Table 3 Structural equation modelling and mediation analysis to estimate the contribution of infant HIV exposure and ART score to %MTCT and the paediatric case rate

Coef (95%CI)

Standardized coef

p-value

 Direct effects

0.11 (-0.15, 0.37)

0.15

0.398

-0.11 (-0.15, 0.08)

-0.85

<0.001

3.64 (2.27, 5.02)

0.63

<0.001

Indirect (mediation) effect^b

-0.41 (-0.61, -0.21)

-0.54

<0.001

Total effects

-0.30 (-0.54, -0.05)

-0.39

0.018

-0.11 (-0.15, -0.08)

-0.85

<0.001

3.65 (2.27, 5.02)

0.63

<0.001

 Model

independent variable

outcome

Coef (95% CI)

Standardized coef. (Adjusted R²)

p-value

 Simple linear

HEI

% MTCT

-0.27 (-0.58, 0.04)

-0.35 (0.08)*

0.089

ART_score

% MTCT

-0.10 (-0.14, -0.06)

-0.74 (0.53)*

<0.001

HEI

ART_score

3.39 (1.41, 5.36)

0.60 (0.34)^*

0.002

 Multiple regression

HEI

ART_score

% MTCT

0.11 (-0.17, 0.40)

0.15.^a

0.418

%MTCT

-0.11 (-0.16, -0.06)

-0.85 (0.53^a) 

<0.001

Mediated effects^b

HEI

% MTCT

-0.38 (-0.64, -0.21)

<0.001

Effect

Coef (95%CI)

Standardized coef

p-value

 Direct effects

82.2 (66.1,98.3)

1.03

<0.001

-2.9 (-5.7, -0.01)

-0.21

0.05

3.7 (2.0, 5.5)

0.64

<0.001

Indirect (mediation) effect^b

-10.6 (-22.4, 1.2)

-0.13

0.077

Total effects

71.6 (57.9, 85.3)

0.90

<0.001

-2.9 (-5.7, -0.01)

-0.21

0.05

3.73 (2.0, 5.5)

0.64

<0.001

 Model

predictor

outcome

Coef (95% CI)

Standardized coef. (Adjusted R²)

p-value

 Simple linear

HEI

Case_rate

72.8 (57.5, 88.2)

0.90 (0.81)^*

<0.001

ART_score

Case_rate

6.1 (0.92, 11.4)

0.45 (0.17)^*

0.023

HEI

ART_score

3.4 (1.4, 5.4)

0.60 (0.34)^*

0.002

 Multiple regression

HEI

Case_rate

82.8 (64.6, 101.1)

1.03 (0.83^a)

<0.001

ART_score

Case rate

-3.0 (-6.2, 0.31)

-0.20

0.074

Mediated effects^b

HEI

Case_rate

-10.0 (-21.8, 1.8)

>0.05