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Keith Chan

Publications and source records attributed to Keith Chan.

At least 19 recordsLinked to original sources
PubMed2006

Randomized clinical evaluation of self-screening for anal cancer precursors in men who have sex with men.

BACKGROUND: Self-collection of anorectal swab specimens could greatly facilitate the completion of prerequisite studies and future implementation of anal cancer screening among men who have sex with men (MSM). We therefore compared self- versus clinician- collection procedures with respect to specimen adequacy for cytological evaluation, concordance of paired cytological results, and concordance of cytological with biopsy results. METHODS: Paired self- and clinician- collected anorectal Dacron swabs for liquid-based (Thin Prep) cytological evaluation were collected in random sequence from a mostly HIV-1 seronegative cohort of young MSM in Vancouver. Slides were reviewed by one cytopathologist. Presence of any cytological abnormality (atypical squamous cells of uncertain significance, ASCUS, or above) prompted referral for high-resolution anoscopy and possible biopsy. RESULTS: Among 222 patient-clinician specimen pairs, most were adequate for cytological evaluation, though self-collected specimens were less likely to be so (83% versus 92%, McNemar's test p < 0.001). Cytological abnormalities, noted in 47 (21%) of self-collected and 47 (21%) of clinician-collected specimens (with fair agreement, kappa = 0.414) included, respectively: ASCUS (5%, 5%), and low-grade (13%, 13%) and high-grade (3%, 3%) squamous intraepithelial lesions. Among 12 men with biopsy-confirmed high-grade neoplasia, most had abnormal cytological results (including 6 patient and 9 clinician swabs) but few (2 patient and 1 clinician swab) were high-grade. CONCLUSION: Self-collection of anorectal swab specimens for cytologic screening in research and possibly clinical settings appears feasible, particularly if specimen adequacy can be further improved. The severity of biopsy-confirmed anorectal disease is seriously underestimated by cytological screening, regardless of collector.

Journal Article↗
PubMed2006

Disease progression in patients with virological suppression in response to HAART is associated with the degree of immunological response.

OBJECTIVE: To determine if immunological response is associated with disease progression in patients with virological suppression after initiating HAART. DESIGN: A cohort study of 1084 treatment-naive participants in the British Columbia HIV/AIDS Drug Treatment Program who had achieved viral loads < 500 copies/ml at 3-9 months after initiating triple-drug therapy. METHODS: Cox proportional hazards was used to model the association with disease progression of baseline variables, change in CD4 cell counts and CD4 cell count strata at 6 months. Logistic regression analysis was used to examine associations with two definitions of poor immunological response. RESULTS: Patients were followed for a median of 51.4 months. In univariate analyses, increases in CD4 cell counts of < 25 cells/microl and absolute CD4 cell counts of < 200 cells/microl were associated with an increased risk of death or new AIDS events. Two mulitivariate models, one including baseline CD4 cell count and change in CD4 cell count from baseline and the other including only absolute CD4 cell counts at 6 months, were found to predict disease progression in this setting. Increases in CD4 cell count of < 25 cells/microl were associated with increasing age and inversely associated with low baseline CD4 cell counts, high baseline viral loads and good adherence to therapy. CD4 cell counts of < 200 cells/microl at 6 months were associated with low baseline CD4 cell counts and having AIDS at baseline. CONCLUSION: Patients with virological suppression are still at risk for HIV disease progression if adequate immunological responses are not achieved.

Adult↗
PubMed2005

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.

AIDS Vaccines↗
PubMed2005

Back to work: correlates of employment among persons receiving highly active antiretroviral therapy.

