Concordance of chlamydia trachomatis infections within sexual partnerships.

OBJECTIVES: The enhanced sensitivity of nucleic acid amplification tests (NAAT) provides an opportunity for estimating the prevalence of untreated Chlamydia trachomatis infections. The transmissibility and public health significance of some NAAT-identified infections are, however, not known. METHODS: Adults attending an urban emergency department provided specimens for C trachomatis screening using NAAT. Participants testing positive were offered follow-up including re-testing for C trachomatis using NAAT and traditional methods, eg culture and direct fluorescent antibody, and were treated. Partners were offered identical evaluation and treatment. Overall, 90 C trachomatis-positive participants had one or more sexual partners enrolled. RESULTS: Evidence of transmission, as defined by infection concordance between partnerships, was observed among 75% of partners of index cases testing positive by both NAAT and traditional assay but only 45% of partners of index cases testing positive by NAAT only (prevalence ratio 1.7, 95% CI 1.1 to 2.5). Among index participants returning for follow-up, 17% had no evidence of C trachomatis infection by NAAT or traditional assay (median follow-up three weeks). CONCLUSIONS: A substantial proportion of positive NAAT results for chlamydial infection may be of lower transmissibility and may not persist after a short follow-up. The long-term health effects of some positive NAAT are uncertain.

Audio computer assisted interviewing to measure HIV risk behaviours in a clinic population.

OBJECTIVES: To examine whether audio computer assisted survey interviewing (ACASI) influenced responses to sensitive HIV risk behaviour questions, relative to interviewer administration of those questions (IAQ), among patients attending a sexually transmitted infection (STI) clinic and whether the impact of interview mode on reporting of risk behaviours was homogeneous across subgroups of patients (defined by age, sex, and previous STI clinic experience). METHODS: 1350 clinic patients were assigned to complete a detailed behavioural survey on sexual risk practices, previous STIs and symptoms, condom use, and drug and alcohol use using either ACASI or IAQ. RESULTS: Respondents assigned to ACASI were more likely to report recent risk behaviours such as sex without a condom in the past 24 hours (adjusted OR = 1.9), anal sex (adjusted OR = 2.0), and one or more new partners in the past 6 months (adjusted OR = 1.5) compared to those interviewed by IAQ. The impact of ACASI varied by sex but, contrary to expectations, not by whether the patient had previously visited an STI clinic. Mode of survey administration made little difference within this population in reports of STI knowledge, previous STIs, STI symptoms, or illicit drug use. CONCLUSION: ACASI provides a useful tool for improving the quality of behavioural data in clinical environments.

Monitoring STI prevalence using telephone surveys and mailed urine specimens: a pilot test.

OBJECTIVES: This pilot test assessed the feasibility of a cost effective population based approach to STI monitoring using automated telephone interviews, urine specimen collection kits sent out and returned by US Postal Service mail, and monetary incentives to motivate participation. METHODS: 100 residents of Baltimore, MD, USA, completed an automated telephone survey and agreed to mail in a urine specimen to be tested for chlamydia and gonorrhoea. Participants were paid dollar 10 for completing the survey and dollar 40 for mailing the specimen. RESULTS: 86% of survey participants mailed in a urine specimen for testing. CONCLUSIONS: Automated telephone surveys linked with testing of mailed-in urine specimens may be a feasible lower cost (relative to household surveys) method of estimating infection prevalences in a population.

LCR testing for gonorrhoea and chlamydia in population surveys and other screenings of low prevalence populations: coping with decreased positive predictive value.

OBJECTIVE: Nucleic acid amplification tests have facilitated field based STD studies and increased screening activities. However, even with highly specific tests, the positive predictive value (PPV) of such tests may be lower than desirable in low prevalence populations. We estimated PPVs for a single LCR test in a population survey in which positive specimens were retested. METHODS: The Baltimore STD and Behavior Survey (BSBS) was a population based behavioural survey of adults which included collecting urine specimens to assess the prevalence of gonorrhoea and chlamydial infection. Gonorrhoea and chlamydial infection were diagnosed by ligase chain reaction (LCR). Nearly all positive results were retested by LCR. Because of cost considerations, negative results were not confirmed. Predicted curves for the PPV were calculated for a single testing assuming an LCR test sensitivity of 95%, and test specificities in the range 95.0%-99.9%, for disease prevalences between 1% and 10%. Positive specimens were retested to derive empirical estimates of the PPV of a positive result on a single LCR test. RESULTS: 579 participants age 18-35 provided urine specimens. 20 (3.5%) subjects initially tested positive for chlamydial infection, and 39 (6.7%) tested positive for gonococcal infection. If positive results on the repeat LCR are taken as confirmation of a "true" infection, the observed PPV for the first LCR testing was 89.5% for chlamydial infection and 83.3% for gonorrhoea. This is within the range of theoretical PPVs calculated from the assumed sensitivities and specificities of the LCR assays. CONCLUSIONS: Empirical performance of a single LCR testing approximated the theoretically predicted PPV in this field study. This result demonstrates the need to take account of the lower PPVs obtained when such tests are used in field studies or clinical screening of low prevalence populations. Repeat testing of specimens, preferably with a different assay (for example, polymerase chain reaction), and disclosure of the non-trivial potential for false positive test results would seem appropriate in all such studies.

