Date Published: September 5, 2011
Publisher: BioMed Central
Author(s): Siavash Jafari, Keith Chan, Kewan Aboulhosn, Benita Yip, Viviane D Lima, Robert S Hogg, Julio Montaner, David M Moore.
We examined trends in AIDS-defining illnesses (ADIs) among individuals receiving highly active antiretroviral therapy (HAART) in British Columbia (BC), Canada to determine whether declines in ADIs could be contributing to previously observed improvements in life-expectancy among HAART patients in BC since 1996.
HAART-naïve individuals aged ≥ 18 years who initiated treatment in BC each of the following time-periods 1996 – 1998; 1999 – 2001; 2002 – 2004; 2005 – 2007 were included. The proportion of participants with reported ADIs were examined for each time period and trends were analyzed using the Cochran-Armitage Trend Test. Cox proportional hazards models were used to examine factors associated with ADIs.
A total of 3721 individuals (81% male) initiated HAART during the study period. A total of 251 reports of ADIs were received from 214 unique patients. These occurred in a median of 4 months (IQR = 1-19 months) from HAART initiation. The proportion of individuals with a reported ADI did not change significantly from 4.6% in the earliest time period to 5.8% in the latest period (p = 0.181 for test of trend). There were no significant declines in any specific ADI over the study period. Multivariable Cox models found that individuals initiating HAART during 2002-04 were at an increased risk of ADIs (AHR = 1.55; 95% CI 1.04-2.32) in comparison to 1996 – 98, but there were no significant differences in other time periods.
Trends in reported ADIs among individuals receiving HAART since 1996 in BC do not appear to parallel improvements in life-expectancy over the same period.
The introduction of highly active antiretroviral therapy (HAART) in 1996 resulted in significant reductions in HIV/AIDS morbidity and improved survival among HIV-infected individuals compared to the pre-HAART era [1-6]. These improvements in survival were paralleled with reductions in the incidence of AIDS-related opportunistic infections, in the HAART-era compared to earlier time periods [7-9]. This trend is further illustrated by a continued reduction in the proportion of death due to ADI’s in HIV infected individuals [10,11].
The BC HIV, Drug Treatment Program (DTP) provides free antiretroviral medications to all medically eligible HIV-infected individuals free-of-charge . Data for this study were drawn from the HAART Observational Medical Evaluation and Research (HOMER) cohort. HOMER is a population-based cohort of antiretroviral-naïve HIV-infected adults 18 years of age and older who are enrolled in the DTP. The current HOMER dataset includes individuals who initiated HAART between August 1, 1996 and February 28, 2009, with follow-up until February 28, 2010. However, we restricted inclusion in this analysis to individuals who initiated HAART before December 31, 2007. Ethical approval for HOMER has been provided by the University of British Columbia Research Ethics Board.
A total of 3721 individuals (81% male) initiated HAART during the study period. The median baseline CD4 count was 190 cells/μL (interquartile range [IQR] 90 – 310 cells/μL) and 644 (15%) participants had AIDS at baseline. Table 1 represents the characteristics of participants in our drug treatment program by era of HAART initiation. There were significant differences in the median baseline CD4 cell count (p < 0.001), the gender distribution of participants (< 0.001) and the median age of study participants (p < 0.001) by time-period of HAART initiation but not in the proportion of individuals with a history of injection drug use (p = 0.842). The proportion of individuals with reported ADIs within 36 months of treatment initiation has not changed significantly among individuals accessing HAART in BC over a 12-year period. Considering that the baseline CD4 remained relatively constant, it was not surprising that the incidence of reported ADI's did not significantly change. However, this result is somewhat unexpected given the improvements in life-expectancy we have seen in the same period in this population . Additionally our observed bias toward decreased overall reporting in recent years from physicians in our program further supports our conclusion that ADI rates have not decreased over this period. Therefore, it appears that improvement in life expectancy of HIV/AIDS patients in this period is due to factors other than a decrease in the incidence of ADIs. Most likely this is due to reductions in non-AIDS related conditions, but may also be related to other factors, as well. The overall incidence of ADIs after HAART has not changed significantly after the introduction of the HAART in BC. These observations suggest that previously described recent improvements in the life expectancy among patients initiating HAART might have been because of reductions in the occurrence of other non-AIDS related clinical conditions. Further research is needed to examine this hypothesis. JSGM has received funding from Merck, Gilead and ViiV Healthcare to support research into Treatment as Prevention, consultancy fees from Merck, and speakers' fees from Clinical Care Options. RSH has received a research grant from Merck and a conference travel grant from GlaxoSmithKline. None of the other authors have any known competing interests. DMM, JSGM, RSH and SJ conceived of the study, and participated in its design and coordination. BY, VL and RSH supervised the data collection and the preparation of the dataset for analysis. KC conducted all of the data analysis. SJ wrote the first drafts of the paper, incorporated the comments of the other authors and was assisted by KA. All authors approved the final version of the manuscript for submission. Source: http://doi.org/10.1186/1742-6405-8-31