The aim of this study was to quantify the level of employment at one-year and to determine potential predictors of future employment among HIV-positive persons on highly active antiretroviral therapy (HAART) in the province of British Columbia. Of the 392 individuals that were initially unemployed at baseline 63 (16.1%) found a job over the subsequent year. Factors associated with becoming employed included a baseline income over 10,000 dollars, having long-term disability or unemployment insurance as an income source, having higher CD4 cell counts, and better physical, social, and role functioning. Factors negatively associated with finding employment included having provincial assistance as an income source and having ever been an injection drug user (IDU). In multivariate analyses, not using provincial assistance as a source of income (Odds Ratio [OR] = 7.39; 95% CI: 3.26-16.7; p < 0.001) and higher MOS-SF role functioning (OR = 1.12 per 10 point increment; 95% CI: 1.03-1.21; p = 0.005) were independent predictors of becoming employed. In conclusion, our study demonstrates that while significant advances have been made in the reduction of HIV-related mortality, the majority of HIV-infected individuals on adequate treatment are still unable to be gainfully employed.

Adolescent↗
PubMed2005

Food insecurity and hunger are prevalent among HIV-positive individuals in British Columbia, Canada.

Hunger and food insecurity are important factors that may affect an individual's nutritional state and should therefore be assessed in nutrition surveillance activities. The objective of this study was to determine the level of food insecurity and hunger among HIV-positive persons accessing antiretroviral therapy in British Columbia. A cross-sectional study was performed in the BC HIV/AIDS drug treatment program, a province-wide source of free-of-charge antiretroviral medications. In 1998-1999, participants completed a questionnaire focusing on personal information, health, and clinical status. Food and hunger issues were evaluated with the Radimer/Cornell questionnaire. Overall, 1213 responding men and women were classified as food secure (52%), food insecure without hunger (27%), or food insecure with hunger (21%). In both categories of food insecurity, individuals were significantly more likely to be women, aboriginals, living with children, and to have less education, a history of recreational injection drug and/or alcohol abuse, and an unstable housing situation (P < 0.05). In logistic multivariate modeling, income < or = Can$10,000 [adjusted odds ratio (AOR) 3.78, 95% CI (2.53-5.65)], shared household with children [AOR 3.68, 95% CI (1.98-6.84)] and unemployment [AOR 3.15, 95% CI (1.94-5.13)] were the strongest predictors of hunger. In HIV-positive individuals, the occurrence of food insecurity was nearly 5 times higher than in the general Canadian population. The results should stimulate further research to identify to what extent hunger-associated factors are reversible with interventions built on nutritional and/or social strategies.

Adult↗
PubMed2005

Similar sexual behaviors with casual partners among gay men with and without a regular partner.

OBJECTIVES: We hypothesized that men in a relationship would engage in less risky sexual activity with their casual partners compared to men with only casual partners. STUDY: Cross-sectional data were collected between 1999 and 2003 in a study of young human immunodeficiency virus-seronegative gay men in Vancouver, British Columbia. We assessed the substance use and sexual behaviors of 156 men and compared those having casual partners in addition to 1 regular partner for the duration of the previous year (n = 43) to those reporting only casual partners during the previous year (n = 113). RESULTS: Men with just 1 regular partner were not significantly different from men without a regular partner with regard to sexual behaviors reportedly engaged in with casual partners, self-reported sexually transmitted infections diagnosed within the previous year, or demographic characteristics. Only previous use of poppers and higher frequencies of marijuana use were found among men without a regular partner. CONCLUSIONS: In our cohort, young gay men in a relationship do not appear less likely to engage in risky sex with casual partners than men with casual partners only.

Adult↗
PubMed2004

Impairments, activity limitations and participation restrictions: prevalence and associations among persons living with HIV/AIDS in British Columbia.

BACKGROUND: To measure the prevalence of and associations among impairments, activity limitations and participation restrictions in persons living with HIV in British Columbia to inform support and care programs, policy and research. METHODS: A cross-sectional population-based sample of persons living with HIV in British Columbia was obtained through an anonymous survey sent to members of the British Columbia Persons With AIDS Society. The survey addressed the experience of physical and mental impairments, and the experience and level of activity limitations and participation restrictions. Associations were measured in three ways: 1) impact of types of impairment on social restriction; 2) impact of specific limitations on social restriction; and 3) independent association of overall impairments and limitations on restriction levels. Logistic regression was used to measure associations with social restriction, while ordinal logistic regression was used to measure associations with a three-category measure of restriction level. RESULTS: The survey was returned by 762 (50.5%) of the BCPWA participants. Over ninety percent of the population experienced one or more impairments, with one-third reporting over ten. Prevalence of activity limitations and participation restrictions was 80.4% and 93.2%, respectively. The presence of social restrictions was most closely associated with mental function impairments (OR: 7.0 for impairment vs. no impairment; 95% CI: 4.7 - 10.4). All limitations were associated with social restriction. Among those with 5 vs. no limitation, 95%CI: 4.9-125.0). Among those with > 200 CD4 cells/mm3, the odds of higher restriction were increased with higher limitation (OR: 2.7 for limitation score of 1-5 vs. no limitation, 95%CI: 1.4-5.1; OR: 8.6 for limitation score > 5 vs. no limitation, 95%CI: 3.9-18.8), as well as by additional number of impairments (OR:1.2 for every additional impairment; 95% CI:1.1-1.3). CONCLUSIONS: This population-based sample of people living with HIV has been experiencing extremely high rates of impairments, activity limitations and participation restrictions. Furthermore, the complex inter-relationships identified amongst the levels reveal lessons for programming, policy and research in terms of the factors that contribute most to a higher quality of life.

Acquired Immunodeficiency Syndrome↗
PubMed2004

Sexual risk profile of young men in Vancouver, British Columbia, who have sex with men and inject drugs.

We compared sexual risk behaviors of men who have sex with men and inject drugs (MSM/IDU) with those of other men who have sex with men (MSM). Of 910 MSM surveyed, 106 (12%) injected drugs in the previous year. MSM/IDU were younger than MSM and more likely to be HIV-seropositive, Aboriginal, economically disadvantaged, engaged in the trade of sex for money or drugs, and to report having female sexual partners. MSM/IDU reported more casual sexual partners and in multivariate analyses were twice as likely to report unprotected receptive anal intercourse with casual partners. These results, combined with those from previous analyses, suggest that the higher risk for HIV seroconversion among MSM/IDU in this cohort is attributable mainly to sexual rather than injection-related exposures. Controlled assessments are needed to identify optimal sexual risk reduction strategies for MSM/IDU.

Adult↗
PubMed2004

Intensive care unit survivors have fewer hospital readmissions and readmission days than other hospitalized patients in British Columbia.

OBJECTIVE: Intensive care unit (ICU) patients who survive their hospital admission have a long-term survival that is similar to that of hospitalized patients who do not require ICU admission. The risk of future readmission to the hospital for these two patient groups is unknown. The objective of this study was to determine the association between ICU admission and number of readmissions to the hospital and number of readmission days. DESIGN: Cohort study for 3 yrs between 1994 and 1997. SETTING: All acute care hospitals in British Columbia, Canada. PATIENTS: A total of 23,859 patients admitted to the ICU and 40,052 patients admitted to the hospital but not the ICU (5% random sample of total). INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: We measured the number of readmissions to the hospital and the number of readmission days after discharge from the first admission to the hospital during the study period. For survivors to the end of the study period, patients who had been in the ICU had 0.66 readmissions per year and 5.29 readmission days per year compared with 0.73 readmissions per year and 5.48 readmission days per year for control subjects. After controlling for age, sex, socioeconomic status, number of previous ICU and hospital admissions, major clinical category during index admission, comorbidity score during index admission, length of hospital stay during index admission, size of index hospital, and period of follow-up, ICU admission was associated with fewer readmissions (survivors: rate ratio, 0.80; 95% confidence interval, 0.77-0.82; nonsurvivors: rate ratio, 0.85; 95%, confidence interval, 0.82-0.89) and readmission days (survivors: rate ratio, 0.91; 95% confidence interval, 0.87-0.95; nonsurvivors: rate ratio, 0.87; 95%, confidence interval, 0.81-0.92) than admission to the hospital but not the ICU. CONCLUSIONS: Survivors of a hospital stay that includes admission to an ICU have fewer hospital readmissions and readmission days after their discharge than do survivors of a hospital stay without intensive care.

Adolescent↗
PubMed2004

Initiating highly active antiretroviral therapy and continuity of HIV care: the impact of incarceration and prison release on adherence and HIV treatment outcomes.

OBJECTIVE: To examine the effect of incarceration within 12 months of initiating highly active antiretroviral therapy (HAART) on non-adherence and HIV-1 RNA suppression. METHODS: We compared the adherence and virological outcomes among participants in a population-based HIV/AIDS Drug Treatment Program in British Columbia, Canada, by history of incarceration in a provincial prison. Participants who were HIV-infected, naive to HAART and who were prescribed treatment between 1 July 1997 and 1 March 2002 were eligible for this study. Logistic regression was used to determine the factors associated with non-adherence and Cox proportional hazards modelling was used to determine the factors associated with HIV-1 RNA suppression adjusting for age, gender, history of drug use, baseline HIV-1 RNA, baseline CD4 cell count, type of antiretroviral regimen [two nucleosides + protease inhibitor (PI) vs two nucleosides + non-nucleoside reverse transcriptase inhibitor (NNRTI)], physician's HIV-related experience for each subject and adherence as measured by pharmacy refill compliance. RESULTS: There were 1746 subjects (101 incarcerated/1645 non-incarcerated) who started antiretroviral therapy between 1 July 1997 and 1 March 2002. Of those incarcerated, 50 initiated HAART while in prison and 27 subjects were released but returned to prison in the follow-up period. Subjects received antiretroviral therapy while incarcerated for a median number of 4 months [interquartile range (IQR): 2-10]. Multiple logistic regression results showed that a history of incarceration within 12 months of initiating HAART independently increased the odds of non-adherence [adjusted odds ratio (AOR): 2.40; 95% confidence interval (95% CI): 1.54-3.75]. A history of injected drug use was also associated with non-adherence (AOR: 1.49; 95% CI: 1.17-1.90). The following factors were negatively associated with non-adherence: older age (AOR: 0.81; 95% CI: 0.72-0.91), male sex (AOR: 0.50; 95% CI: 0.38-0.65) and higher physician HIV-related experience (AOR: 0.97; 95% CI: 0.96-0.98). In addition, a history of incarceration within 12 months of initiating HAART reduced the odds of achieving HIV-1 RNA suppression [adjusted hazards ratio (AHR): 0.68; 95% CI: 0.51-0.89]. Other factors negatively associated with viral suppression included a history of drug injection (AHR: 0.79; 95% CI: 0.69-0.91), two nucleosides + PI vs two nucleosides + NNRTI (AHR: 0.77; 95% CI: 0.69-0.87), higher baseline HIV-1 RNA (AHR: 0.66; 95% CI: 0.62-0.70). Higher adherence was positively associated with viral suppression (AHR: 1.38; 95% CI: 1.34-1.42). Among the 101 subjects who were incarcerated in the first year of starting HAART, the time spent in jail was positively associated with HIV-1 RNA suppression (HR: 1.06; 95% CI: 1.02-1.10). CONCLUSION: HIV-infected subjects with a history of incarceration within 12 months of initiating HAART have higher odds of non-adherence and, consequently, lower probability of achieving HIV-1 RNA suppression. The longer their sentence, however, the higher the probability of virological suppression. The British Columbian provincial prison system provided a structured setting for HAART but subjects are unable to continue this level of adherence upon release. Strategies to ensure continuation of HIV/AIDS care for HIV-infected individuals leaving the criminal justice system must be a public health priority.

