Long term nationwide analysis of HIV and AIDS in Iceland, 1983-2012

Hlynur Indridason1, Magnus Gottfredsson 1,2, Sigurdur Gudmundsson 1,2, Bergthora Karlsdottir 2, Arthur Löve 1,3, Haraldur Briem 1,4
1Faculty of Medicine, School of Health Sciences, University of Iceland; 2Department of infectious diseases, 3Department of virology, Landspitali University Hospital of Iceland, 4Director of Health, Reykjavik, Iceland

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Background
Iceland is well suited for epidemiological research. This study provides a long-term epidemiological overview of the HIV epidemic in Iceland.

Methods
Retrospective study on all HIV positive individuals in Iceland, 1983-2012. Clinical data, CD4+ T-cell counts, plasma HIV RNA, proportion of late presenters and effectiveness of antiretroviral therapy (ART) were compared by study decades.

Results
In total, 313 were diagnosed with HIV in 1983-2012, thereof 222 (71%) men and 91 (29%) women. Most infections (65%) were acquired outside the country. Mean incidence of HIV was 3.7/100,000 inhabitants/year, with a significant increase in 2010-2012 (p = 0.0113), related to misuse of methylphenidate among intravenous drug users. Mortality decrased by 70% from the first half to the second half of the study period (p = 0.0275). Proportion of late presenters decreased from 74% in the first decade to 36% during the third (p = 0.0001). After 6 months of ART, CD4+ T-cells increased by 26 cells/µl on average in 1987-1995 (p = 0,174), by 107 cells/µl in 1996-2004 (p < 0,0001) and by 159 cells/µl in 2005-2012 (p < 0,0001). Similarly, progressively greater reductions in plasma HIV RNA were observed from 1996-2004 to 2005-2012 (p <0.0001).

Conclusions
HIV incidence remained relatively low in Iceland until 2010, when it increased significantly due to spread among IDUs. The majority of HIV infections diagnosed in Iceland were imported. With ever more effective drug treatments on CD4+ T-cells and plasma HIV RNA, the number of AIDS diagnoses and deaths has decreased dramatically.