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. Conclusion 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. Objectif Evaluer la variation de toutes les causes d'attrition (mortalité et perte de suivi (PS)) chez les personnes infectées par le VIH au Botswana, par district de santé, au cours du déploiement rapide et massif du Programme de Traitement National. Méthodes Analyse des données longitudinales recueillies systématiquement chez 226.030 patients qui ont reçu l’ART à travers le Programme de Traitement National du VIH/SIDA au Botswana dans tous les 24 districts de santé de 2002 à 2013. Une analyse temps‐événement a été utilisée pour mesurer les taux bruts de mortalité et de PS. Un modèle structural marginal a été utilisé pour évaluer les taux de mortalité et de PS par district au fil du temps, ajustés pour les facteurs de risque individuels (e