Patterns of HIV testing among Ontario physicians

OBJECTIVE

HIV testing is important for HIV prevention and control. Nevertheless, approximately 35% of HIV infections in Ontario remain undiagnosed. We examined patterns of HIV testing among physicians to determine provider-related factors associated with HIV testing in Ontario.

METHODS

Providers identified from HIV test requisitions submitted to the Ontario Public Health Laboratory in 2006 were linked to a database of Ontario physicians using probabilistic matching. We examined HIV testing frequency by demographic characteristics and physician specialty. In multivariate logistic regression, we assessed factors associated with high testing frequency (20+ tests).

RESULTS

12,477 physicians (59.3% of Ontario physicians) prescribed at least one HIV test in 2006; the proportion was highest in Central East/other (72.4%) and Northern (69.4%) regions compared to others (53.7-58.7%), and highest among the most recent graduates (68.4% versus 59.0% among earlier graduates). A substantial proportion of physicians in family medicine/general practice (83.6%), obstetrics/gynecology (82.1%) and internal medicine (47.7%) prescribed HIV testing. Overall, most physicians (67.5%) prescribed fewer than 20 tests. High testing frequency was significantly associated with practice in Toronto (AOR 2.95), Central East/other (AOR 2.02), or Ottawa region (AOR 2.28), and specialty in family medicine/general practice (AOR 11.47), obstetrics/gynecology (AOR 6.31) or internal medicine (AOR 1.37). Physician sex and graduation country were not associated with high testing in multivariate regression. Of 361,609 tests, 1,048 (0.29%) were HIV-positive; 436 physicians (3.5%) had at least one HIV-positive result.

CONCLUSION

HIV testing among Ontario physicians varied substantially by health region, graduation year and specialty. These factors should be considered when delivering continuing medical education on HIV testing.

Accuracy of serological assays for detection of recent infection with HIV and estimation of population incidence: a systematic review

We systematically reviewed the accuracy of serological tests for recent infections with HIV that have become widely used for measuring population patterns incidence of HIV. Across 13 different assays, sensitivity to detect recent infections ranged from 42-100% (median 89%). Specificity for detecting established infections was between 49.5% and 100% (median 86.8%) and was higher for infections of durations longer than 1 year (median 98%, range 31.5-100.0). For four different assays, comparisons were made between assay-derived population incidence estimates and a reference incidence estimate. The median percentage difference between the assay-derived incidence and reference incidence was 26.0%. Serological assays have reasonable sensitivity for the detection of recent infection with HIV, but are vulnerable to misclassifying established infections as recent-potentially leading to biases in incidence estimates. This conclusion is highly qualified by the apparent absence of a standardised approach to assay evaluation. There is an urgent need for an internationally agreed framework for evaluating and comparing these tests.

Prenatal HIV testing: women's experiences of informed consent in Toronto, Ontario

OBJECTIVE

All Canadian jurisdictions have human immunodeficiency virus (HIV) testing programs requiring that clinicians discuss HIV testing with all pregnant women and seek their consent to be tested. Our goal was to evaluate how the informed consent process was being carried out in Ontario.

METHODS

Between November 2002 and February 2004, women in postpartum wards in three Toronto teaching hospitals were invited to participate in the study. A structured questionnaire was administered on the ward, medical records were reviewed, and data from the Central Public Health Laboratory were examined to verify whether or not the women had been tested.

RESULTS

Of 446 women invited, 299 (67%) participated. All except one participant had at least one prenatal visit, and 92% had more than five visits. Seventy-four percent of participants recalled a clinician talking to them about testing, and 70% of these felt that they were given the option to refuse the test. Twenty-one women overall (7%) believed that they were not tested during pregnancy or were not certain whether they had been tested or not, but actually had been tested. Women who felt that their care provider did not have an opinion about whether they should undergo testing were more likely to decline. Eighty-six percent were completely satisfied with the testing experience.

CONCLUSION

Informed consent for prenatal HIV testing is generally being obtained in a manner consistent with provincial guidelines. Our findings raise concern, however, that a significant number of women are not offered testing or in some cases are tested without their consent. Increases in testing rates could be achieved by offering the test to all women and emphasizing that carrying out testing is a recommended part of medical care.

