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Effects of HIV counseling and testing on sexual risk behavior: a meta-analytic review of published research, 1985-1997 |
Weinhardt L S, Carey M P, Johnson B T, Bickham N L |
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Authors' objectives To assess the effects of HIV counselling and testing (HIV-CT) on sexual risk behaviour.
Searching MEDLINE and PsycLIT were searched from January 1985 to June 1997 using combinations of the following keywords: 'AIDS', 'HIV' 'test*', 'counseling', 'serodiagnosis', 'serostatus', 'sex*' and 'behavior'. The authors also handsearched the journals AIDS, AIDS Care, AIDS Education and Prevention, American Journal of Public Health, Health Psychology, Journal of the American Medical Association, and Sexually Transmitted Diseases for the years 1985 to 1997 and scanned the reference lists of all identified articles for additional relevant studies. Unpublished studies were excluded from the review.
Study selection Study designs of evaluations included in the reviewFive study designs were included which assessed when, relative to data collection, participants underwent HIV-CT, which reported sexual behaviour outcome data or a proxy measure, had two or more assessments with the same participants, and which reported summary or inferential statistics sufficient for the calculation of within- group effect sizes (ES). Time elapsed prior to the first follow-up ranged from 16 days to 4 years (median 180 days).
Specific study designs were:
1. Cohort studies comparing behavioural data collected before and after antibody testing was introduced and assessing whether participants had been tested and the result (it is not clear whether the controls were historical).
2. Cohort studies comparing behavioural responses of participants whose blood was sampled for a study and who chose to receive test results and counselling with those of individuals who also had blood drawn but who chose not to receive test results.
3. Studies comparing behavioural data collected before and after testing was conducted among people who sought testing, people who were offered and accepted testing, or people in treatment for injection drug use.
4. Studies in which participants (who did not plan to be tested) were randomly assigned to testing or to a control group.
5. Studies comparing prenotification and postnotification behavioural data among people who tested HIV-positive when donating blood and received counselling with their test results.
Specific interventions included in the reviewCounselling and HIV testing (HIV-CT).
Participants included in the reviewAdult participants in HIV-CT programmes who were either HIV-positive, HIV-negative, or untested for HIV status. Participants mean age ranged from 23.0 to 39.1 years of age.
Outcomes assessed in the reviewNumber of sexual partners, condom use, unprotected intercourse and HIV and STD incidence.
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 No formal assessment of quality was undertaken. The authors discuss the validity of the studies.
Data extraction Two reviewers independently extracted the data. Reliability of the coding was evaluated for each category by computing K values for inter-rater agreement across all studies. Inter-rater agreement for data extraction/coding ranged from 0.81 to 1.00 (median 0.97). Discrepancies were resolved by discussion and further examination of the studies.
Data were extracted for descriptive and explanatory characteristics. Descriptive characteristics extracted were: year of publication, dates of data collection, and geographic location. Explanatory characteristics extracted were: educational attainment, race/ethnicity, sexual orientation, and identified risk group. Predictor variable characteristics were: number of participants who were tested, number who received a positive test result for HIV, number who received a negative test for HIV, and number who were untested. Counselling characteristics were: presence or absence of personalised risk assessment, inclusion of information about transmission routes, inclusion of information about preventative behaviour, explanation of HIV antibody testing, education about proper condom use, peer group discussion, partner notification, and number of minutes of pretest and posttest counselling. Sexual risk behaviour outcome variables characteristics were: level of measurement, type of risk behaviour, and length of reporting period. Potential moderators were also coded: sex of participants, average age of participants, volition for HIV-CT, HIV seroprevalence in sample, attrition rate, and length of follow-up.
For each study, within-group effect sizes (d+) (standardised mean difference) were calculated separately for each sexual behaviour outcome for each group (HIV-positive, HIV-negative, and untested participants; serodiscordant couples; and mixed samples). Effect sizes for serodiscordant couples and mixed samples were calculated separately because these two groups differ from the other three. Positive effect sizes indicated reductions in sexual risk behaviour.
Methods of synthesis How were the studies combined?Weighted mean effect sizes (d+) weighted on variance and 95% confidence intervals (CIs) were calculated using a fixed-effect model.
How were differences between studies investigated?The Q statistic was calculated to assess the homogeneity-of-variance of effect sizes. Variability in the magnitude of effect sizes was explained by relating the effect sizes to the studies' characteristics.
Categorical models, based on analysis of variance, and continuous models, based on least squares regression models, were evaluated to test relationships between study characteristics and outcomes.
Sensitivity analyses were conducted by computing fail-safe n's for group differences found in the primary analyses.
Results of the review Twenty-seven studies were included in the review with 19,597 participants. Sixty-eight percent of the studies reported attrition rates, which ranged from 5% to 89% (mean = 33%).
Number of sexual partners: (25 effect sizes) weighted mean effect size for the HIV-positive group was significantly positive (d+ = 0.34; 95% CI: 0.20, 0.47). The weighted mean effect size for the HIV-negative group (d+ = 0.20; 95% CI: 0.14, 0.26) was also positive and significant. Neither the HIV-positive group nor the HIV-negative group exhibited greater change than the untested group (d+ = 0.24, 95% CI: 0.17, 0.30). There was significant heterogeneity of effect sizes in each group. There was no data on numbers of sexual partners from studies of serodiscordant couples.
