title: The need for second-line antiretroviral therapy in adults in sub-Saharan Africa up to 2030: a mathematical modelling study.
abstract: BACKGROUND
  The number of patients in need of second-line antiretroviral drugs is increasing in sub-Saharan Africa. We aimed to project the need of second-line antiretroviral therapy in adults in sub-Saharan Africa up to 2030.
  
  
  METHODS
  We developed a simulation model for HIV and applied it to each sub-Saharan African country. We used the WHO country intelligence database to estimate the number of adult patients receiving antiretroviral therapy from 2005 to 2014. We fitted the number of adult patients receiving antiretroviral therapy to observed estimates, and predicted first-line and second-line needs between 2015 and 2030. We present results for sub-Saharan Africa, and eight selected countries. We present 18 scenarios, combining the availability of viral load monitoring, speed of antiretroviral scale-up, and rates of retention and switching to second-line. HIV transmission was not included.
  
  
  RESULTS
  Depending on the scenario, 8·7-25·6 million people are expected to receive antiretroviral therapy in 2020, of whom 0·5-3·0 million will be receiving second-line antiretroviral therapy. The proportion of patients on treatment receiving second-line therapy was highest (15·6%) in the scenario with perfect retention and immediate switching, no further scale-up, and universal routine viral load monitoring. In 2030, the estimated range of patients receiving antiretroviral therapy will remain constant, but the number of patients receiving second-line antiretroviral therapy will increase to 0·8-4·6 million (6·6-19·6%). The need for second-line antiretroviral therapy was two to three times higher if routine viral load monitoring was implemented throughout the region, compared with a scenario of no further viral load monitoring scale-up. For each monitoring strategy, the future proportion of patients receiving second-line antiretroviral therapy differed only minimally between countries.
  
  
  CONCLUSIONS
  Donors and countries in sub-Saharan Africa should prepare for a substantial increase in the need for second-line drugs during the next few years as access to viral load monitoring improves. An urgent need exists to decrease the costs of second-line drugs.
  
  
  BACKGROUND
  World Health Organization, Swiss National Science Foundation, National Institutes of Health.
authors.affiliation: University of Bern, Institute of Social and Preventive Medicine, Bern, Switzerland. Electronic address: janne.estill@ispm.unibe.ch.
authors.forename: Janne
authors.initials: J
authors.lastname: Estill
authors.affiliation: World Health Organization, Department of HIV/AIDS, Geneva, Switzerland.
authors.forename: Nathan
authors.initials: N
authors.lastname: Ford
authors.affiliation: University of Bern, Institute of Social and Preventive Medicine, Bern, Switzerland.
authors.forename: Luisa
authors.initials: L
authors.lastname: Salazar-Vizcaya
authors.affiliation: University of Bern, Institute of Social and Preventive Medicine, Bern, Switzerland.
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Haas
authors.affiliation: University of Bern, Institute of Social and Preventive Medicine, Bern, Switzerland.
authors.forename: Nello
authors.initials: N
authors.lastname: Blaser
authors.affiliation: World Health Organization, Department of HIV/AIDS, Geneva, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Habiyambere
authors.affiliation: University of Bern, Institute of Social and Preventive Medicine, Bern, Switzerland.
authors.forename: Olivia
authors.initials: O
authors.lastname: Keiser
mesh_terms: D000328:Adult; D017954:Africa South of the Sahara; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008954:Models, Biological; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents