Patterns of engagement in care during clients first 12 months after HIV treatment initiation in Zambia: a retrospective cohort analysis using routinely collected data

BackgroundThe first year after HIV treatment initiation or re-initiation is the period of highest risk of a treatment interruption or disengagement, yet little is known about the timing, patterns, and effects of interruptions in the early treatment period. MethodsUsing routinely collected electronic medical record data from 543 Zambian facilities from 01/01/2018 to 28/02/2023, we described patterns of engagement during the first year of HIV treatment. We categorized clinic visits and other interactions based on whether they were attended as planned ([≤]scheduled date), late [≤]28 days, or late >28 days). We used these visit categories to define engagement patterns for months 0-6 and months 7-12 after initiation or re-initiation as 1) continuous (attended all scheduled clinic and medication pickup visits as planned; 2) cyclical (attended [≥]1 visits late >28 days but returned to and remained in care); or 3) disengaged (missed a scheduled visit by >28 days and had no evidence of return). FindingsWe enrolled 159,429 adult participants (61% female, median age 33). Of the 513,322 interactions observed in the 12 months after initiation, 53% occurred as planned, 22% were late [≤]28 days late, 9% were >28 days late, and 17% were scheduled but never attended. In 0-6 months after initiation, 51% clients were continuously engaged, 12% cyclically engaged, and 33% disengaged. Two thirds of disengagers (21% of cohort) did not return after the initiation visit. During months 7-12, most clients who had been continuously engaged in months 0-6 (54%) remained continuous, while 18% moved to cyclical engagement. Among cyclical engagers in months 0-6, nearly half (47%) moved to being continuously engaged by month 12. Only 34% of the study population remained engaged continuously by the end of the 12-month period. InterpretationFewer than 60% of clients initiating ART care between 2018 and 2022 at Zambian facilities remained continuously engaged at month 6 and 34% at month 12. Cyclical engagement and frequent interruptions should be accepted as the norm and models of service delivery designed to accommodate them. FundingFunding for this study was provided by the Gates Foundation under INV-031690 to Boston University (SR principal investigator and award recipient). www.gatesfoundation.org. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Support for collection of the data used in this study was provided by the U.S. National Institutes of Healths National Institute of Allergy and Infectious Diseases (NIAID), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the National Cancer Institute (NCI), the National Institute on Drug Abuse (NIDA), the National Heart, Lung, and Blood Institute (NHLBI), the National Institute on Alcohol Abuse and Alcoholism (NIAAA), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the Fogarty International Center (FIC) under Award Number U01AI069924. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.