Determinants of HIV seroconversion among men who have sex with men living in a low HIV incidence population in the era of highly active antiretroviral therapies

OBJECTIVE

To estimate human immunodeficiency virus (HIV) incidence and associated risk factors among men who have sex with men (MSM) participating in the Omega Cohort Study in Montreal, 1996-2003.

METHODS

Longitudinal study of 1587 MSM seronegative at baseline with > or =1 six-month follow-up visit. Multivariate Cox regression with time-dependent variables was used for data analysis.

RESULTS

HIV incidence was 0.62 per 100 person-years (95% confidence interval: 0.41-0.84). In multivariate analyses compared with subjects not reporting any anal sex with serodiscordant or casual partners, those reporting anal sex with such partners (all P values <0.05), whether consistently protected [hazard ratio (HR) = 3.4], or unprotected exclusively receptive (HR = 12.0), exclusively insertive (HR = 4.7), or both receptive and insertive (HR = 8.3), were at increased risk of seroconversion. Sexual behaviors with seroconcordant regular partners were not associated with seroconversion.

CONCLUSION

These results observed in a cohort of MSM with low HIV incidence provide new insights regarding the debate about harm-reduction strategies to prevent sexual HIV transmission.

HIV and ethnicity in Canada: is the HIV risk-taking behaviour of young foreign-born MSM similar to Canadian born MSM?

There is a dearth of information on the HIV risk-taking behaviour of foreign-born men who have sex with men (MSM) in Canada. This study focused on identifying sexual risk behaviour among MSM who immigrated to Canada and compared them to MSM who were born in Canada. Baseline data from the Omega Cohort in Montreal and the Vanguard Project in Vancouver were combined to form four ethnicity/race analytical categories (n = 1,148): White born in Canada (WBIC), White born outside of Canada, non-White born in Canada (NBIC) and non-White born outside of Canada (NBOC). Psychological, demographic and sexual behaviour characteristics of the groups were similar except: NBOC were more likely to be unemployed, less likely to be tattooed, had fewer bisexual experiences and less likely worried of insufficient funds. WBOC were more likely to report unprotected sex with seropositives and more likely to have had unprotected sex while travelling. NBIC were more likely to have ever sold sex and to have had body piercing. WBOC are at high risk of acquiring as well as transmitting HIV. It is important to consider place of birth in addition to ethnicity when developing programmes to prevent the transmission of HIV.

Medical Records and Women’s Self-Report Are Not Reliable Sources for Determining Whether Prenatal HIV Testing Was Done

OBJECTIVE

To determine whether medical records and the self-report of a postpartum patient provide reliable information about whether or not prenatal HIV testing has been done.

METHODS

Women on the postpartum wards at three Toronto teaching hospitals who gave informed consent were included in the study. The presence or absence of prenatal HIV testing was determined by interviews with postpartum women, review of hospital charts, and search of the Public Health Provincial Laboratory and Prenatal Testing databases.

RESULTS

Two hundred ninety-nine women were enrolled. All had had at least one prenatal visit, and 92% had copies of prenatal records in their hospital charts. Health records and patient reports were both unreliable for determining who had and who had not had HIV testing. HIV status was documented on 55% of the charts; on 46% it was noted that testing was performed, and on 46% there was documentation of pre& or post&test counselling. In interviews, 73% of the women reported having an HIV test during this pregnancy. Using the laboratory databases as the gold standard of whether testing had truly been done, medical record sensitivity and specificity were 65% and 62% respectively, and self-report sensitivity and specificity were 87% and 52% respectively. Using medical records resulted in an underestimation and self-reports an overestimation of the number of women who had been tested.

CONCLUSIONS

Both medical records and patient self-report are unreliable at the time of labour and delivery for determining whether or not a woman has been tested for HIV in pregnancy. Clinical and public health decisions may therefore be compromised by a lack of accurate testing information at the bedside.

