0.01

  Study duration (week)

0.10 × 10⁻³

− 0.23 × 10⁻², 0.25 × 10⁻²

0.94

− 0.05 × 10⁻²

− 0.01, 0.01

0.86

  Baseline HbA1c (%)

− 0.09

− 0.16, − 0.01

0.02

0.13

− 0.10, 0.35

0.28

  Adjusted HbA1c (%)*

− 0.04

− 0.16, 0.08

0.52

0.10

− 0.23, 0.44

0.54

  Baseline BMI (kg/m²)

− 0.02

− 0.04, − 0.26 × 10⁻²

0.02

− 0.03

− 0.07, 0.01

0.14

  Adjusted BMI (kg/m²)^†

− 0.01

− 0.03, 0.01

0.41

− 0.01

− 0.06, 0.03

0.51

Linear term

F value

P value

Linear term

F value

P value

  Publication year

0.85

3.21

0.07

6.85

3.31

0.07