Comparison of methods for correction of mortality estimates for loss to follow-up after ART initiation: a case of the Infectious Diseases Institute, Uganda

• Published in: PloS one Vol. 8; no. 12; p. e83524
• Main Authors: Kiragga, Agnes N, Castelnuovo, Barbara, Musomba, Rachel, Levin, Jonathan, Kambugu, Andrew, Manabe, Yukari C, Yiannoutsos, Constantin T, Kiwanuka, Noah
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 31.12.2013; Public Library of Science (PLoS)
• Subjects: Acquired immune deficiency syndrome; Adult; AIDS; Analysis; Anti-HIV Agents - therapeutic use; Antiretroviral agents; Antiretroviral drugs; Antiretroviral therapy; Cohort Studies; Communicable diseases; Confidence Intervals; Drug therapy; Estimates; Female; Follow-Up Studies; Health aspects; Health sciences; Highly active antiretroviral therapy; HIV; HIV Infections - drug therapy; HIV Infections - mortality; Human immunodeficiency virus; Humans; Infectious diseases; Kaplan-Meier Estimate; Lost to Follow-Up; Male; Medical research; Medicine; Methods; Mortality; Nomograms; Patients; Public health; Sampling methods; Therapy; Uganda - epidemiology; Uganda; Kampala Uganda
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0083524

In sub-Saharan Africa, a large proportion of HIV positive patients on antiretroviral therapy (ART) are lost to follow-up, some of whom are dead. The objective of this study was to validate methods used to correct mortality estimates for loss-to-follow-up using a cohort with complete death ascertainment. Routinely collected data from HIV patients initiating first line antiretroviral therapy (ART) at the Infectious Diseases Institute (IDI) (Routine Cohort) was used. Three methods to estimate mortality after initiation were: 1) standard Kaplan-Meier estimation (uncorrected method) that uses passively observed data; 2) double-sampling methods by Frangakis and Rubin (F&R) where deaths obtained from patient tracing studies are given a higher weight than those passively ascertained; 3) Nomogram proposed by Egger et al. Corrected mortality estimates in the Routine Cohort, were compared with the estimates from the IDI research observational cohort (Research Cohort), which was used as the "gold-standard". We included 5,633 patients from the Routine Cohort and 559 from the Research Cohort. Uncorrected mortality estimates (95% confidence interval [1]) in the Routine Cohort at 1, 2 and 3 years were 5.5% (4.9%-6.3%), 6.6% (5.9%-7.5%) and 7.4% (6.5%-8.5%), respectively. The F&R corrected estimates at 1, 2 and 3 years were 11.2% (5.8%-21.2%), 15.8% (9.9%-24.8%) and 18.5% (12.3% -27.2%) respectively. The estimates obtained from the Research Cohort were 15.6% (12.8%-18.9%), 17.5% (14.6%-21.0%) and 19.0% (15.3%-21.9%) at 1, 2 and 3 years respectively. Using the nomogram method in the Routine Cohort, the corrected programme-level mortality estimate in year 1 was 11.9% (8.0%-15.7%). Mortality adjustments provided by the F&R and nomogram methods are adequate and should be employed to correct mortality for loss-to-follow-up in large HIV care centres in Sub-Saharan Africa.