Effect of prepare Intervention on sexual initiation and condom use among adolescents in Dar es Salaam: Preliminary analysis

AIMDar PREPARE Intervention aimed at examining the effect of the Intervention on;1. Delaying sexual debut(Incidence of sexual debut/ action planning to delay sex)

2. Practice of safer sexual behavior (Use of condom during last sex/Action plan to use condom)

School selection and allocation

38 schools randomly selected t represent urban and semi-urban Dar es salaamMatched by size and locationAllocated to the two arms (19 Intervention and 19 control schools )

Study Design

Control

Intervention

F1

F1

F2

F2

Intervention Booster

6 months 6 months

12 months

AnalysisCompare baseline socio-demographic and outcome scales by intervention statusExamine and test best correlation structure for repeated measures ( use QIC)Examine change in mean scores overtime using extended generalized estimating equation modeling (xtgee)for repeated measures (Use QIC)

Use of GEE (xtgee)Repeated measures are positively correlatedCorrelation decrease by measurement occasionGEE- form of Generalized Linear Mixed Model

Excellent for balanced designChange in link function accommodate Count (Poisson) or Binary (binomial) outcomeHandle more then two measurement occasionsControl for correlation

Schematic diagram of follow up rate

Baseline

5091

Months 6 (F1)

4783

Months 12 (F2)

4370

308 lost (6.0%)

413 lost (8.6%)

Baseline comparisonA total 5091 participants in baselineParticipants from control schools were significantly older than those from intervention school (12.39 versus 12.43; p=0.020)More from standard 6 (64.1% versus 61.8%; p=0.025)All other variables comparable (except HAVES, communication with friends and parents)

Variable Intervention

Control

Mean difference

P-value

Action plan condom use 2.598 2.578 0.0198 0.4743

Action plan delayed sex 2.809 2.793 0.1529 0.6163

Self-efficacy Communicate with peer

2.266 2.225 0.0407 0.0678

Peer communication 1.646 1.606 0.03944 0.0946

Communication with friends 1.384 1.338 0.0465 0.0007

Communication with parents

1.338 1.305 0.0335 0.0328

Self-efficacy to delay sex 2.591 2.596 0.0046 0.8614

Self-efficacy to use Condom 2.439 2.479 0.0396 0.0930

Social norms condom use 3.352 3.407 0.0549 0.0518

Social norm delay sex 3.516 3.487 0.0297 0.2780

Attitude delay sex (negative)

2.321 2.297 0.0239 0.3343

Attitude delay sex (positive) 3.433 3.433 0.0002 0.9936

Puberty knowledge 1.504 1.503 0.0005 0.9445

Myth about condom 2.231 2.244 0.0127 0.4939

Haves 3.771 3.992 -0.2208 0.0003

Baseline mean scale comparison between Intervention and control schools

Sexual activity and initiation

Significantly large proportion of intervention group participants were sexually active

(10.7% Intervention vs 8.9% control, p=0.026)

Incidence of sexual debut among female adolescent by intervention status

Female

Month 6

Month 12

InterventionN=1052 at risk

ControlN=1113 at risk

60 new initiationIncidence 11/100 PYAR

52 new initiationIncidence 9.0/100PYAR

75 new initiationIncidence 7/100PYAR

114 new initiationIncidence 9.7/100PYAR

RR =1.6, p=0.024

*Assumption: Debut occurred mid follow time

Incidence of sexual debut among male adolescent by intervention status

Male

Month 6

Month 12

InterventionN=1158 at risk

ControlN=1213 at risk

65 new initiationIncidence 10.9/100 PYAR

78 new initiationIncidence 12.4/100PYAR

87 new initiationIncidence 7.2/100PYAR

126 new initiationIncidence 10.0/100PYAR

RR =1.9, p<0.001

*Assumption: Debut occurred mid follow time

Change over time in mean scales for action plan to delay

sex

Month 0 Month 6 Month 12

2.788

2.741

2.836

2.767

2.819

2.893

Change overtime in mean scale for action planning to delay

sex among Female adolescents

Control Intervention Month 0 Month 6 Month 12

2.748

2.813

2.858

2.8212.848

2.939

Change overtime in mean scale for action planning to delay sex among Male ado-

lescents

Control Intervention

Change over time in mean scales for action plan to use condom

Month 0 Month 6 Month 12

2.445

2.624 2.616

2.432

2.6172.658

Change in mean scale overtime for action

planning to use condom among Female adoles-

cents

Control Intervention

Month 0 Month 6 Month 12

2.655

2.687

2.719

2.661

2.698

2.728

Change in mean scale overtime for action plan-

ning to use condom among Male adolescents

Control Intervention

Correlation and covariate structure pwcorr sex0 sex1 sex3 | sex0 sex1 sex3 sex0 | 1.0000 sex1 | 0.7000 1.0000 sex3 | 0.5791 0.8272 1.0000

corr sex0 sex1 sex3, cov | sex0 sex1 sex3 -------------+--------------------------- sex0 | .088426 sex1 | .080242 .148585 sex3 | .074042 .137103 .184882

Intervention effect on the mean score : Female  INTERVENTION   CONTROLVariable Occasion Coefficient P-value Coefficient P-value

Action to delay sex baseline ref ref   ref ref   Month 6 0.0469 0.256 0.0526 0.237  Month 12 0.1055 0.033 0.0686 0.144  Group 0.1345 0.015           Action to use condom

baselineref ref ref  ref 

  Month 6 0.172 <0.001 0.1916 <0.001  Month 12 0.143 0.001 0.1857 <0.001  Group 0.0174 0.678           Sexual initiation baseline ref ref ref  ref   Month 6 0.0746 <0.001 0.0694 <0.001  Month 12 0.148 <0.001 0.1318 <0.001  Group 0.1361 0.009   Condom use baseline ref ref ref   ref  Month 6 0.1727 <0.001 0.2660 <0.001  Month 12 0.2910 <0.001 0.3070 0.001  Group 0.0162 0.463

Intervention effect on the mean score : Male    INTERVENTION CONTROL

Variable Occasion Coefficient P-value Coefficient P-valueAction to delay sex baseline ref ref ref ref  Month 6 0.0839 0.004 0.1049 <0.001  Month 12 0.1497 <0.001 0.1562 <0.001  Group 0.003 0.633           Action to use condom

baseline ref ref ref ref  Month 6 0.0729 0.048 0.0546 0.173  Month 12 0.1880 0.019 0.0926 0.033  Group 0.0740 0.0876         Sexual initiation baseline ref ref ref ref  Month 6 0.0656 0.010 0.0272 0.530  Month 12 0.1249 0.007 0.0092 0.843  Group 0.1126 0.043           Condom use baseline ref ref ref ref  Month 6 0.3209 <0.001 0.1484 0.025  Month 12 0.3694 <0.001 0.2672 <0.001  Group 0.2173 0.004

ConclusionsThe intervention was effective in;

Promoting action plan to delay sex for both sexdelaying sexual initiation for both male and female adolescentsCondom use among male but not among women

Further analysisExamine intervention effectiveness in promoting other aspect of safer sex-multiple sexual partnersEffective on communication, self efficacy etcPredictors of observed positive outcomes