Unprotected intercourse: (21 effect sizes) weighted mean effect size for the HIV-positive group (d+ = 0.47; 95% CI: 0.32, 0.61) and the serodiscordant couple groups (d+ = 0.75, 95% CI: 0.59, 0.92) indicated significant risk reduction and both were greater than the weighted mean effect size for the untested participants (d+ = 0.16, 95% CI: 0.07, 0.25; p < 0.001). The HIV-negative participants (d+ = 0.19, 95% CI: 0.08, 0.31) did not reduce their frequency of intercourse relative to untested participants. Effect sizes in the untested and HIV-serodiscordant groups were homogeneous. Sensitivity analyses for the unprotected-intercourse outcome revealed that it would take seven studies with null results to reduce the serodiscordant-couple mean effect size to the same value as that for the untested participants, and it would take 10 studies with null results to reduce the mean effect size for the HIV-positive individuals to be statistically equivalent to that of the untested participants.
Condom use: (22 effect sizes) weighted mean effect size for the HIV- positive group (d+ = 0.65; 95% CI: 0.42, 0.87) and the serodiscordant couple groups (d+ = 1.31, 95% CI: 1.14, 1.48) were positive, significant, and homogeneous and both were greater than the weighted mean effect size for the untested participants (p < 0.001). The HIV- negative participants (d+ = 0.05, 95% CI: -0.02, 0.13) did not increase their condom use more than those who were untested (d+ = 0.15, 95% CI: 0.08, 0.17; p > 0.05). Sensitivity analyses for the condom-use outcome revealed that it would take 23 studies with null results to reduce the serodiscordant-couple mean effect size to the same value as that for the untested participants, and it would take 13 studies with null results to reduce the mean effect size for the HIV-positive individuals to be statistically equivalent to that of the untested participants.
HIV and STD incidence: (4 effect sizes) indicated that the incidence of STD infection decreased among HIV-positive participants (d+ = 0.15; 95% CI: 0.04, 0.26) but increased among HIV-negative participants (d+ = -0.17, 95% CI: -0.27, -0.06) and among untested participants (d+ = -0.05, 95% CI: -0.09, -0.01). The weighted mean effect size for HIV-positive participants was significantly greater than those for the HIV-negative participants and untested participants. In the one study presenting data on changes in HIV incidence from before and after HIV-CT, the effect did not differ from zero (d+ = 0.09, 95% CI: -0.01, 0.17).
Authors' conclusions The authors state that overall, HIV-positive participants and HIV- serodiscordant couples in the 27 studies examined reduced their frequency of unprotected intercourse and increased their condom use, relative to HIV-negative and untested participants, after receiving HIV counselling and testing. Furthermore, in two studies, HIV- positive participants exhibited reduced STD incidence relative to HIV-negative and untested participants. These findings indicate that HIV-CT is an effective secondary HIV prevention strategy; that is, participants who learned that they were HIV-positive did reduce their sexual risk behaviour, thereby decreasing their risk of subsequent re-infection and their risk of infecting others. Participants who received a negative HIV test result however, did not modify their sexual risk behaviour any more than individuals who did not participate in counselling and testing. Therefore, HIV-CT does not appear to be an effective primary prevention strategy.
CRD commentary This is a good review. The authors have clearly stated the research question and the inclusion and exclusion criteria. The literature search appears to be thorough. The quality of the included studies was not formally assessed but the authors have discussed the validity of the included studies at length. The authors have not reported how the articles were selected they do report how the data extraction was performed.
The data extraction is reported in tables and text and the statistical pooling of the study results was by weighted mean effect sizes, but it is difficult to provide a clinically meaningful interpretation from these figures. There were formal tests for heterogeneity and sensitivity, modelling and regression analyses on the results. The authors still pooled the data despite significant heterogeneity. The authors also narratively assess the heterogeneity between studies and other methodological and data limitations of the review. They specifically state that the heterogeneity of effect sizes and the number of significant moderators suggest that the participants' responses to HIV-CT are multiply determined and complex and this should be informed by greater use of social and behavioural theory. They also state that a limitation of the data is the absence of details about the counselling used in the studies which limits possible evaluations of the data. The authors' conclusions appear to follow from the results but should be viewed with caution because of the methodological limitation in the process of the review.
Implications of the review for practice and research Practice: The authors state that HIV-CT should be viewed as one part of an overall HIV prevention strategy that also includes individual-, community- and policy-level interventions.
Research: The authors state that theory-driven research is needed to further explicate the determinants of behaviour change in HIV-CT and research is also needed to examine the effectiveness of specific counselling approaches.
Funding National Institute of Mental Health, grant numbers K21-MH0110, K21- MH01377, F31-MH11125.
Bibliographic details Weinhardt L S, Carey M P, Johnson B T, Bickham N L. Effects of HIV counseling and testing on sexual risk behavior: a meta-analytic review of published research, 1985-1997. American Journal of Public Health 1999; 89(9): 1397-1405 Other publications of related interest This additional published commentary may also be of interest. Kamb ML, Peterman TA, Wolitski RJ. Prevention counseling for HIV-negative persons.American Journal of Public Health 2000;90(7):1152.
Indexing Status Subject indexing assigned by NLM MeSH AIDS Serodiagnosis; Adult; Age Factors; Condoms; Counseling /organization & Female; HIV Infections /prevention & HIV Seronegativity; HIV Seropositivity /psychology; HIV Seroprevalence; Health Knowledge, Attitudes, Practice; Humans; Male; Primary Prevention /organization & Program Evaluation; Risk-Taking; Sexual Behavior /psychology /statistics & Substance Abuse, Intravenous /complications; Treatment Outcome; administration; administration; control; numerical data AccessionNumber 11999009713 Date bibliographic record published 31/12/2000 Date abstract record published 31/12/2000 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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