|A systematic review of randomised controlled trials of interventions promoting effective condom use
|Free C, Roberts IG, Abramsky T, Fitzgerald M, Wensley F
The authors concluded that there was little reliable evidence on the effectiveness of condom promotion interventions. Several errors in the reporting of the review (discrepancies between tables, figures and text) made interpretation of the findings difficult. Despite some methodological concerns, the authors' conclusion reflects the very limited evidence presented and is likely to be reliable.
To evaluate interventions to promote effective condom use.
Cochrane Infectious Diseases Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, October 2006), MEDLINE, EMBASE, LILACS, IBSS (International Biography of Social Sciences) and PsycINFO were searched; search dates ranged from 1966 to 2006. Search terms were reported. Reference lists and conference proceedings were scanned. Researchers and field experts were contacted to retrieve further studies. There were no publication or language restrictions.
Randomised controlled trials (RCTs) of any intervention to promote effective condom use in men and women of any age were eligible for inclusion. Trials of female condoms or those comparing latex and non-latex condoms were excluded. The primary outcomes of interest were pregnancy and sexually transmitted infections. Eligible secondary outcomes were various measures of condom use (listed in the paper) and condom failure outcomes.
The participants in included trials were mainly young people, people with an sexually transmitted infection, intravenous drug users, men who had sex with men, psychiatric patients, and other high-risk individuals. Where reported, participants were recruited from healthcare, community, educational, and military settings. Most included trials did not report the ethnicity of participants. A wide variety of simple and complex interventions were included, most promoted individual sexual behaviour change. Other interventions promoted sexual and intravenous drug behavioural change, or focused on condom design (including the promotion of female condoms). A wide variety of outcome measures (mainly subjective) were included; most frequently reported were any sexually transmitted infection, self-reported pregnancy, and condom use at last sex.
Two independent reviewers selected the studies for inclusion.
Assessment of study quality
Trial quality was assessed with established criteria (Juni et al) covering sequence generation, allocation concealment, blinding, and loss to follow-up (10% or less was considered adequate). Trials that scored adequate on all four criteria were considered high quality.
Two independent reviewers carried out the quality assessment. Disagreements were resolved by discussion with a third reviewer.
Two independent reviewers extracted data to calculate odds ratios (ORs) or mean differences (MDs) and 95% confidence intervals (CIs). Data were extracted on whether clustering was taken into account in the analysis. Authors were contacted for unclear or missing information, where necessary. Disagreements were resolved by discussion with a third reviewer.
Methods of synthesis
A random-effects model was used to calculate odds ratios, standardised mean differences (SMDs), and 95% confidence intervals. Effect estimates for cluster randomised trials were calculated based on the intra-cluster correlation co-efficient (where reported), or the lowest of the published intra-cluster co-efficient in the review. The results of high quality trials were summarised separately. Statistical heterogeneity was assessed using X2 and I2. The influence of trial quality was explored. Publication bias was investigated using a funnel plot.
Results of the review
One hundred and thirty-nine RCTs (n=approximately143,000 participants) were included in the review. Eighty-seven trials provided sufficient data to calculate effect estimates. Four trials were considered to be high quality. Follow-up from randomisation was up to 26 weeks.
Sexual behaviour change interventions (23 RCTs): Pooled analysis showed a statistically significant reduction in any sexually transmitted infection (OR 0.79, 95% CI 0.66 to 0.94; 10 RCTs; I2=64%). Statistical heterogeneity was higher in trials with adequate allocation concealment and outcome assessor blinding. One high quality trial found a statistically significant reduction in self-reported sexually transmitted disease symptoms (OR 0.67, 95% CI 0.51 to 0.89). There were three statistically significant results amongst lower quality trials for other sexually transmitted infection outcomes: sexually transmitted disease reinfection (OR 0.57, 95% CI, 0.34 to 0.96; one RCT); chlamydia (OR 0.17, 95% CI 0.03 to 0.09; one RCT); and yearly gonorrhoea rate (RR 0.43, 95% CI 0.32 to 0.59; one RCT). here were no statistically significant effects on pregnancy outcomes. Statistically significant effects were reported in two high quality trials for uptake of condom provision or information in commercial and non-commercial sex settings, and for maintenance/improvement of safe sex behaviour in women.
Sexual and intravenous drug behaviour change interventions (24 RCTs): There were no high quality trials that evaluated pregnancy, sexually transmitted infection outcomes, or condom use. Nine of thirteen studies that reported condom use found higher levels in the intervention groups; this was statistically significant in three lower quality RCTs which showed reductions in the number of weeks without condom use, 100% condom use, or abstinence.
Condom design interventions (six RCTs): There were no trials evaluating pregnancy or sexually transmitted infection outcomes. One high quality trial found no significant difference between thicker and thinner condom failure rates.
Other results were reported in the paper.
There was little reliable evidence on the effectiveness of condom promotion interventions.
The review addressed a broad question; inclusion criteria were similarly wide in scope, although study design and outcomes provided elements of focus. The inclusion of two trials that evaluated female condoms contradicted the exclusion criteria. The search strategy included several relevant data sources. Attempts were made to maximise study retrieval whilst minimising publication and language biases. The review process was well-conducted, with evidence of attempts to minimise error and bias.
Trial quality was assessed using appropriate criteria, but full interpretation of this was not possible as the results were not accessible. The reported information suggested that the general quality of included trials was poor. Some trial characteristics were provided, but the reported fuller details online were not accessible. Several errors in the reporting of this review (discrepancies between tables, figures and text) made interpretation difficult.
Despite some methodological concerns identified above, the authors' conclusion reflects the very limited evidence presented and is likely to be reliable.
Implications of the review for practice and research
Practice: The authors stated that alternative means of condom distribution proximal to the time of sex should be evaluated, particularly among high-risk groups.
Research: The authors stated that high quality RCTs are needed to evaluate sexual behaviour change interventions based on content that is known to be effective. Further evaluation of the female reality condom was indicated. In general, consensus should be reached on the future design and reporting of trials, including the use of objective outcome measures and clear description of intervention content.
Free C, Roberts IG, Abramsky T, Fitzgerald M, Wensley F. A systematic review of randomised controlled trials of interventions promoting effective condom use. Journal of Epidemiology and Commmunity Health 2011; 65(2): 100-110
Subject indexing assigned by NLM
Condoms /supply & distribution /utilization; Databases, Bibliographic; Evidence-Based Practice; Female; Health Promotion /methods; Humans; Information Storage and Retrieval /methods; Male; Pregnancy; Pregnancy, Unwanted; Publication Bias; Randomized Controlled Trials as Topic /methods /standards /statistics & numerical data; Registries; Reproducibility of Results; Review Literature as Topic; Risk Reduction Behavior; Sexually Transmitted Diseases /prevention & control; Unsafe Sex /statistics & numerical data
Database entry date
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.