Variation in attrition at subnational level: review of the Botswana National HIV/AIDS Treatment (Masa) programme data (2002-2013).
OBJECTIVE
To evaluate the variation in all-cause attrition [mortality and loss to follow-up (LTFU)] among HIV-infected individuals in Botswana by health district during the rapid and massive scale-up of the National Treatment Program.


METHODS
Analysis of routinely collected longitudinal data from 226 030 patients who received ART through the Botswana National HIV/AIDS Treatment Program across all 24 health districts from 2002 to 2013. A time-to-event analysis was used to measure crude mortality and loss to follow-up rates (LTFU). A marginal structural model was used to evaluate mortality and LTFU rates by district over time, adjusted for individual-level risk factors (e.g. age, gender, baseline CD4, year of treatment initiation and antiretroviral regimen).


RESULTS
Mortality rates in the districts ranged from the lowest 1.0 (95% CI 0.9-1.1) in Selibe-Phikwe, to the highest 5.0 (95% CI 4.0-6.1), in Mabutsane. There was a wide range of overall LTFU across districts, including rates as low as 4.6 (95% CI 4.4-4.9) losses per 100 person-years in Ngamiland, and 5.9 (95% CI 5.6-6.2) losses per 100 person-years in South East district, to rates as high as 25.4 (95% CI 23.08-27.89) losses per 100 person-years in Mabutsane and 46.3 (95% CI 43.48-49.23) losses per 100 person-years in Okavango. Even when known risk factors for mortality and LTFU were adjusted for, district was a significant predictor of both mortality and LTFU rates.


CONCLUSIONS
We found statistically significant variation in attrition (mortality and LTFU) and data quality among districts. These findings suggest that district-level contextual factors affect retention in treatment. Further research needs to investigate factors that can potentially cause this variation.
Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Mansour
M
Farahani
Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Natalie
N
Price
Ministry of Health, Gaborone, Botswana.
Shenaaz
S
El-Halabi
Ministry of Health, Gaborone, Botswana.
Naledi
N
Mlaudzi
Ministry of Health, Gaborone, Botswana.
Koona
K
Keapoletswe
Ministry of Health, Gaborone, Botswana.
Refeletswe
R
Lebelonyane
Ministry of Health, Gaborone, Botswana.
Ernest Benny
EB
Fetogang
Ministry of Health, Gaborone, Botswana.
Tony
T
Chebani
University of Botswana, Gaborone, Botswana.
Poloko
P
Kebaabetswe
University of Botswana, Gaborone, Botswana.
Tiny
T
Masupe
University of Botswana, Gaborone, Botswana.
Keba
K
Gabaake
Centers for Disease Control and Prevention, Atlanta, GA, USA.
Andrew
A
Auld
University of Botswana, Gaborone, Botswana.
Oathokwa
O
Nkomazana
Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Richard
R
Marlink

ART
; 
HIV
; 
TAR
; 
VIH
; Botswana; abandono; antiretroviral therapy; attrition; marginal structural model; modelo estructural marginal; modèle structurel marginal; multilevel; multinivel; à plusieurs niveaux