Adult↗
PubMed2003

Length of ICU stay for chronic obstructive pulmonary disease varies among large community hospitals.

OBJECTIVE: To determine whether differences exist among large community hospitals in length of Intensive Care Unit (ICU) stay, hospital stay or hospital mortality for patients admitted to ICU and whose most responsible diagnosis was chronic obstructive pulmonary disease (COPD). DESIGN: Retrospective cohort study. SETTING: All seven large community hospitals in British Columbia, Canada. PATIENTS. All 296 patients who were admitted to ICUs and whose most responsible diagnosis was COPD during the 3 fiscal years 1994-1997. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After adjusting for age, gender, case-mix group, and co-morbidity, we found a significant difference in length of ICU stay for these patients among hospitals ( P <0.03). No differences were found in hospital mortality or length of hospital stay for the same patients among the same hospitals. CONCLUSIONS: There is significant variation in length of ICU stay for patients who are admitted to ICU and whose most responsible diagnosis is COPD, among large community hospitals. These small area variations may point to opportunities to improve efficiency of care. Further prospective, detailed data collection is required to validate these observations and to identify factors responsible for any differences found.

Aged↗
PubMed2003

Non-consensual sex experienced by men who have sex with men: prevalence and association with mental health.

Little is known about the psychosocial factors associated with sexual assault experienced by males. Men (N=358), 19-35 years of age, recruited by community outreach, completed questionnaires. Eligibility criteria included: being HIV-negative and self-identifying as gay or bisexual. Lifetime prevalence rates of childhood sexual abuse, juvenile prostitution, and adult sexual assault were determined. The mental health of this population was explored including associations between sexual victimization and mental health disorders (alcohol abuse, suicidal ideation and attempts, mood disorders, and poor self-esteem). Almost 1 in 10 of the men had engaged in juvenile prostitution, 14% were forced into sexual activity before 14 years of age, and 14% were sexually victimized after the age of 14. Those exposed to non-consensual sex were 2.9 (95% CI: 1.8-4.7) times more likely to abuse alcohol than those free of victimization. Those who reported childhood sexual abuse were 3.3 (95% CI: 1.7-6.4) times more likely to have attempted suicide. Juvenile prostitution was associated with current depression (OR=6.4; 95% CI: 2.8-14.9). Health professionals have the responsibility to respond competently and sensitively to victims of sexual violence. To do this, many need to recognize the prevalence of male sexual trauma, to deconstruct their personal beliefs about same-sex sexual violence, and to learn to ask sensitive questions in their assessment interviews.

Adult↗
PubMed2002

Willingness to participate and enroll in a phase 3 preventive HIV-1 vaccine trial.

OBJECTIVES: To assess the extent to which HIV-negative cohort study participants would be willing to participate (WTP) in future HIV vaccine trials, to explore enrollment into an ongoing phase 3 HIV vaccine trial, and to assess changing WTP in such trials over time. METHODS: The Vanguard Project is a prospective study of gay and bisexual men in the greater Vancouver region, British Columbia, Canada. Sociodemographic characteristics, sexual risk behavior, beliefs around HIV, and reasons for not participating in the AIDSVAX B/B trial were collected from self-administered questionnaires. Contingency table analysis compared subjects who were WTP with subjects who were not WTP. Logistic regression analyses identified possible predictors of WTP. A subset analysis was conducted to assess changes in WTP in 2001 versus 1997. RESULTS: Of 440 respondents, 214 (48.6%) were WTP, and 97 (22.0%) were not WTP. Those WTP were disadvantaged, sexually risky, and had a high-perceived HIV risk (all p <.05). Reasons for not participating in the AIDSVAX B/B trial included fear of health problems and having missed the deadline for enrollment (all p < 0.05). Multivariate analysis revealed that having had a regular sex partner (adjusted odds ratio, 0.48 [confidence interval, 0.25-0.92]) was a negative predictor whereas having a high-perceived HIV risk (adjusted odds ratio, 5.35 [confidence interval, 1.57-18.25]) was a positive predictor of WTP. Comparing WTP in 2001 with that in 1997, 24% of 100 participants who had been previously WTP were now not WTP. CONCLUSION: Improving community and participant knowledge about preventive HIV vaccine trials may help ensure informed consent. However, whether informing potential participants will reverse or contribute to the declining trend in WTP observed in this cohort warrants further investigation.

AIDS Vaccines↗
PubMed2002

Socioeconomic status, access to triple therapy, and survival from HIV-disease since 1996.

BACKGROUND: In the era before highly active antiretroviral therapy (HAART), socioeconomic status was associated with survival from HIV disease. We have explored socioeconomic status, access to triple therapy (HAART), and mortality in the context of a universal healthcare system. METHODS: We evaluated 1408 individuals who initiated double or triple therapy between 1 August 1996 and 31 December 1999, and were followed until 31 March 2000. Cumulative HIV-related mortality rates were estimated using Kaplan-Meier methods and Cox proportional hazards regression. RESULTS: In the overall Cox model, we found that adherence [risk ratio (RR) 0.83; per 10% increase], CD4 cell count (RR 1.53; per 100 cell decrease), and lower socioeconomic status (RR 2.19; high versus low), were associated with HIV-related mortality. However, socioeconomic status was not significant among patients prescribed triple therapy in a stratified analysis, or in a sub-analysis restricted to patients prescribed HAART in the initial regimen. When we investigated if inequitable access to HAART by socio-economic status could explain the discrepancy, we found that persons in the lower socio-economic strata were less likely to be prescribed triple therapy even after adjustment for clinical characteristics. CONCLUSION: In a universal healthcare system, socioeconomic status was strongly associated with HIV-related mortality. When we investigated possible explanations for this association, we found that individuals of lower socioeconomic status were less likely to receive triple therapy after adjustment for clinical characteristics. Our findings highlight the need for the monitoring of therapeutic guidelines to ensure equitable access, as treatment strategies are updated.

Adult↗
PubMed2002

Prescribing practices in a population-based HIV postexposure prophylaxis program.

OBJECTIVES: To characterize factors associated with being prescribed triple or double postexposure prophylaxis (PEP) against HIV in a population-based program. METHODS: Individuals potentially exposed to HIV received a 5 day starter kit of either double or triple antiretroviral PEP between April 1999 and November 2000 and did/did not receive the remaining 23 days PEP. Data were collected through dispensation of kits. Logistic regression identified characteristics independently associated with being prescribed triple therapy starter kits and with any 23 day follow-up. RESULTS: Of 2064 people receiving 5 day PEP [403 (20%) triple and 1661 (80%) double], 590 (29%) received 23 day follow-up. Independently associated with being prescribed triple therapy starter kits were being male [adjusted odds ratio (AOR) 1.38; 95% confidence interval (CI) 1.10-1.74; P = 0.006), occupational mucocutaneous injuries (AOR 1.70; 95% CI, 1.14-2.55; P = 0.010), and community needlesticks (AOR 2.04; 95% CI, 1.54-2.69; P < 0.001). Independently associated with being prescribed the 23 day follow-up were being male (AOR 1.24; 95% CI, 1.00-1.53; P = 0.04), community mucocutaneous incidents (AOR 2.83; 95% CI, 1.41-5.70; P = 0.004), community needlesticks (AOR 1.75; 95% CI, 1.33-2.29; P < 0.001), and having received triple therapy as the starter kit (AOR 2.61; 95% CI, 2.07-3.29; P < 0.001). CONCLUSIONS: Being prescribed triple therapy starter PEP was associated with being male and with experiencing an occupational mucocutaneous or community needlestick injury. Receiving the remaining 23 days PEP was associated with being male, experiencing a community mucocutaneous or needlestick injury, and triple therapy as the initial 5 day starter PEP.

Accidents↗