Reproductive choices for couples with haemophilia.

: Summary. The impact of having a child with an inherited bleeding disorder such as haemophilia can have a far-reaching effect on the individual as well as other close family members. This situation is further complicated in the case of human immunodeficiency (HIV) serodiscordant couples, where the haemophilic man is affected with HIV through infected blood products whilst his partner is seronegative and wanting to have children. It is essential that information on the effects of haemophilia, its inheritance, the possibilities of antenatal diagnosis, the consideration of selective abortion and the new reproductive opportunities available to these couples are made accessible so that an informed decision about proceeding with having a family can be made. Couples may wish to have a family through nonreproductive methods such as fostering or adoption. Alternatively, they may wish to remain childless. In this paper, the terms 'having children' and 'having a family' will refer to conception through biological reproduction. Pre-implantation genetic diagnosis (PGD) offers families at risk of having a child with certain inherited genetic disorders the opportunity to give birth to an unaffected child. It may be considered as an option for couples who would not wish to have prenatal diagnosis leading to possible termination of a pregnancy. Assisted conception techniques, such as 'sperm washing' or the use of 'donor sperm', offer serodiscordant couples affected by HIV a risk-reduced or risk-free opportunity, respectively, to have a child without infecting the mother, who could in turn infect the fetus by vertical transmission. This article, in addition to outlining the inheritance of haemophilia and the more common prenatal screening and diagnostic tests, discusses in more detail the latest reproductive opportunities available for families affected by haemophilia and considering having a family.

The impact of T-ACASI interviewing on reported drug use among men who have sex with men.

Measurements of drug use and other illicit or stigmatized behaviors are subject to nontrivial underreporting biases. During in-person surveys, respondents are more likely to report such behaviors when interviewed using techniques that maximize interviewee privacy, e.g., use of paper SAQs and audio-CASI rather than questioning by human interviewers. Until recently, respondents in telephone surveys could not be offered similar privacy. A new technology, telephone audio computer-assisted self-interviewing (T-ACASI) overcomes this limitation of telephone surveys by allowing respondents to respond to a computer. A randomized experimental test of T-ACASI was embedded in the Urban Men's Health Study (UMHS). UMHS surveyed a probability sample of 2,881 men from four United States cities and who reported having sex with men. Respondents interviewed using T-ACASI reported a higher prevalence of drug use and drug-related behaviors than respondents interviewed by human interviewers. However, survey respondents were more likely to break off an interview when the interview was conducted by a T-ACASI computer rather than by a human interviewer.

Audio-computer interviewing to measure risk behaviour for HIV among injecting drug users: a quasi-randomised trial.

BACKGROUND: We aimed to assess audio-computer-assisted self-interviewing (audio-CASI) as a method of reducing under-reporting of HIV risk behaviour among injecting drug users. METHODS: Injecting drug users were interviewed at syringe-exchange programmes in four US cities. Potential respondents were randomly selected from participants in the syringe exchanges, with weekly alternate assignment to either traditional face-to-face interviews or audio-CASI. The questionnaire included items on sociodemographic characteristics, drug use, and HIV risk behaviours for 30 days preceding the interview. We calculated odds ratios for the difference in reporting of HIV risk behaviours between interview methods. FINDINGS: 757 respondents were interviewed face-to-face, and 724 were interviewed by audio-CASI. More respondents reported HIV risk behaviours and other sensitive behaviours in audio-CASI than in face-to-face interviews (odds ratios for reporting of rented or bought used injection equipment in audio-CASI vs face-to-face interview 2.1 [95% CI 1.4-3.3] p=0.001; for injection with borrowed used injection equipment 1.5 [1.1-2.2] p=0.02; for renting or selling used equipment 2.3 [1.3-4.0] p=0.003). INTERPRETATION: Although validation of these self-reported behaviours was not possible, we propose that audio-CASI enables substantially more complete reporting of HIV risk behaviour. More complete reporting might increase understanding of the dynamics of HIV transmission and make the assessment of HIV-prevention efforts easier.

Monitoring the health status and impact of treatment on Americans: the Medicare Beneficiary Health Status Registry.

OBJECTIVE: A major new survey program, the Medicare Beneficiary Health Status Registry (MBHSR), has been proposed to improve the monitoring of the health status of Medicare beneficiaries. The MBHSR would collect data by mail with telephone follow up of nonrespondents to permit economical assessment of a total Registry of approximately 200,000 Medicare beneficiaries, approximately 54,000 of whom would be surveyed in any given year. (Surveys would be conducted of samples of new enrollees who would be reinterviewed every five years.) METHOD: To assess the feasibility of that approach, a field test was conducted with a probability sample (n = 1,922) that comprised approximately equal numbers of new Medicare enrollees (aged, 65) and current beneficiaries (age range, 76-80). The field test was designed to assess the quality of the data that this design would produce. FINDINGS: Results indicate that the proposed design of the MBHSR could achieve response rates of approximately 80% among both age cohorts using a survey instrument that took 30 minutes to complete. Internal reliability of Activities of Daily Living, Instrumental Activities of Daily Living, Mobility, Mental Health Index, General Health, and Prostate Symptomatology scales ranged from 0.77 to 0.93. When measurements were repeated approximately 30 days after the initial survey, moderate to high levels of cross temporal correlation (range, 0.64-0.96) were found for most indexes, with the exception of prostate symptomatology. In addition, an earlier comparison of survey responses in the MBHSR field test to Medicare payment records indicated that the MBHSR field test obtained highly accurate reports of most of the major surgeries that were recorded in Medicare claims files. CONCLUSION: The design proposed for the MBHSR is feasible. If implemented, it should produce acceptably high rates of response and data quality.

Correlates of sexually transmitted bacterial infections among U.S. women in 1995.

CONTEXT: Sexually transmitted diseases (STDs) of bacterial origin such as gonorrhea and chlamydial infection can lead to pelvic inflammatory disease (PID) and infertility. Identifying behaviors and characteristics associated with infection may assist in preventing these often asymptomatic diseases and their sequelae. METHODS: Data from 9,882 sexually active women who participated in the 1995 National Survey of Family Growth describe the characteristics of women who report a history of infection with a bacterial STD or of treatment for PID. Multivariate analysis is used to determine which demographic characteristics and sexual and health-related behaviors affect the likelihood of infection or the occurrence of complications. RESULTS: Overall, 6% of sexually active women reported a history of a bacterial STD, and 8% reported a history of PID. Women who first had sexual intercourse before age 15 were nearly four times as likely to report a bacterial STD, and more than twice as likely to report PID, as were women who first had sex after age 18. Having more than five lifetime sexual partners also was associated with both having an STD and having PID. PID was more common among women reporting a history of a bacterial STD (23%) than among women who reported no such history (7%). In multivariate analyses, age, race, age at first intercourse and lifetime number of sexual partners had a significant effect on the risk of a bacterial STD. Education, age, a history of IUD use, douching and a history of a bacterial STD had a significant impact on the risk of PID, but early onset of intercourse did not, and lifetime number of partners had only a marginal effect. CONCLUSIONS: The pattern of characteristics and behaviors that place women at risk of infection with bacterial STDs is not uniform among groups of women. Further, the level of self-reported PID would suggest higher rates of gonorrhea and chlamydial infection than reported.

Effects of interview mode on bias in survey measurements of drug use: do respondent characteristics make a difference?

Three recent empirical studies have provided strong evidence that self-administered questionnaires (SAQs), compared with interviewer questioning, substantially improve the reporting of drug use in population surveys. Specifically, SAQs appear to diminish underreporting bias. Two of these studies previously reported that this effect of interview mode varied significantly across gender, race/ethnicity, and age. Data from a randomized experiment embedded in the 1990 National Household Survey of Drug Abuse (NHSDA) field test were reanalyzed to test for those interaction effects. To better replicate prior studies, the NHSDA field test sample was restricted to people ages 18 to 45 (N = 1,877). The results of our statistical analyses generally replicated the finding of a main effect of SAQs on the reporting of drug use. However, only weak evidence was found to support the hypothesis that the advantage of SAQs varies substantially by the gender, race/ethnicity, or age of the respondent.

