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Home >> Publications >> Impact of definitions of loss to follow-up (LTFU) in antiretroviral therapy program evaluation: variation in the definition can have an appreciable impact on estimated proportions of LTFU.

Publication

Author(s):

Grimsrud AT, Cornell M, Egger M, Boulle A, Myer L.

Pub Title:

Impact of definitions of loss to follow-up (LTFU) in antiretroviral therapy program evaluation: variation in the definition can have an appreciable impact on estimated proportions of LTFU.

Pub Date:

Sep 30 2013

Pub Region(s):

Southern Africa

Journal Issue:

Epub

Page Number:
Epub

Journal:

Title: 
Journal of Clinical Epidemiology
Link: 
http://www.sciencedirect.com/science/article/pii/S0895435613001145

PubMed: 23774112
Pub PDF: PDF icon 23774112.pdf

Abstract:

OBJECTIVE: To examine the impact of different definitions of loss to follow-up (LTFU) on estimates of program outcomes in cohort studies of patients on antiretroviral therapy (ART).

STUDY DESIGN AND SETTING: We examined the impact of different definitions of LTFU using data from the International Epidemiological Databases to Evaluate AIDS-Southern Africa. The reference approach, Definition A, was compared with five alternative scenarios that differed in eligibility for analysis and the date assigned to the LTFU outcome. Kaplan-Meier estimates of LTFU were calculated up to 2 years after starting ART.

RESULTS: Estimated cumulative LTFU were 14% and 22% at 12 and 24 months, respectively, using the reference approach. Differences in the proportion LTFU were reported in the alternative scenarios with 12-month estimates of LTFU varying by up to 39% compared with Definition A. Differences were largest when the date assigned to the LTFU outcome was 6 months after the date of last contact and when the site-specific definition of LTFU was used.

CONCLUSION: Variation in the definitions of LTFU within cohort analyses can have an appreciable impact on estimated proportions of LTFU over 2 years of follow-up. Use of a standardized definition of LTFU is needed to accurately measure program effectiveness and comparability between programs.

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Citation:

Citation: Grimsrud AT, Cornell M, Egger M, Boulle A, Myer L. Impact of definitions of loss to follow-up (LTFU) in antiretroviral therapy program evaluation: variation in the definition can have an appreciable impact on estimated proportions of LTFU. J Clin Epidemiol. 2013 Sep;66(9):1006-13. doi: 10.1016/j.jclinepi.2013.03.013. Epub 2013 Jun 15. PubMed PMID: 23774112; PubMed Central PMCID: PMC3759810.