Author(s): Solomon Odafe 1 , * , Kwasi Torpey 1 , Hadiza Khamofu 1 , Obinna Ogbanufe 1 , Edward A. Oladele 1 , Oluwatosin Kuti 1 , Oluwasanmi Adedokun 2 , Titilope Badru 2 , Emeka Okechukwu 3 , Otto Chabikuli 4 , 5
The last decade has seen a rapid scale up of ART programs in developing countries largely supported by the WHO's '3 by 5' initiative and the U.S President's Emergency Plan for AIDS Relief (PEPFAR). While the success of ART scale up has been widely acknowledged, retaining patients in care remains a well-documented challenge globally , . Retention is defined as the proportion of patients alive and receiving ART after a defined follow up period . Patients' retention is a function of attrition which includes deaths, patients lost to follow up and those who stopped treatment , . Most patient attrition occur within the first year on ART and patient retention across low and middle income countries in 2009 was estimated at 82% after 12 months on ART . Rosen et al in a meta-analysis in 2010 showed a retention rate of 86% at 6 months and 76% at the end of the year 2 . A combination of social, economic and structural factors contribute to attrition in ART programs in sub-Saharan Africa; they include formal and informal costs, poverty, and adverse effects of drugs, nondisclosure, long waiting times, alcohol abuse, and use of traditional medicines , , .
Nigeria, with about 2% of the world's population accounts for about 10% of PLHIV globally with an estimated at 3.3 million PLHIV . Of these, about a million need ART; the government with support of several partners has rapidly scaled up ART enrolment and has steadily increased number of patients initiated on ART from 90,008 in 2006  to an estimated 300,000 at the end of 2009 . Initiation of PLHIV on ART in the country is currently restricted to secondary and tertiary level hospitals. However to improve access to ART, the government plans to decentralize services to primary health centers . There are concerns that this will increase attrition because documented challenges of delivering ART in low resource settings such as shortages of health care staff, weak clinical care and diagnostic capacity and poor data management systems , ,  are more likely in lower levels of care.
A previous study in Nigeria, compared treatment outcomes in secondary and tertiary ART centers in adults' patients . This study compared the rates of attrition from care in tertiary and secondary health facilities in adults and children and examined effects of antiretroviral drugs (ARVs) and other clinical factors on attrition.
Materials and Methods
Study design and setting
This is a retrospective cohort study that reviewed patient level data collected between 2007 and 2010. The levels of care in the public sector in Nigeria are primary health centers, typically staffed by nurses, community health officers (CHOs), community health extension workers (CHEWs), junior CHEWs and environmental health officers; secondary...