Nonnegligible increasing temporal trends in unprotected anal intercourse among men who have sexual relations with other men in montreal

OBJECTIVE

To determine temporal trends in unprotected anal intercourse (UAI) among men who have sex with men (MSM) participating in the Omega Cohort Study, 1997 through 2003.

METHODS

The Omega Cohort Study was a longitudinal study of HIV-negative MSM aged 16 years or older and living in Montreal. Participants completed self-administered questionnaires and interviews every 6 months. Trend analysis using the generalized estimating equation was done for length of cohort membership (visits) and by calendar time for all visits per type of sexual partner. Odds ratios (ORs) were calculated to measure the odds of increasing UAI per 6-month period.

RESULTS

Among subjects who were followed for at least 4 years, UAI increased with regular seroconcordant partners (OR = 1.06, 95% confidence interval [CI]: 1.04 to 1.09) and any type of partner (OR = 1.05, 95% CI: 1.03 to 1.07). There was a nonnegligible increase in UAI with casual partners (OR = 1.05, 95% CI: 1.01 to 1.09). For the analysis by calendar time, there were increases in UAI between regular seroconcordant partners (OR = 1.04, 95% CI: 1.02 to 1.05) and any type of partner (OR = 1.03, 95% CI: 1.02 to 1.04). There were nonnegligible increases in UAI with casual partners (OR = 1.03, 95% CI: 1.00 to 1.05) and with any type of partner except a regular seroconcordant partner from 15.7% to 18.8% (OR = 1.02, 95% CI: 1.00 to 1.04).

CONCLUSIONS

There was a nonnegligible and consistent increase in UAI among Omega Cohort Study participants between 1997 and 2003. Continuous trend analysis is important because it allows us to follow UAI closely and to implement intervention strategies that may help to stop or reduce the present trend.

Trends in HIV-1 in young adults in south India from 2000 to 2004: a prevalence study

BACKGROUND

Major increases in HIV-1 prevalence in India have been predicted. Incident infections need to be tracked to understand the epidemic's course, especially in some southern states of India where the epidemic is more advanced. To estimate incidence, we investigated the prevalence of HIV-1 in young people attending antenatal and sexually transmitted infection (STI) clinics in India.

METHODS

We analysed unlinked, anonymous HIV-1 prevalence data from 294 050 women attending 216 antenatal clinics and 58 790 men attending 132 STI clinics in 2000-04. Southern and northern states were analysed separately.

FINDINGS

The age-standardised HIV-1 prevalence in women aged 15-24 years in southern states fell from 1.7% to 1.1% in 2000-04 (relative reduction 35%; p(trend)<0.0001, yearly reduction 11%), but did not fall significantly in women aged 25-34 years. Reductions in women aged 15-24 years were seen in key demographic groups and were similar in sites tested continuously or in all sites. Prevalence in the north was about a fifth of that in the south, with no significant decreases (or increases) in 2000-04. Prevalence fell in men aged 20-29 years attending STI clinics in the south (p(trend)<0.0001), including those with ulcerative STIs (p(trend)=0.0008), but reductions were more modest in their northern counterparts.

INTERPRETATION

A reduction of more than a third in HIV-1 prevalence in 2000-04 in young women in south India seems realistic, and is not easily attributable to bias or to mortality. This fall is probably due to rising condom use by men and female sex workers in south India, and thus reduced transmission to wives. Expansion of peer-based condom and education programmes for sex workers remains a top priority to control HIV-1 in India.

Nonnegligible Increasing Temporal Trends in Unprotected Anal Intercourse Among Men Who Have Sexual Relations With Other Men in Montreal

OBJECTIVE

The objective of this study is to determine temporal trends in unprotected anal intercourse (UAI) among men who have sex with other men (MSM) participating in the Omega Cohort Study, 1997-2003.

METHODS

The Omega Cohort Study was a longitudinal study of HIV-negative MSM aged 16 years or older and living in Montreal. Participants completed self-administered questionnaires and interviews every 6 months. Trend analysis using the generalized estimating equation was done for length of cohort membership (visits) and by calendar time for all visits, per type of sexual partner. Odds ratios (ORs) were calculated to measure the odds of increasing UAI per 6-month period.

