Background Appropriate use of highly active antiretroviral therapy (HAART) can markedly decrease the risk of progression to acquired immunodeficiency syndrome (AIDS) and of premature mortality. (rate 42 ADIs per 100 person-years). Since 1997 the number of ADIs decreased from 253 (rate 7 per 100 person-years) to 84 cases in 2013 (rate 1 per 100 person-years) (p-value equals to zero for the trend in the number of ADIs). We have also shown that out of 22 ADIs considered only PCP maintained its prominent ranking (albeit with much reduced overall prevalence). Finally we observed that over time very few deaths were related to AIDS-related causes especially in the most recent AM 1220 years. Interpretation We showed that the number of new ADIs and AIDS-related mortality have been decreasing AM 1220 rapidly over time in BC. These results provide further evidence that integrated comprehensive free programs that facilitate testing and deliver treatment and care to this population can be effective in markedly decreasing AIDS-related morbidity and mortality thus suggesting that controlling and eventually ending AIDS is possible. Funding The British Columbia Ministry of Health the US National Institutes of Health the US National Institute on Drug Abuse the Canadian Institutes of Health Research and the Michael Institute for Health Research. Introduction First introduced in 1996 highly active antiretroviral therapy (HAART) has had a dramatic impact on the natural history of human immunodeficiency virus (HIV)-related diseases including the acquired immunodeficiency syndrome (AIDS).1 Appropriate use of HAART can markedly decrease the risk of progression to AIDS and of premature mortality.2-4 Worldwide the expansion in the number of individuals accessing HAART since 2005 has been associated with a 30% decrease in AIDS-related mortality.5 More recently an association has been described between the expansion of HAART coverage and a decrease in the incidence of AIDS and AIDS-related mortality as well as a decrease in estimated HIV incidence.4 6 As a result there has been growing optimism regarding the possibility of ending the AIDS epidemic. 10-13 However this remains a matter CD63 of significant controversy.10-13 BC provides a unique environment to assess to what extent currently available tools can control the AIDS epidemic and whether the end of AIDS represents a realistic goal. BC’s HIV/AIDS epidemic is highly concentrated around urban centres. HIV/AIDS initially affected men who have sex with men (MSM) with a peak in 1994/1995. AM 1220 In 1996/1997 a rapid increase in cases among people who inject drugs (PWID) was seen.14 Currently the homeless individuals with mental health issues individuals of Aboriginal ancestry and women through sex work are overrepresented within the BC epidemic.14 In addition vertical transmission has been virtually eliminated in the province – only two infants were born to women who did not receive antenatal HAART prior to delivery in the last decade.14 HAART and related medical and laboratory monitoring have been fully subsidized in BC since 1996 and eligibility for HAART has been consistent with the IAS-USA guidelines.1 Since 2003 BC has had mandatory (nominal or non-nominal) HIV reporting legislation. Additionally the availability of unique personal health numbers for all BC residents provides a great opportunity to perform anonymized data linkages between administrative datasets to address our research question. Therefore in this paper we focused on assessing the population impact of the expansion of HAART coverage on changes in AIDS incidence and mortality since the beginning of the HIV epidemic in BC in 1981. Specifically we aimed to characterize the trends between 1981 and 2013 in AIDS-defining illnesses (ADIs) and in the number AIDS-related deaths. Methods Data Data for these analyses came from: (1) the BC-Centre for Excellence in HIV/AIDS (BC-CfE) which provided the list of eligible individuals for this study;15 (2) St. Paul’s Hospital which is the main HIV/AIDS care provider in BC where the BC-CfE is located and it provides real-time clinical data updates for AM 1220 all eligible individuals; (3) the BC Vital Statistics Agency which provides mortality data that are monthly linked with the BC-CfE database;15 and (4) the BC Cancer Agency which is the provincial agency responsible for providing all cancer-related care in BC which also provides data that are yearly linked to the BC-CfE database.15 ADI case-reports were obtained from the BC-CfE enriched with clinical records from St. Paul’s Hospital the BC.