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Prevention of sexually transmitted HIV infection: a meta-analytic review of the behavioral outcome literature |
Kalichman S C, Carey M P, Johnson B T |
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Authors' objectives To evaluate the effectiveness of theory-based HIV risk reduction interventions for sexual behaviour change.
Searching The authors state that studies were obtained by searching computerised databases and handsearching relevant journals.
Study selection Study designs of evaluations included in the reviewRandomised field trials (sometimes stratified for age prior to randomisation) and non-randomised studies. Included studies had a comparison group and provided summary data or inferential statistics sufficient to calculate the relevant effect size.
Studies that presented open treatment trials or community level interventions were excluded.
Specific interventions included in the reviewHIV Risk-Reduction (HIV-RR) theory-based interventions which employed an HIV-RR intervention based on psychological theories of behaviour change and used group-based or face-to-face models of intervention delivery, with components of risk education, risk sensitisation, self-efficacy building, and skills training. Theory-based HIV-RR interventions are derived from social learning theory and emphasise observation, modelling, behavioural rehearsal, outcome expectancies, self-efficacy beliefs, and social reinforcement for instituting behaviour changes. The amount of information given in the interventions ranged from 2.3 to 20 hours in length, mostly delivered in 4 to 8 one- or two-hour sessions. The mean amount of information was 8.36 total hours. The intervention sessions were usually led by two or more adults.
Participants included in the reviewHomosexually-active men, inner-city women, runaway youth, college students, and chronically mentally ill adults. Study population was 51% male versus 49% female, aged between 14 and 39 years. Samples were 41% African-American, 25% White, 16% Hispanic, and 18% not classified.
Outcomes assessed in the reviewThe primary outcome measures were those that examined a behavioural HIV-RR outcome: number of sexual partners; number of protected and unprotected occasions of oral, anal, and vaginal intercourse; percentage of time that condoms are used; and/or engaging in sex with a high-risk partner. Other outcomes measured were: recently diagnosed sexually transmitted diseases (STDs); coercions into unwanted sexual activity; exchanging sex for money or drugs; or discussions with friends about sex.
How were decisions on the relevance of primary studies made?The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.
Assessment of study quality The authors do not report the method used to assess quality, or how the quality assessment was performed.
Data extraction The following data were extracted: population sampled, geographical site; gender composition of sample, mean age (in years) of sample participants, race of participants, study design, dosage or amount of intervention, number and sex of session leaders, components of intervention, type of control group, amount of control group information (where relevant), outcome measures assessed, attrition for intervention and follow-up assessments, and intervals (in months) for follow-up assessments. The authors do not state who performed the data extraction.
Individual effect sizes (g) were calculated with 95% confidence intervals (CIs). The g-statistic was defined as the difference between the means of the intervention and control groups on the behavioural outcome measure, divided by the pooled standard deviation. If means and standard deviations were not available then F- or t-statistics (with associated error terms) were used. The g effect size was converted to d for each case by correcting for bias. To reduce computational error, two of the authors calculated effect sizes independently and met to resolve discrepancies.
Methods of synthesis How were the studies combined?An overall estimate of effect size with 95% confidence interval (CI) was obtained by averaging the d statistics using a procedure that gives greater weight to effect sizes that are more reliably estimated.
How were differences between studies investigated?The authors tested for homogeneity using the chi-square statistic (Q). Moderator analyses of effect size magnitude followed Hedges and Olkin's procedures (see Other Publications of Related Interest) and yielded a test of the significance of each moderator (intervention dose, attrition rate, or the timing of the first post-intervention assessment).
Results of the review Twelve studies with 2,583 participants (average of 215 participants per study) were included in the review. Ten studies were randomised field trials, one of which (157 participants) was stratified for age prior to randomisation; and two studies were non-randomised in design.
All of the individual study effect sizes were positive (i.e. the intervention reduced risk) ranging from a small effect size of d = 0.11 to a moderate effect size of d = 0.53. The 95% CI for six of the studies achieved statistical significance, but these figures are not reported.
The combined effect size was statistically significant (d = 0.25, 95% CI: 0.18, 0.33).
The test for homogeneity indicated that there were not significant differences between the studies, Q(11) = 7.78, p > 0.50, and the positive trend for HIV-RR interventions is relatively constant across the methodological variations in the literature.
In the moderators analyses, dose (expressed in hours) and attrition were unrelated to intervention success, B = 0.51 and -0.04, ps > 0.15, respectively. Assessment interval was statistically significantly related to intervention success, B = -0.79, p < 0.05. As the interval between the intervention and the assessment increased, intervention success tended to decrease.
Authors' conclusions The behaviour interventions in this review show substantial promise for altering sexual behaviours associated with HIV transmission. The effect sizes observed in this review were small to moderate in size, but should be considered conservative estimates of intervention effects for several reasons, including moderate intervention doses and challenges to outcome measurement and subject retention. Behaviour change interventions such as those reviewed here remain the greatest hope for curtailing the spread of HIV.
CRD commentary The authors clearly state the research question and have listed inclusion and exclusion criteria for the review. Because the authors have failed to report the details of the literature search it is not possible to comment on the scope and quality of the search. The authors have not named the databases used in the search or the dates of the search and keywords used. The authors have also not stated whether there were any language restrictions. For these reasons, it is not possible to determine whether all relevant studies were retrieved.
The authors have not reported on how the articles were selected, or how the quality of the chosen studies was assessed. There was also no report as to who, or how many of the reviewers, selected the articles and extracted the data. Characteristics for the initial studies are reported in the review, but confidence intervals for the individual effect sizes were omitted.
The studies were combined in a statistical analysis of effect sizes using appropriate methods and heterogeneity was investigated in detail in the statistical analyses which suggested it was appropriate to combine the data. The results appear to support the authors' conclusions.
Implications of the review for practice and research Practice: The authors do not state any implications for practice.
Research: For the purposes of advising future theory-based HIV-RR studies, the authors suggest improvements for the methodological aspects of dose of intervention, outcome measures, behaviour change follow-up and attrition.
Funding National Institute of Mental Health, grant numbers P30-MH52776, RO!- MH53780, K21-MH01101, K21-MH01377.
Bibliographic details Kalichman S C, Carey M P, Johnson B T. Prevention of sexually transmitted HIV infection: a meta-analytic review of the behavioral outcome literature. Annals of Behavioral Medicine 1996; 18(1): 6-15 Other publications of related interest 1. Hedges LV, Olkin I. Statistical methods for meta-analysis. Orlando (FL): Academic Press; 1985.
Indexing Status Subject indexing assigned by CRD MeSH HIV Infections /prevention & Health Education; Sexual Behavior; control AccessionNumber 11997008428 Date bibliographic record published 31/03/2000 Date abstract record published 31/03/2000 Record Status 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. |
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