Methods | DESIGN: Single centre cluster RCT | |
LENGTH OF FOLLOW-UP: First follow-up conducted on average 1 month following graduation from training (i.e. end of the intervention) (median = 34.5 days, range = 11 to 146 days). Second follow-up conducted on average at 14 months after baseline assessment (median = 12.8 months, range = 6.2 to 31.7 months) | ||
DATA ANALYSIS: Not stated whether ITT or intervention received. From the results presented it appears that not all of the randomised participants were analysed at post-intervention | ||
ATTRITION RATE: At second follow-up 686 (64.5%) (intervention group) and 695 (63.4) (control group) completed the trial | ||
UNIT OF DATA ANALYSIS: Clusters (platoons) randomised, but individuals analysed | ||
SAMPLE SIZE CALCULATION: Assumed within-group cluster correlation was 0.01 based on 25 individuals per cluster to give sample size of 568 per group. Sample size was further increased to 1,000 participants per study group | ||
EQUIVALENT STUDY GROUPS AT BASELINE: Authors state that there were statistically significant differences between study groups on 4 variables (P = 0.006 to 0.043) . Intervention group more likely to be married, to ever had a casual sexual partner, to have used condoms <100% time and to have prior history of N.gonorrhoeae | ||
PROCESS EVALUATION: Not stated | ||
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Participants | NUMBER RANDOMISED: 2157 | |
AGE: Group 1: 17 to 18 years = 561 (52.8%); 19 to 21 years = 389 (36.6%); ≥ 22 years = 112 (10.5%). Group 2: 17 to 18 years = 603 (55.1%); 19 to 21 years = 391 (35.7%); ≥ 22 years = 101 (9.2%) | ||
SOCIO-ECONOMIC STATUS: Group 1: High school diploma or GED = 780 (73. 4%); Any college ofvocational/technical = 282 (26.6%). Group 2: High school diploma or GED = 829 (75.5%); Any college ofvocational/technical = 266 (24.3%) | ||
ETHINCITY/RACE: Group 1: Caucasian = 593 (55.8%); Latina = 211 (19.9 %); African American =165 (15.5%); Asian/Pacific Islander = 29 (2.7%); Native American = 29 (2.7%); Other or mixed = 35 (3.3%). Group 2: Caucasian = 613 (56.0%); Latina = 215 (19.6%); African American = 183 (16.7%); Asian/Pacific Islander = 38 (3.5%); | ||
Native American = 24 (2.2%); Other or mixed = 22 (2.0%) | ||
LOCATION: USA (California, Carolina). Group 1: Urban = 839 (79.1%); Rural = 222 (20.9%). Group 2: Urban = 860 (78.8%); Rural = 231 (21.2%) | ||
PREVIOUS STI (self-report): Group 1: Yes = 104 (11.6%); No = 789 (88.4%). Group 2: Yes = 105 (11.2%); No = 835 (88.8%) | ||
SEXUAL RISK BEHAVIOUR: | ||
Number of sexual partners (lifetime). Group 1: 1 partner = 149 (17.1%); ≥ 2partners = 722 (82.9%). Group 2: 1 partner = 174 (18.9%); ≥ 2 partners = 745 (81.1%) | ||
Frequency of condom use (lifetime). Group 1: <100% = 703 (80.3%); 100% = 173 (19. 7%). Group 2: <100% = 708 (76.7%); 100% = 215 (23.3 %) | ||
Other measures reported (but not extracted) were frequency ofcontraception use; number of casual partners (lifetime); history of pregnancy (self-report) and STI screening | ||
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Interventions | GROUP 1: Cognitive-behavioural intervention (n = 1062) | |
YEAR STARTED: 2000 | ||
PROVIDER(S): trained civilian research assistants (2x per session) | ||
SETTING(S): Not explicitly stated but participants were US female Marine recruits who received the intervention during their 13 week recruit training period | ||
TYPE: Information/Education to increase knowledge about risks for unintended pregnancy and STIs; Practical skill development (communication skills; condom use skills) | ||
DURATION: Four 2 hour sessions in weeks, 1,2,4 and 12 of the 13 week recruit training period | ||
THEORETICAL BASIS: Information, motivation and behavioural skills model (IMB) | ||
STIs COVERED: STIs in general, including HIV/AIDS | ||
GROUP 2: Health promotion control (n = 1095) | ||
YEAR STARTED: 2000 | ||
PROVIDER(S): As group 1 | ||
SETTING(S): As group 1 | ||
TYPE: Identical to Group 1 in educational strategies but designed to improve physical performance through healthier food choices, to reduce risk of sports or physical training injuries and examine risk and prevention of cervical and breast cancer in young women | ||
THEORETICAL BASIS: Not stated | ||
DURATION: As group 1 | ||
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Outcomes | PRIMARY: | |
Composite measure ofany STI or unintended pregnancy (UP). | ||
Any single measure of post-intervention STIs (C. trachomatis, N. gonorrhoeae, T. vaginalis) or UP | ||
SECONDARY: | ||
Sexual intercourse with multiple sex partners (two or more partners) | ||
Sexual intercourse with casual sexual partners inconsistent consistent condom use (100% versus <100%) | ||
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Notes | COST DATA: The only data given was for incentives to participate in the second follow-up assessment. They received a US$5.00 phone card or small gift bag containing cosmetics | |
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Risk of bias | ||
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Bias | Authors’ judgement | Support for judgement |
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Adequate sequence generation? | Low risk | Platoons (groups of 50 to 75 women) were randomly assigned to experimental intervention or control groups using a computer-generated random numbers table established before the start of the study |
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Allocation concealment? | Unclear risk | Not stated |
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Blinding? All outcomes |
Unclear risk | Not stated for biological outcomes (pri-mary outcome). Behavioural outcomes were self-report |
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Incomplete outcome data addressed? All outcomes |
Low risk | Second post-intervention questionnaires and biological screenings were conducted only in the 3 key regions where the female Marines were stationed, on grounds of cost. Those who were not stationed in the three regions only completed the questionnaires and did not undergo the biological screening. Thus, results for the primary outcome are based only on a sub-set of the randomised population. Not stated whether ITT or intervention received analysis was done. From the results presented it appears that not all of the randomised participants were analysed at post-intervention However, attrition rates were balanced between study groups and reasons for attrition were given (which did not differ between groups) |
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Free of selective reporting? | Low risk | Results for all outcome measures appear to have been reported |
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Free of other bias? | High risk | There were some imbalances in baseline variables between the trial groups which may bias the results (see under ‘Methods’) |