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
Journal of Clinical Epidemiology
Centre for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, University of Cape Town, Anzio Road, Observatory, Cape Town, 7925, South Africa; Division of International and Environmental Health, Institute of Social and Preventive Medicine, University of Bern, Finkenhubelweg 11, CH-3012, Bern, Switzerland
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. © 2013 Elsevier Inc. All rights reserved.
antiretrovirus agent; acquired immune deficiency syndrome; adult; antiretroviral therapy; antiviral therapy; article; cohort analysis; female; follow up; human; Kaplan Meier method; loss to follow up; major clinical study; male; priority journal; Antiretroviral therapy; Cohort; Loss to follow-up; Program outcomes; Retention; Survival analysis; Acquired Immunodeficiency Syndrome; Adolescent; Adult; Africa, Southern; Anti-Retroviral Agents; CD4 Lymphocyte Count; Cohort Studies; Databases, Factual; Female; Humans; Lost to Follow-Up; Male; Middle Aged; Program Evaluation; Terminology as Topic; Treatment Outcome; Young Adult
5U01AI069924-06, NIH, National Institutes of Health