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Table 4 Linear mixed effects models to evaluate the effects of the M-DEPTH intervention, and change in depression, on measures of maternal functioning over 18 months of post-partum follow-up

From: Effects of M-DEPTH model of depression care on maternal depression, functioning, and HIV care adherence, and infant developmental over eighteen months post-partum: results from a cluster randomized controlled trial

 

Infant care

Self-care

Household functioning

Work functioning

Overall functioning

Post-partum adjustment

Effect of intervention

Joint significance tests

F(df); p

F(df); p

F(df); p

F(df); p

F(df); p

F(df); p

Time

101.7 (3,991); < 0.0001

78.3 (3,994); <0.0001

273.4 (3,994); <0.0001

6.7 (3,994); 0.0002

350.0 (3,994); <0.0001

8.0 (3,993); <0.0001

Time X intervention

14.6 (4,991); <0.0001

3.5 (4,994); 0.0075

4.8 (4,994); 0.0008

2.1 (4,994); 0.08

1.7 (4,994); 0.16

5.6 (4,993); 0.0002

Interaction effects

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Intervention X Month 2

0.22 (0.04); <0.0001

0.09 (0.04); 0.03

-0.22 (0.05); <0.0001

-0.01 (0.04); 0.88

-0.02 (0.03); 0.53

-0.03 (0.07); 0.64

Intervention X Month 6

0.17 (0.04); <0.0001

0.11 (0.04); 0.01

-0.05 (0.05); 0.33

0.03 (0.04); 0.45

0.05 (0.03); 0.06

-0.14 (0.07); 0.03

Intervention X Month 12

0.04 (0.04); 0.27

0.10 (0.04); 0.01

-0.03 (0.05); 0.51

0.02 (0.04); 0.69

0.03 (0.03); 0.30

-0.09 (0.07); 0.16

Intervention X Month 18

-0.02 (0.03); 0.53

0.11 (0.03); 0.001

-0.04 (0.04); 0.32

0.08 (0.03); 0.009

0.03 (0.02); 0.18

-0.23 (0.06); <0.0001

Effect of change in depression status

Joint significance test

F(df); p

F(df); p

F(df); p

F(df); p

F(df); p

F(df); p

Change in depression status

84.4 (2,665); <0.0001

63.9 (2,658); <0.0001

0.8 (2,658); 0.44

0.8 (2,658); 0.45

28.2 (2,658); <0.0001

6.9 (2,657); 0.001

Main effects

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Not depressed to depressed

0.01 (0.05); 0.81

0.04 (0.05); 0.48

-0.06 (0.07); 0.40

0.01 (0.05); 0.86

-0.003 (0.03); 0.93

-0.06 (0.07); 0.40

Depressed to not depressed

0.29 (0.03); <0.0001

0.28 (0.03); <0.0001

-0.04 (0.04); 0.24

0.04 (0.03); 0.21

0.12 (0.02); <0.0001

-0.04 (0.04); 0.24

Repeated not depressed

0.38 (0.03); <0.0001

0.26 (0.03); <0.0001

-0.10 (0.04); 0.03

-0.00 (0.03); 0.99

0.10 (0.02); <0.0001

-0.10 (0.04); 0.03

Time (linear)

0.09 (0.01); <0.0001

0.08 (0.01); <0.0001

0.23 (0.01); <0.0001

-0.02 (0.01); 0.008

0.12 (0.01); <0.0001

0.23 (0.01); <0.0001

Effect of change in depressive symptoms (PHQ-9 score)

Main effects

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Beta (SE); p

Time (linear)

0.08 (0.01); <0.0001

0.07 (0.01); <0.0001

0.24 (0.01); <0.0001

-0.03 (0.01); 0.003

0.12 (0.01); <0.0001

0.24 (0.01); <0.0001

Effect of change in PHQ-9 score

-0.03 (0.002); <0.0001

-0.03 (0.002); <0.0001

0.01 (0.003); 0.003

-0.01 (0.002); 0.02

-0.01 (0.001); <0.0001

0.01 (0.003); 0.003

Effect size

- 0.44

− 0.46

− 0.09

− 0.09

− 0.23

− 0.23

  1. SE = standard error; df = degrees of freedom; PHQ-9 = Patient Health Questionnaire (9-item version)
  2. All models included these baseline covariates: age, relationship status (in a committed relationship; yes/no), any secondary schooling (yes/no), newly diagnosed with HIV (yes/no), PHQ-9 score at eligibility screening, undetectable HIV viral load (yes/no)
  3. The model specification included time as a categorical variable with indicators for each follow-up assessment (month 2, month 6, month 12, month 18). The joint tests of overall effect of time and intervention are Type 3 tests of fixed effects. The coefficients of the main effects of time are not shown here. The key coefficients of interest are the interaction terms between Intervention and time, which are the (covariate-adjusted) difference between the Intervention (intervention = 1) group and the control group (Intervention = 0); a p-value < 0.05 indicates a statistically significant difference between the means of the two study arms. Further, note that to estimate the mean in the intervention group, one must add the main effect of time to the interaction between intervention and time. The effect size is a standardized regression coefficient to show magnitude that’s unitless and comparable across models [41].