RESULTS

Among subjects who were followed for at least 4 years, UAI increased with regular seroconcordant partners (OR, 1.06, 95% CI 1.04-1.09), and any type of partner (OR, 1.05, 95% CI 1.03- 1.07). There was a nonnegligible increase in UAI with casual partners (OR, 1.05; 95% CI, 1.01-1.09). For the analysis by calendar time, there were increases in UAI between with regular seroconcordant partners (OR, 1.04; 95% CI, 1.02-1.05) and any type of partner (OR, 1.03; 95% CI, 1.02-1.04). There were nonnegligible increases in UAI with casual partners (OR, 1.03; 95% CI, 1.00-1.05) and with any type of partner except regular seroconcordant partner from 15.7% to 18.8% (OR, 1.02; 95% CI, 1.00-1.04).

CONCLUSIONS

There was a nonnegligible and consistent increase in UAI among Omega participants, between 1997 and 2003. Continuous trend analysis is important because it allows us to closely follow UAI and to implement intervention strategies that may help to stop or reduce the present trend.

Sexual risk behaviour of Canadian participants in the first efficacy trial of a preventive HIV-1 vaccine

BACKGROUND

Phase I and phase II HIV-1 vaccine trials have revealed increases in risky sexual activity among study subjects during the trials, perhaps because the subjects believe that the vaccine being tested is efficacious; subjects may thus suffer harm from their participation. We evaluated the sexual behaviour of Canadian men who have sex with men (MSM) who participated in the phase III Vax004 trial of an HIV-1 vaccine.

METHODS

Using self-reports of sexual behaviours during the 6 months before trial entry as a baseline, we determined changes in reported sexual behaviour after 6, 12 and 18 months of participation in the trial.

RESULTS

Of 291 HIV-seronegative MSM enrolled from July to October 1999, 260 (89%) completed 18 months of follow-up, 19 (7%) experienced seroconversion, and 12 (4%) did not complete follow-up. Unprotected receptive anal intercourse during the previous 6 months with partners whose HIV-1 serostatus was positive or unknown was reported by 21% of men at enrollment and by 27% at any point during 18 months of follow-up. No increase in this behaviour from baseline was reported by participants, including among men who were motivated to enroll because of expected protection from HIV-1 infection, men who believed they had received the vaccine, men who believed that the vaccine had greater than 50% efficacy, or men who believed that they had received the vaccine and that vaccine efficacy was greater than 50%.

INTERPRETATION

MSM can be successfully enrolled in HIV-1 vaccine efficacy trials without evident increases in those sexual behaviours most associated with HIV-1 risk.

Potential cost-effectiveness of a preventive hepatitis C vaccine in high risk and average risk populations in Canada

Hepatitis C virus (HCV) vaccine development remains at an early stage. We explored the economic and health consequences of potential HCV vaccines by comparing universal vaccination with a hepatitis C vaccine to no vaccination in two groups: (1) injecting drug users (IDU); (2) all 12 year olds, using a Markov cohort simulation. Among IDUs, vaccination would avert 248 cases of HCV infection and 89 HCV-related deaths per 1000 individuals, and reduce costs. In average risk cohorts, vaccination did not reduce costs but was reasonably cost effective. These results provide encouragement to vaccine developers that a vaccine that is moderately effective and reasonably priced should not face economic barriers to implementation and will be attractive to third party payers.

Lack of evidence of sexual transmission of hepatitis C virus in a prospective cohort study of men who have sex with men

OBJECTIVES

We studied the prevalence and incidence of hepatitis C virus (HCV) infection in the ongoing Omega Cohort Study of men who have sex with men (MSM).

METHODS

From January to September 2001, consenting men (n = 1085) attending a follow-up visit to the ongoing Omega Cohort Study were tested for HCV. If the test results were positive for HCV, we compared them with test results from previous serum samples collected from the time of entry into the original cohort study to determine the time of infection.

RESULTS

HCV prevalence at entry was 2.9% and was strongly associated with injection drug use (32.9% vs 0.3%, P<.0001). Only 1 seroconversion was identified in 2653 person-years of follow-up (incidence rate = 0.038 per 100 person-years). The seroconverter was an active injection drug user who reported needle sharing.

CONCLUSIONS

Sexual transmission of HCV among MSM appears to be rare.

Factors associated with a decrease in the prevalence of drug resistance in newly HIV-1 infected individuals in Montreal

OBJECTIVE

A decrease in the prevalence of drug resistance (DR) has been observed among recently infected (RI) individuals in Montreal. A study of chronically infected (CI) patients, who represent potential HIV-1 transmitters, was carried out in order to ascertain biological factors associated with this trend change.

DESIGN AND METHODS

Retrospective analysis of CI patients was performed for the period 1996-2003. Changes in mean viral load and DR prevalence were assessed in CI patients (n = 2328) and compared to those in RI patients (n = 180) living in the same geographic area.

RESULTS

A decrease was observed in the prevalence of DR among RI patients, from 13.0% in 1997-2000 to 4.0% in 2001-2003 (P = 0.04). From 1996 to 2000, the mean viral load in the CI patients decreased by 1.34 log10, to remain steady thereafter. The proportion of CI patients who interrupt treatment increased steadily over 1997-2003 from 3.1% to 16.5% (P < 0.0001). Since 1999, when genotyping analysis became available, we have observed a 0.9 log10 decrease in mean viral load among 602 genotyped CI patients harbouring any major mutations.

CONCLUSION

The decrease in transmission of DR documented in Montreal since 2000 coincides with the drop in mean viral load observed in CI patients. Factors that contribute to the decrease in viral load include routine access to genotyping and availability of more potent antiretroviral drugs. Plasma viral load seems to represent the main predictor for the transmission of DR.

Epidemiologic Modeling to Evaluate Prevention of Mother???Infant HIV Transmission in Ontario

OBJECTIVES

To evaluate the impact of the Ontario HIV screening program to reduce mother-infant HIV transmission, this study estimated the proportion of preventable transmissions that were prevented.

METHODS

Using an iterative spreadsheet model, incidences of HIV infection, AIDS, and AIDS mortality in Ontario women were estimated by exposure category. The number of HIV-infected infants born to HIV-infected mothers was then estimated from conception and abortion rates of HIV-infected women of childbearing age and surveillance data. Finally, the proportion of HIV-infected mothers who received antiretroviral prophylaxis (ARP) was assessed.

RESULTS

HIV prevalence in 2001 among women of childbearing age was 1.05 per 1000. From 1984-2001, 764 infants were born to HIV-infected mothers and 180 were infected. From mid-1994-2001, 214 (39%) of the estimated 544 HIV-infected mothers were diagnosed; almost all received ARP. Of 118 preventable infections among infants born in this period, 39 (33%) were prevented. In 2001, only 46% of preventable infections were prevented and 11 preventable transmissions occurred.

CONCLUSIONS

HIV prevalence among women in Ontario increased >4-fold from 1990 to 2001. Fewer than half of HIV-infected mothers received ARP and preventable HIV infections continue to occur. Measures to further increase uptake of prenatal HIV screening must be instituted.

Delayed application of condoms is a risk factor for human immunodeficiency virus infection among homosexual and bisexual men

The objective of this analysis was to identify risk factors for recent human immunodeficiency virus (HIV) infection among homosexual and bisexual men in Ontario, Canada, during 1998-2001. Participants were recruited through the provincial HIV diagnostic laboratory and through physicians and community organizations. HIV test results were used to identify recent seroconverters (cases). A subsample of 183 men (62 cases and 121 controls) enrolled in the Polaris HIV Seroconversion Study as of June 2001 was analyzed. This analysis focused on sexual behaviors with partners who were HIV-positive or whose HIV status was unknown. In multiple logistic regression, independent risk factors were identified. Rates of unprotected receptive oral, insertive anal, and receptive anal sex and delayed application of condoms during receptive anal sex (RAS) were significantly higher among cases (97%, 41%, 53%, and 32%, respectively) than among controls (73%, 19%, 14%, and 2%). Independent risk factors for HIV infection were RAS without condoms (odds ratio = 4.4, p = 0.0004) and delayed application of condoms during RAS (odds ratio = 5.8, p = 0.01). There was an association with condom failure (breakage or slippage) during RAS that approached significance (odds ratio = 2.9, p = 0.09). Delayed application of condoms for RAS may result in contact with preejaculatory fluid. This behavior, which to date has received little attention, may pose as much risk for HIV infection as fully unprotected RAS.

