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Table 2 Random effects meta-regression analysis, association of explanatory variables with control group weight change (kg)

From: Weight change in control group participants in behavioural weight loss interventions: a systematic review and meta-regression study

  

Uni-variable

Multi-variable

Trial and participant characteristics:

Study n

Weight change coefficient (95%CI)

p-value

Weight change coefficient (95%CI)

p-value

Method of ascertaining SE of weight change

       

  Reported (ref = 0)

23

      

  From SE/SD/exact p

49

−1.02

(−2.00, -0.03)

0.043

−0.82

(−1.85, 0.21)

0.119

Sample size

       

  <100 (ref = 0)

61

      

  ≥100

11

−0.01

(−0.85, 0.83)

0.976

0.68

(−0.32, 1.68)

0.181

Trial design

       

  Quasi-experimental (ref = 0)

6

      

  RCT

66

−1.11

(−2.17, -0.06)

0.038

−0.37

(−1.56, 0.81)

0.538

Recruitment strategy

       

  Media appeal for volunteers (ref = 0)

43

      

  Searches of existing registers

29

−0.03

(−0.71, 0.66)

0.937

−0.13

(−0.62, 0.88)

0.732

Intervention duration

       

  ≤6 months (ref = 0)

47

      

  >6 months

25

0.29

(−0.41, 1.00)

0.412

0.72

(−0.17, 1.61)

0.113

Total number of assessments

       

  2

52

      

  >2 (ref = 0)

20

−0.47

(−1.24, 0.30)

0.234

−0.27

(−1.06, 0.51)

0.492

Control group treatment

       

  No intervention control group (ref = 0)

26

      

  Wait list control group

13

0.26

(−0.65, 1.16)

0.579

0.85

(−0.10, 1.80)

0.079

  Usual care group

33

−0.84

(−1.55, -0.13)

0.021

−1.23

(−2.22, -0.23)

0.016

Age

       

  ≤50 years (ref = 0)

34

      

  >50 years

35

−0.01

(−0.71, 0.69)

0.971

−0.32

(−1.07, 0.43)

0.406

Gender

       

  Mixed gender or mostly male (ref = 0)

33

      

  Mostly female (>60 % female)

39

−0.22

(−0.90, 0.45)

0.517

0.14

(−0.56, 0.84)

0.695

Target population

       

  Chronic disease (ref = 0)

23

      

  Healthy or at risk of chronic disease

49

−0.38

(−1.09, 0.32)

0.286

−0.49

(−1.26, 0.29)

0.216

Baseline BMI category

       

  Healthy or overweight (≤ 30 kg/m2) (ref = 0)

26

      

  Obese (> 30 kg/m2)

43

−0.24

(−0.96, 0.48)

0.513

−0.24

(−0.95, 0.47)

0.501