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Biomedical subjects

Keith Chan

Publications and source records attributed to Keith Chan.

7 recordsLinked to original sources
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↗
PubMed2002

Intensive care unit admission has minimal impact on long-term mortality.

OBJECTIVE: To measure the association between intensive care unit (ICU) admission and both hospital and long-term mortality, separate from the effect of hospital admission alone. DESIGN: Retrospective cohort study. SETTING: All hospitals in British Columbia, Canada, during 3 fiscal years, 1994 to 1996. PATIENTS: A total of 27,103 patients admitted to ICU and 41,308 (5% random sample) patients admitted to hospital but not to ICU. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Although ICU admission was an important factor associated with hospital mortality (odds ratio: 9.12; 95% confidence interval: 8.34-9.96), the association between ICU admission and mortality after discharge was relatively minimal (hazard ratio: 1.21; 95% confidence interval: 1.17-1.27) and was completely overshadowed by the effect of age, gender, and diagnosis. CONCLUSIONS: After controlling for the effect of hospital admission, admission to ICU has minimal independent effect on mortality after discharge.

Adult↗
PubMed2002

Prevalence and response to antiretroviral therapy of non-B subtypes of HIV in antiretroviral-naive individuals in British Columbia.

In North America, the B subtype of the major group (M) of HIV-1 predominates. Phylogenetic analysis of HIV reverse transcriptase and protease sequences isolated from 479 therapy-naive patients, first seeking treatment in British Columbia between June 1997 and August 1998, revealed a prevalence of 4.4% non-B virus. A range of different subtypes was identified, including one subtype A, 11 C, two D, five CRF01_AE, and one sample that could not be reliably subtyped. Baseline CD4 courts were significantly lower in individuals harbouring the non-B subtypes (P = 0.02), but baseline viral loads were similar (P = 0.80). In this study, individuals infected with non-B variants did not have a significantly different virological response to therapy after up to 18 months.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Azithromycin prophylaxis for Mycobacterium avium complex during the era of highly active antiretroviral therapy: evaluation of a provincial program.

Mycobacterium avium complex (MAC) disease was evaluated in a provincial program of azithromycin prophylaxis. Highly active antiretroviral therapy (HAART) was prescribed to 383 (65%) of 587 patients eligible for MAC prophylaxis (CD4 <75 cells/mm3). By use of an intent-to-treat analysis, MAC disease was observed in 21 of 271 patients who did not receive prophylaxis (incidence rate, 8 events per 100 person-years). MAC events occurred in 10 of 316 patients who received azithromycin (2.37 events per 100 person-years). Localized lymphadenitis compatible with immune reconstitution disease accounted for 23% of all MAC events, in contrast to studies in the pre-HAART era, where almost all cases were disseminated. None of the MAC isolates from the 10 prophylaxis failures were resistant to azithromycin. Azithromycin appeared to be protective against disseminated MAC in patients who were either unresponsive or nonadherent to HAART, but it did not prevent the development of immune reconstitution disease due to MAC.

AIDS-Related Opportunistic Infections↗
PubMed1994

Application of a Stable Isotope Technique for the Bioequivalency Study of Two Transdermal Nitroglycerin Systems.

A bioequivalency study of an experimental transdermal nitroglycerin system relative to the commercial Transderm-Nitro 0.4 mg/h system was performed on eight healthy volunteers by using an innovative stable isotope technique. Plasma clearance changes for nitroglycerin (NTG) during patch application were corrected with simultaneously administered intravenous infusion of (15)N-labeled nitroglycerin ((15)N-NTG) solution. The total amount of NTG transdermally absorbed (AUC x CL) during a 22-h application for the experimental system was not statistically different from that for the commercial system (9.7 plus minus 3.3 versus 8.1 plus minus 2.6 mg; p = 0.41). The analysis of residual drug content in the used system revealed that the difference in amounts of NTG delivered from the experimental and commercial systems were not significant (12.2 plus minus 3.1 versus 10.8 plus minus 3.1 mg; p = 0.29). With the isotope-labeled method, the absorption rate was evaluated at each time interval during the system application. The peak concentration values were 0.52 plus minus 0.21 mg h(minus sign1) at 1 h for the experimental system and 0.41 plus minus 0.15 mg h(minus sign1) at 2 h for commercial systems. After the peak concentrations, the absorption rates remained constant for both systems over the 16-h period. There was no statistical difference in absorption between the two systems at any sampling time. In this study, substantial fluctuations in the plasma concentrations of both NTG and (15)N-NTG were observed within and between subjects. In addition, the variability in plasma concentrations of NTG correlated well with that of (15)N-NTG for all participating subjects. The momentary changes of clearance, estimated from (15)N-NTG plasma data, were found to be responsible for the fluctuation of NTG in plasma.

Journal Article↗