The risks and benefits of accepting men who have had sex with men as blood donors

BACKGROUND

It has been suggested that men who have had sex with men (MSM) should become eligible to donate blood if they recently abstained from male-to-male sex.

STUDY DESIGN AND METHODS

The impact of a 12-month deferral policy for MSM on the risk of introducing contaminated units in the blood supply and the benefit of obtaining additional donations were estimated. Considered were the prevalence of HIV among MSM, the window period of infection, the rate of laboratory testing errors, and the occurrence of other system failures. This was compared with the risk and benefit that currently results from accepting female donors who have had sex with MSM.

RESULTS

The revised policy for MSM would potentially result in one HIV-contaminated unit for every 136,000 additional donations (95% CI, 1 in 69,000 to 1 in 268,000), for an overall increase in HIV risk estimated at 8 percent. The number of donations would increase by 1.3 percent (95% CI, 0.9%-1.7%). The risk-benefit ratio of currently accepting female partners of MSM is approximately five times lower.

CONCLUSION

The risk increment of accepting 12-month abstinent MSM would be very small but not zero. From a risk-benefit perspective, the current deferral policy for MSM is more efficient compared to an analogous hypothetical criterion for female partners of MSM.

Increases in HIV incidence among men who have sex with men undergoing repeat diagnostic HIV testing in Ontario, Canada

OBJECTIVE

To estimate HIV incidence density for different exposure categories among people undergoing repeat testing in Ontario, Canada.

METHODS

Persons using voluntary, diagnostic HIV testing at least twice were identified by computerized and manual record linkage. In the 1992-2000 period, 980 seroconverters and 340 994 repeat negative testers contributed 936 145 person years (PY) of observation. Incidence density (ID) was calculated according to Kitayaporn et al. Poisson regression was used to evaluate differences in incidence.

RESULTS

Among men who have sex with men (MSM), ID declined between 1992-1996, from 1.23 per 100 PY in 1992 to 0.79 per 100 PY in 1996 [relative risk (RR), 0.86 per year; 95% confidence interval (CI), 0.77-0.96]. Subsequently, ID increased to 1.39 per 100 PY in 1999 (RR, 1.18 per year; 95% CI, 1.05-1.34). In 2000, ID was 1.16 per 100 PY but this decrease was not statistically significantly different from 1999. MSM in their twenties had the highest ID in 1992-1996, but in 1996-2000 MSM in their thirties had the highest risk of infection. Among injecting drug users (IDU), ID decreased from 0.64 per 100 PY in 1992 to 0.14 per 100 PY in 2000 (RR, 0.87 per year; 95% CI, 0.80-0.94). Among heterosexuals, annual incidence remained constant at about 0.03 per 100 PY in 1992-2000.

CONCLUSIONS

Increases in ID were identified among MSM from 1996 to 1999. These findings are consistent with other research. Continued vigilance and improved surveillance are needed to better understand and control the epidemic.

No increase in HIV incidence observed in a cohort of men who have sex with other men in Montreal

To monitor HIV incidence we tested a cohort of men who have sex with men in Montreal for HIV every 6 months. Between 1996 and 2001, 17 out of 1244 participants seroconverted, for an HIV incidence of 0.56 per 100 person-years (py) (95% CL 0.29, 0.83). The incidence decreased over the study period, from 0.75 to 0.34 per 100 py; which was not statistically significant. An in-depth evaluation of the situation in Montreal could identify useful lessons for prevention efforts elsewhere.