Changes in sexual behavior and condom use among teenaged males: 1988 to 1995.

OBJECTIVES: This study examines shifts in sexual experience and condom use among US teenaged males. METHODS: Results from the 1988 and 1995 National Surveys of Adolescent Males were compared. RESULTS: The proportion of never-married 15- to 19-year-old males who had had sex with a female declined from 60% to 55% (P = .06). The share of those sexually active using a condom at last intercourse rose from 57% to 67% (P < .01). Overall, the proportion of males who had sex without condoms last year declined from 37% to 27% (P < .001). CONCLUSIONS: Although protective behaviors among teenagers have increased, significant proportions of teenagers--especially Black and Hispanic males--remain unprotected.

Adolescent sexual behavior, drug use, and violence: increased reporting with computer survey technology.

Surveys of risk behaviors have been hobbled by their reliance on respondents to report accurately about engaging in behaviors that are highly sensitive and may be illegal. An audio computer-assisted self-interviewing (audio-CASI) technology for measuring those behaviors was tested with 1690 respondents in the 1995 National Survey of Adolescent Males. The respondents were randomly assigned to answer questions using either audio-CASI or a more traditional self-administered questionnaire. Estimates of the prevalence of male-male sex, injection drug use, and sexual contact with intravenous drug users were higher by factors of 3 or more when audio-CASI was used. Increased reporting was also found for several other risk behaviors.

Zenilman's anomaly reconsidered: fallible reports, ceteris paribus, and other hypotheses.

BACKGROUND AND OBJECTIVES: In the January-February, 1995 issue of Sexually Transmitted Diseases, Zenilman and colleagues reported a null association between incident sexually transmitted diseases (STDs) and self-reported condom use. That anomalous finding generated a flurry of letters to the editor, some of which were quite heated. This article reconsiders the Zenilman team's results. STUDY DESIGN: New statistical analyses were conducted to test two hypotheses that sought to account for the null association: (1) deviation from study protocol, and (2) differential risks of acquiring an incident STD among segments of the study population that varied by reported level of condom use. RESULTS: No support was found for hypotheses concerning deviation from study protocol and differential risk of acquiring an incident STD by level of condom use. Indeed, for respondents who reported multiple sexual partners, the analyses found increased rates of infection among those who reported more consistent condom use. CONCLUSIONS: Two of the most promising hypotheses for explaining Zenilman's anomalous findings are unsupported by reanalysis of the available empirical evidence. It is still possible that respondents who reported that they used condoms consistently differed from self-reported nonusers or inconsistent users in some way that altered their risk of acquiring an STD and thus obscured the protective effects of properly used condoms. Nonetheless, as Zenilman and others suggest, fallibility in self-reports of condom use remains the primary suspect as the cause of these anomalous results. Such fallibility may be particularly pronounced when self-reported behavioral data are collected in contexts that include strong educational campaigns or other norm-setting interventions.

The promise of integrated representative surveys about sexually transmitted diseases and behavior.

BACKGROUND: It has been difficult to conduct representative surveys measuring both sexually transmitted disease prevalence and behavioral data. This article reviews the literature, describes a recent pretest of the feasibility of integrated surveys, and discusses the potential implications. METHODS: Several national surveys are reviewed, including the National Health and Nutrition Examination Surveys, National Health and Social Life Survey, and National Survey of Adolescent Males. The 1994 pretest of the National Survey of Adolescent Males collected urine specimens of male respondents, which were tested for Chlamydia trachomatis using ligase and polymerase chain reaction tests. RESULTS: There have not been any prior national surveys that collect clinical measures of STD infection and detailed behavioral data. In the pretest, 85% of the eligible interview respondents provided a urine specimen. Of those tested, 6% were positive for C. trachomatis. CONCLUSIONS: Combining behavioral surveys with collection of urine specimens for STD testing in representative samples is feasible. However, STD testing adds new operational and ethical challenges to the conduct of household surveys.

The quality of health data obtained in a new survey of elderly Americans: a validation study of the proposed Medicare Beneficiary Health Status Registry (MBHSR).

The Medicare Beneficiary Health Status Registry (MBHSR) is a proposed new survey program that would collect health status indicators annually from large probability samples of Medicine beneficiaries. For reasons of economy, the MBHSR would use mail survey procedures with telephone follow-up of nonrespondents. Because of concerns about response rates and the validity and reliability of the data obtained by such methods, a large-scale (N = 1,922) field test was conducted. The field test assessed the validity of MBHSR survey reports of past medical treatment and conditions by comparing those reports with Medicare claims data. It assessed the (internal) reliability of MBHSR survey responses by comparing responses with logically related survey questions from the MBHSR. Analyses indicate that the MBHSR survey procedures using a combination of mail data collection with telephone follow-up of nonrespondents produced relatively high levels of sensitivity and specificity in identifying medical treatments and procedures previously recorded in Medicare claims data. In addition, the MBHSR Field Test obtained, in general, relatively high levels of internal consistency in survey reports.

Monitoring trends in drug use: strategies for the 21st century.

Since the 1970s the United States and other nations have conducted regular statistical monitoring of the prevalence and patterns of drug use in their populations. Given the importance of such surveys for policymaking, their quality is a critical issue, and the biases that may affect their measurements become a major concern. An increasing volume of empirical evidence shows that the mode of administration of a survey can strongly influence the validity of respondents' reports. Compared with interviewer-administered questionnaires, self-administered forms appear to elicit more complete reporting of drug use, but the challenges they pose to the literacy skills of respondents may result in measurement biases. In addition, processes of social change may confound true shifts in drug use with changes in the willingness of respondents to report such use. The authors propose several strategies to improve monitoring of trends in drug use. Those approaches include 1) more frequent use of a survey technology--audio computer-assisted self-interviewing--that ensures full privacy for all survey respondents but does not require literacy; 2) increased use of time-series of indicators of drug use consequences built from blinded surveys of medical records; and 3) population-based surveys that collect biological specimens (e.g., hair samples). Data from the latter two sources are not subject to the same constellation of biases that afflict self-reports of drug use. Time-series of those data can be integrated with self-reports to provide a better understanding of changes over time in the prevalence and patterns of drug use.

Quality of treatment data. Reliability over time of self-reports given by clients in treatment for substance abuse.

This study examines the reliability over a 2-month period of self-reports of drug use, sexual behaviors, and use of treatment services provided by 2,968 clients participating in a large, multisite, prospective study of drug treatment in the United States-the Drug Abuse Treatment Outcome Study (DATOS). Analyses focus on responses to 62 pairs of logically related questions that were asked at two points in time: (1) 1 month after entry into treatment, and (2) 3 months after entry into treatment. Subjects' responses to questions asked at these two time points are assessed for logical consistency. Prior analyses of self-reports provided by DATOS clients at one point in time (entry into treatment) found surprisingly high levels of within-interview consistency in their reporting of alcohol use (Turner & Hubbard, 1995) and cocaine use (Adair, Craddock, Miller, & Turner, 1995). The crosstemporal tests of consistency reported in this article eliminate several potential sources of artifactual consistency that may have affected prior analyses, (e.g., consistency imposed by an interviewer or constructed by a respondent during the course of a single interview). Contrary to expectations, crosstemporal comparisons reveal high levels of logical consistency in clients' responses. The mean percent of substantively inconsistent responses ranges from 0.7% for questions asking about frequency of drug use to 4.4% for questions asking about sexual behaviors.

Assessing consistency of responses to questions on cocaine use.

This study examines consistency of self-reported responses to items within the questionnaire of a multi-site, prospective study of drug abuse treatment in the United States (DATOS). The analyses use data from 2842 interviewer-administered intake interviews. Questions that were logically related are paired and responses compared. The questions cover three topics: (1) age at which different types of cocaine was used, (2) reports on most recent use and (3) frequency of cocaine use during period of "heaviest" use. Responses are coded as consistent, inconsistent, or as survey administration error. The latter is related to interviewer errors such as erroneous skip pattern, out-of-range responses, "don't know" responses, missing data, or illegible responses. Contrary to expectations inconsistent responses were relatively rare in this study, with fewer than 5% (0.5-4.6%) of respondents reporting inconsistent answers for pairs of logically related questions. A careful review of responses also found few survey administration errors (0.2-1.3%).

Quality of alcohol use histories collected at intake to substance user treatment.

Many survey questions on alcohol require complex cognitive tasks, such as long-term recall, shifting reference periods, and numeric calculation. Moreover, alcohol-related impairment is known to affect cognitive ability. To assess the quality of data on self-reported alcohol use, internal consistency analyses were conducted as part of a comprehensive multisite prospective study of drug user treatment outcome undertaken in 11 cities throughout the United States (DATOS). Contrary to expectation, analyses found high levels of internal consistency. For questions on age of initiation of different types of alcohol use, over 99% of respondents (N = 2,842) reported consistent answers for each pair of logically related questions. Reports of being drunk and of quantity of alcohol consumed were similarly consistent.