The impact of the South African antiretroviral treatment programme on the age standardised incidence rate of Kaposi sarcoma, 1999 to 2016: an interrupted time series analysis.

Abstract Objective The objective of this study was to quantify the impact of the South African antiretroviral treatment programme on the age standardised incidence rate of Kaposi sarcoma among black South African residents of all ages. Methods We performed an interrupted time series analysis using routinely collected, histologically confirmed, surveillance data from the South African National Cancer Registry for the years 1999 to 2016. The analysis was performed using R statistical software. The total number of cases was 29 623 (12475 females and 17 166 males). The background antiretroviral treatment coverage was less than 1% at the time that the antiretroviral programme was introduced, rising to over 50% in 2016. Results In 1999, the age standardised rates were 1.48 and 2.82 cases per 100 000 per year for black females and males respectively. These rates increased to 5.52 and 7.46 in 2008 before declining. The antiretroviral treatment programme was started in 2004. Five years after 2008 (nine years after the antiretroviral programme was introduced), the predicted standardised rates were 58.3% and 50.3% lower, for females and males respectively, than what they would have been without the treatment programme. Conclusion Introduction of the antiretroviral treatment programme was associated with a decrease of over 50% in the predicted age standardised incidence rates of Kaposi sarcoma.